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Published by Ready Mixed Concrete Manufacturers' Association (RMCMA) 2008. Contact: B-5, Ground Floor, Neel Shantiniketan Co-op. Housing Society, Manipada Road, Opp. Mumbai University,Kalina, Santacruz (E), Mumbai 400 098, Tel.: 91-22-26654165, E-mail: [email protected] Web: rmcmaindia.org

Copyright © 2008 Ready Mixed Concrete Manufacturers' Association (RMCMA) B-5, Neel Shantiniketan CHS, Opp. Vidyanagari, Manipada Road, Kalina, Santacruz (E), Mumbai 400 098. All rights reserved. No part of this publication should be reproduced, copied and distributed in any form or by any means or stored in a data base or retrieval system without the prior written permission of RMCMA.

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CONTENTS

Sr. No. Description Foreword Preface The Quality Team Acknowledgement Message from NRMCA U.S.A Message from ERMCO BELGIUM Section I: Guidelines What is Quality? What are QA and QC? Complexities in providing Quality Concrete Company Information and Quality Policy Management Responsibility and Commitment QA-QC Plan Sources of Materials Monitoring Quality of Ingredients Cement Supplementary cementitious materials Chemical admixtures Water Aggregates Sampling and Testing of Concrete Process Control Upkeep of production facility Concrete mix design Control Charts Properties of Fresh Concrete Workability Density Temperature Properties of Hardened Concrete Strength Standard deviation Acceptance criteria Special QC techniques Internal quality audit report Cusum system Key Personnel Section II: Typical example 1 2 3 Introduction Tables and graphs Bureau of Indian Standards referred in Guidelines 45 46-61 62 Page No. 4 6 8 10 11 12 14 14 15 16 16 16 18 19 20 23 25 26 29 31 32 34 35 36 37 39 40 41 42 42 43

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FOREWORD

During the past decade, the construction industry in India witnessed remarkable growth, in which the ready-mixed concrete (RMC) industry can claim to be a proud partner. Historically speaking, India missed the benefits of RMC technology for decades. It was only in the early nineties that the industry was born, but growth really commenced from the second half of the nineties. During the past few years, housing and infrastructure have remained the major expansion areas. Faster speed and improved quality of concrete have been the two major demands of these sectors. Ready-mixed concrete was the right solution for this and it was heartening to see that the RMC industry responded positively to these demands. The result was the rapid growth of the RMC industry. This industry, which was initially confined to metropolitan cities, later spread to the two-tier and three-tier cities, vindicating the fact that RMC was a right solution for different markets. Currently, it is estimated that India produces around 2025 million m 3 of concrete annually from around 400-500 RMC facilities. The growth of the RMC industry brought in its wake certain challenges, chief amongst which was about the quality of concrete supplied by RMC plants. In this context, we are happy that the RMC industry came forward and has tried to evolve a self-regulatory framework for this. It is our pleasure to be associated with this exercise, spearheaded by the Ready-Mixed Concrete Manufacturers' Association (RMCMA). The exercise involved in-depth study of the regulatory practices in different countries, choosing the best international practices, aligning the regulatory framework with the provisions in the current codes of the Bureau of Indian Standards, evolving a system of audit of RMC facilities by external auditor, developing guidelines for the quality control and quality assurance of the final product, etc. We were happy to be actively involved during all these stages and could provide guidance to the RMCMA's Quality SubCommittee from time to time. The Quality Scheme of RMCMA is contained in two meticulously-prepared manuals, namely Quality Manuals Part I and II, which were finalized after thorough discussion and revisions. While Quality Manual Part-I incorporates an extensive Check List to be used for auditing RMC facility, procedures of audit, etc., Quality Manual Part-II contains guidelines for QA & QC of concrete, which are based on key provisions in different BIS codes. It is noteworthy that conformity with the Quality Manual-Part I through annual external audit of RMC facility is made mandatory for obtaining a RMCMA certification.

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It is heartening to note that the regulatory framework for quality is in place, the Quality Manual Part I and II have been finalized and that audits of nearly 50 RMC facilities located in different parts of the country have been successfully completed by external auditors till October 2008. Improvements in quality have to be a continuous process and hence the national Experts Committee would be reviewing the performance of the present Quality Scheme from time to time and would incorporate changes in its provisions, if necessary. We are of the opinion that a good beginning has already been made and everyone associated with construction needs to support this initiative from the RMC industry. We trust that these documents will become the cornerstone of high-quality concrete manufacturing. We are confident that alignment with these documents will ensure a healthy growth of the RMC industry in India.

For and on Behalf of the National Experts Committee Dr. A. Ramakrishna (Advisor, Larsen & Toubro Ltd.) Dr C. S. Viswanatha (Managing Director, Torsteel Research Foundation in India, Bangalore) Mr. Jose Kurian (Chief Engineer, DT & TDC, New Delhi) Dr A K Mullick (Former Director General, National Council for Cement and Building Materials (NCB), New Delhi) Mr. A. K. Jain (Technical Advisor, Grasim/ UltraTech Cement) Mr. P L Bongirwar (Former Dy. Managing Director, MSRDC, Mumbai) Mr. C M Dordi (Customer Support Group Head (West and Exports), Ambuja Cements)

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PREFACE

The first commercial ready-mixed concrete (RMC) facility in India was set up in Pune in 1992 and was followed by establishment of similar facilities in Mumbai, Bangalore, Chennai, Delhi, etc. The growth of the construction industry, particularly the rapid expansion of the housing and the infrastructure sectors, placed heavy demand on speed as well as quality in concrete construction. This gave an impetus to the growth of RMC industry, which took roots mainly in the urban and semi-urban areas of the country. Exact data on the growth of RMC industry is not available; however, it is estimated that India produced more than 25 million m3 of ready-mixed concrete in 2007-08 from around 400-500 RMC facilities and the number has been growing continuously. The spread of RMC facilities in urban India has brought in its wake certain challenges. Since RMC is not a finished product and the quality of the final product is dependent upon a host of factors some of which are beyond the control of the RMC producers there is likelihood of a variation in the uniformity and quality of the final product. Yet, the customer needs to be provided with some sort of quality assurance about the concrete supplied. This highlighted the need of developing a framework of quality for RMC. The Ready Mixed Concrete Manufacturers' Association (RMCMA), India, which was established in March 2002 and has been striving hard to bring the Indian RMC industry at par with the industries in advanced countries, has taken up this challenge. After an in-depth study of the prevailing quality systems in different parts of world, mainly from the U.S.A.,U.K., Canada, the RMCMA decided to develop a selfregulatory framework for Quality of RMC. It formed a Sub-Committee on Quality, consisting of experienced quality personnel from member companies. Further, a committee of National Experts was also set up. The Quality Sub-Committee, which worked under the guidance of the National Experts Committee and the Managing Committee of RMCMA, put in Herculean efforts to evolve Quality Scheme for RMC in India. The Quality Scheme has been developed in two parts and the details are contained in two manuals, namely, "Quality Manual Part I and Part II". Both manuals have been developed after extensive deliberations in the Quality Sub-Committee and also in the joint meetings of the entire Quality Team. The drafts of the Quality Manuals Part I and II were modified on several occasions. The first part of the scheme essentially consists of an annual audit of RMC facility by an external auditor. The audit is based on an extensive Check List included in Quality Manual Part I. While developing the Check List, it was ensured that the provisions in the same meet most of the stipulations in the Indian Standard on Ready Mixed Concrete, IS 49263 (second revision) and the other relevant codes on concrete such as IS 4561, IS 91032 and many others. In fact, the requirements of the Check List, in some cases, exceed those of the codes. Thus, RMCMA certification through the external audit would provide assurance to the users that the production facilities of the certified plant conform to the requirements of the IS code. Before the Check List was finalized, mock audits of number of RMC facilities were conducted by selected members of the Quality Sub-Committee and the Check List provisions were modified after gaining practical experience. Incidentally, the Quality Manual Part I also includes the detailed procedure of audit, detailed procedure of audit, selection criteria of auditors, sample certificate, selection criteria of auditors, sample certificate, etc. It may be Emphasized that successful completion of

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external annual audit is mandatory for obtaining RMCMA certification However, it needs to be pointed out that availability of proper plant and equipment is only one of the factors -- although a very vital one -- that controls quality of concrete. No claim is therefore made that certification of RMCMA will necessarily assure delivery of high quality concrete. The RMCMA certificate should therefore be accepted precisely for what it is -- evidence that a certified production facility do possess capabilities to produce quality concrete. The existence of these capabilities is likely to reduce the incidence of deficiencies in the quality of final product. The Quality Team seriously deliberated on the issue of product certification too. It was felt that quality of the product involves contractual issues between the RMC producer and his/her clients. Further, different member companies follow different quality practices and are in competition with each other on quality parameters. The Quality Team therefore felt that product quality cannot be brought under certification at the current stage; instead, it was decided that the RMCMA should develop a Guideline document on QA and QC of Concrete for its member companies. The Quality Sub-Committee prepared the draft guidelines which were deliberated in various meetings and several improvements were made based on the guidance provided by the National Experts. It is recommended that each RMC facility should prepare its own QC Manual II following the minimum benchmarks suggested in the guideline document. Such document, which incidentally needs constant updating, would demonstrate RMC producer's commitment to quality concrete. The external audits of RMC facilities of member companies commenced in March 2008 and we are pleased to inform that till October 2008, more than 50 RMC facilities from different parts of the country are successful in obtaining certification. The list of these facilities as well as the names of the auditors who audited these facilities is available at www.rmcmaindia.org. The Quality Team of RMCMA will continuously review the progress in the implementation of the Quality Scheme. It would be open to constructive suggestions and based on the feedback from field, would modify the provisions in the Quality Manual Part I and II, if found necessary. The RMCMA has developed close ties with the National Ready Mixed Concrete Association (NRMCA), U.S.A and the European Ready Mixed Concrete Organization (ERMCO). We are happy to inform that these leading world organizations are supportive of the efforts being made by the RMCMA in developing the quality scheme. We are pleased to enclose the messages of appreciation from these organizations. The Quality Team of RMCMA strongly believes that the self-regulatory quality framework initiated by the RMCMA would go a long way in improving the quality of concrete produced by RMC plants and providing assurance to customers.

For and on Behalf of Quality Sub-Committee (Vijay R. Kulkarni) Convener, Quality Sub-Committee, RMCMA

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THE QUALITY TEAM

National Experts Committee

· · · · · · · Dr. A. Ramakrishna- Advisor, Larsen & Toubro Ltd. Dr C. S. Viswanatha, Managing Director, Torsteel Research Foundation in India, Bangalore Mr. Jose Kurian- Chief Engineer, DT & TDC, New Delhi Dr A K Mullick, Former Director General, National Council for Cement and Building Materials (NCB), New Delhi Mr. A. K. Jain- Technical Advisor, Grasim/ UltraTech Cement Mr. P L Bongirwar- Former Dy. Managing Director, MSRDC, Mumbai Mr. C M Dordi- Customer Support Group Head (West and Exports), Ambuja Cements

RMCMA's Sub-Committee on Quality

· · · · · · · · · · · · Vijay R. Kulkarni, Convener, Quality Sub-Committee, RMCMA Mr. Rajiv Talwar, Head QA, ACC Concrete Ltd. Dr. P. Dinakar, ACC Concrete Ltd (From inception till December 2007) Mr. Harpal Singh Sehmi, ACC Concrete Ltd (From inception till June 2007) Mr. Anuj Maheshwari- Head, Technical, Grasim Industries Ltd. Mr. S. G. Bhat, Manager QC, Lafarge Aggregate & Concrete Pvt. Ltd. Mr. Hiren Joshi., QA-QC In-charge, Lafarge Aggregate & Concrete Pvt. Ltd. Mr. S. D. Govilkar, Deputy General Manager(Technical), RMC Readymix (I) Pvt. Ltd. Mr. Girish Bonde, Head, Technical, RDC Concrete India Pvt. Ltd. Mr. Bilal Baig, Manager, Quality, Godrej & Boyce Mfg. Co. Ltd. Mr. Awadhoot Sawant- Dy. Manager RMC, Godrej & Boyce Mfg. Co. Ltd. (From inception till Nov. 2007) Mr. D. Mohan, Manager Technical, IJM Concrete Products Pvt. Ltd.

RMCMA's Managing Committee

· · · · · · · · Mr. Ganesh Kaskar, President, RMCMA & Ex. Dir. and CEO, RMC Readymix (I) Pvt. Ltd. Mr. Hans Fuchs, Vice-President, RMCMA and Managing Director, ACC Concrete Ltd. Mr. Racy Sidhu, Vice-President, RMCMA and BU Manager-RMC, Lafarge Aggregate & Concrete Pvt. Ltd. Mr Vivek Agrawal, .Ex. President, Grasim Industries Ltd. Mr. B K Shrikhande, Former Vice-President, ACC Concrete Ltd. ( from inception till October 2007) Mr. Sanjay Bahadur, Former Managing Director, ACC Concrete Ltd. (from Nov. 2007 to June 2008) Mr.Akash Gonge, Secretary, RMCMA, and General Manager (RMC), Godrej & Boyce Mfg. Co. Ltd. Mr S.R. Kumar, Immediate Past President, RMCMA ( from inception to August 2008)

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· · · · · ·

Mr Uday Shankar, Ex. Director, RDC Concrete India Pvt. Ltd. Mr. R Krishnachander, Vice-President-Business Development, India Cements Ltd. Mr. Balaji Moorthy, President-Marketing, Madras Cement Ltd. Mr. Prakash Menon, General Manager, IJM Concrete Products Pvt. Ltd. Mr. M A Mathew, Proprietor, MC Duramix Mr. Vijay R. Kulkarni, Principal Consultant, RMCMA

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ACKNOWLEDGMENT

We are grateful to each member of the RMCMA's Sub-Committee on Quality for carefully scrutinizing different provisions in Quality Manual Part I and II. The provisions were thoroughly discussed in the meetings of the Sub-Committee and several modifications were made after reaching broad consensus. The help rendered by Sub-Committee members is highly appreciated and we are thankful to them for their involvement and efforts. We are also indebted to all members of the National Experts Committee and the Managing Committee of RMCMA who have provided broad guidance on different aspects of the provisions in both manuals. They not only carefully scrutinized the provisions in the Manuals but also helped the RMCMA in finalizing its approach to the Quality Scheme by offering valuable suggestions. The RMCMA would like to record its deep sense of gratitude towards the members of the Experts Committee for their valuable guidance. The Quality Team would also like to thank the National Ready Mixed Concrete Association (NRMCA), U.S.A., particularly, Mr. Robert Garbini, President and Dr Colin Lobo, Senior Vice-President (Engineering), for the help rendered in providing guidance on the quality practices followed by NRMCA. We are also thankful to the European Ready Mixed Concrete Organization (ERMCO) for the support rendered to us.

For and on Behalf of Quality Sub-Committee

(Vijay R. Kulkarni) Convener, Quality Sub-Committee, RMCMA

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Section I: Guidelines

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1. What is Quality?

1.1 The term quality has been defined differently by different experts. For example, Deming defines it "Meeting the customers' needs"; Juran says it is "Fitness for use", whereas Crosby defines it as "Conformance to requirements". One more definition of quality can be "Satisfaction of stated and implied needs". Quality can have separate meaning. It can have subjective meaning, when it is used to indicate elegance or luxury. Quality can be relative, when the term is used to indicate grade (e.g. 5-star hotel). It can have objective meaning when it is used to indicate a specific requirement or fitness for purpose (e.g. M30/M40 grade of concrete). 1.2 The term quality has a much wider and an all-encompassing significance when applied to any multidimensional activities. In the context of construction industry, quality is the slated and implied needs of the users/owners -- who should be assured of the required serviceability and safety, without undue maintenance -- but also the slated and implied needs of the client/promoters who should be assured of adequate returns on their investments. Quality in construction can be said to have been achieved if it is completed without time and cost overruns, ensuring the required serviceability, durability and safety, without undue maintenance.

2. What are QA and QC?

2.1 In the literature on quality, one would often notice the use of two terms, namely, quality control (QC) and quality assurance (QA). In day-to-day practice, there is a tendency to use these terms imprecisely. It would therefore be appropriate to have clarity about the exact meaning of these terms.. 2.2 Quality control (QC), sometimes called process control, is defined as "the operational techniques and activities that are used to fulfill requirements of quality". It is the sum total of activities performed by the seller (producer) to make sure that a product meets contract specifications and requirements. QC is often confused with control testing. The basic quality control concept, as promulgated by Prof. Juran, is to "control the mass and not the piece". The main problem about quality control is that it is an "after event" operation, designed to prevent defective items from passing through the system. What happens when a product fails? The consumer's risk is that a bad batch may get accepted, while the producer's risk is that a good batch may be rejected. This gave rise to the concept of quality assurance (QA). 2.4 Quality assurance (QA) can be defined as all those planned activities and systematic actions necessary to provide adequate confidence that a product or service will satisfy the given contractspecific requirements. Quality assurance provides consistency and an assurance (in the form of certified records) that the established QC procedures have been carried out in full. Thus, quality control is part of quality assurance. Within an organization, quality assurance serves as a management tool; in contractual situations, quality assurance serves to provide confidence in the supplier.

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3. Complexities in providing Quality Concrete

3.1 As regards ready-mixed concrete (RMC), the problem of providing QA and QC becomes more complex. This is because RMC is an unfinished product at the time of delivery. In its "as sold" condition, the product is perishable and will not remain in plastic and unhardened condition beyond a limited time. Construction materials like steel, aluminum, glass, etc are factory-produced finished products and the producers are in a position to control its final quality before delivery. This is not the case with ready-mixed concrete. The quality of finished concrete is affected by a host of factors such as: · · · · · · variability in the quality of the different ingredients such as cement, aggregates, sand, water and mineral and chemical admixtures, selection of ingredients which depends up on the end use and client's requirements, proportions of ingredients, a variety of process parameters, affecting homogeneity of mixing and other properties, conditions involving transportation, placement, finishing, curing and protection of concrete, variation in external environmental conditions such as changes in temperature, humidity and wind speed, which can adversely affect the properties of concrete.

3.2 The main quality parameters of concrete are its workability, homogeneity and compactibility at pour site, 28-day compressive strength and long-term durability. Amongst these parameters, durability is indirectly controlled by adopting certain code-specified limiting norms, e.g. minimum cementitious content, maximum free water-binder ratio, minimum grade of concrete, etc (for example, Tables 3 and 5 of IS 456 2). The workability at pour site, which is usually measured in terms of slump, is affected by numerous factors and the RMC producer has to take proper precautions to maintain the desired values of slump at pour site, making use of his expertise and experience, especially when the weather conditions are harsh and there could be bottlenecks in transportation, involving long delays. The specified compressive strength of concrete cannot be verified at the time of sale, as an overwhelming majority of the contracts are based on the 28-day strengths. 3.3 Thus, providing quality concrete on a consistent basis is indeed a complex job. With a view to tide over this complexity, RMC producer needs to be committed to well-organized quality control and quality assurance systems. This Guideline document along with the interrelated document (QC Manual Part-I) provide necessary tools which can be used by RMC producers to produce quality concrete on a consistent basis. It may be mentioned here that QC Manual Part-I contains a comprehensive Check List, based on which audit of the production facility by external auditor should be organized each year through the good offices of RMCMA. Such audit, which provides assurance to the customers that the tools available with the RMC producer are capable of producing quality concrete, is mandatory to obtain certification from RMCMA. Since product quality is governed by contractual agreement between the producer and the client and each company follows different system of controlling quality of its own products, it was felt that audit based on the Guidelines suggested in the Part-II of this Manual would not be possible and hence not proposed. Yet, it is strongly recommended that each RMC facility should prepare its own QC Manual following the minimum benchmarks suggested in this document. Such document would demonstrate RMC producer's commitment to quality concrete.

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3.5 This Guideline document recommends a broad framework of QA and QC which is strongly recommended for adoption by RMC producers. It is believed that adoption of the guidelines would help RMC producers in establishing his own system that would provide assurance of his capabilities in producing quality concrete on a consistent basis.

4. Company Information and Quality Policy

4.1 The Guideline provides an opportunity for each Company to describe its background, organizational structure, its products and services, mission statement, quality policy, etc. Thus, when preparing its own QC Manual, it I suggested that the following information may be incorporated in the same: · brief history of the Company · growth trends of the Company including some its recent initiatives · geographical locations of its production facilities · description of products and services · any additional information that the Company may perceive to be beneficial 4.2 Many companies have well-defined "Mission" and "Vision", embodied in Company statements. It would be most appropriate to include such statements in the QC Manual. Further, many companies have a clear-cut "Quality Policy". In case such policy has already been evolved, the same should be included in the QC Manual. In fact, incorporation such policy in the QC Manual would be welcomed by customers.

5. Management Responsibility and Commitment

5.1 The production of concrete having consistent quality demands involvement and commitment from all those connected with the production process, either directly or indirectly. Quality is not merely the concern of the QC department; it is the concern of everyone involved in the process -- the marketing personnel who book orders and keep in touch with customers, the procurement personnel who procure different ingredients of concrete as well as equipment, production personnel involved in producing concrete as per the recipe agreed upon, and the QC team involved in testing, mix proportioning, monitoring and analyzing test results. Implementation of quality system often leads to reduction in the rate of failures, which can translate in to reduction in cost for the producer. However, for this to happen, everyone needs to be committed to quality. In particular, what is important is the commitment and willingness of the top management of the Company to maintain product quality regardless of the competitive pressures. The responsibilities of management personnel as well as their authorities should be clearly spelt out.

6. QA-QC Plan

6.1 This document suggests that each RMC production facility should establish its own QA-QC Plan, for which these guidelines can serve as a basis. It is emphasized that the guidelines can be treated as minimum benchmarks. Different RMC production facilities certainly have the freedom to excel beyond the minimum benchmarks. In fact, if the publication of these benchmark guidelines results in the emergence of a true competitive spirit amongst different RMC production facilities, and they start competing with each other by excelling the given benchmarks, customers would be the final beneficiary.

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6.2 It is suggested that the QC Plan should have the following elements: o Management of the quality of ingredients: o Sources/location of different materials o Crucial tests and testing frequencies for different ingredients for monitoring their quality o Process Control o Inspection and checking of different components of plant and other equipment and their frequency o Concrete mix design: Data on laboratory and plant trials o Sampling of concrete o Properties of fresh concrete o Data on slump, temperature, density, o Properties of hardened concrete o Data on compressive strengths of concrete at various ages; flexural strength (whenever specified) o Acceptance criteria o Standard deviation o Special QC techniques o Internal quality audit o Special techniques o Key personnel: o Data pertaining qualification, experience, and training of all personnel involved in production, quality control, marketing, etc.

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7. Sources of Materials

7.1 RMC supplier would prefer to have the same source for the materials used in day-to-day production. This is because a change in the source of the material may affect its properties and hence would warrant re-proportioning/redesigning of mixes, which is a time-consuming process. Therefore, RMC supplier would always try to avoid frequent changes in the sources of materials. However, a variety of factors such as shortage in the supply of materials, environmental restrictions on dredging and mining, transportation bottlenecks, abnormal increase in the cost of material from a particular source, etc. compel the RMC producer to make changes in the sources of input materials. Considering this, it would be advisable to document the sources of all ingredients used in production. In case of any quality problems, such documentation would be quite useful in tracking faulty materials sources, if any. Table 1 suggests the format for such documentation.

Table 1: Sources of different materials, and their period of use

Material Type/ Class OPC Cement PPC PSC Other Fly ash Slag Silica fume Water Ice Fine aggregate Coarse aggregate Quarry fines W.R. Agent H.R.W.R.A. Retarder Others River sand Manufactured sand 40-mm down 25-mm down 12.5-mm down Siliceous Calcareous 43 grade 53 grade Source Name of Supplier/ Factory/ brand Location

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8

Monitoring Quality of Ingredients

8.1 Cement 8.1.1 RMC producers in India commonly use three types of cements, namely, · ·

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Ordinary Portland cement (OPC) o 43 grade conforming to IS 81123 o 53 grade conforming to IS 122694 Portland Pozzolana Cement (PPC) conforming to IS 14895 Portland Slag Cement (PSC) conforming to IS 4556.

8.1.2 Although cement is a factory-produced material, there may be variation in the properties between

two consignments, even from the same factory. RMC producers usually prefer to have a long-term understanding with a particular cement producer. However, at times, they are constrained to use different brands from different manufacturers. Since the properties of the cement have close bearing on the properties of concrete, it would be appropriate to document the key physical properties of cement. Fortunately, most of the cement manufacturers do provide a test certificate on the properties on a regular basis, enabling documentation of such properties. Some RMC producers have facility for testing certain key physical properties of cement in their central laboratory. If such a facility is in use or in case RMC producers get the cement samples tested from a third-party laboratory, the results should be appropriately documented. Table 2 provides a format for such documentation. The table also includes the minimum and maximum provisions from the relevant Indian codes for the sake of immediate comparison.

Table 2: Selected physical properties of cement

Property Date of testing Type of cement Manufacturer I PPC Test Provisions of results* IS 14895 300 (min) 3-day 7-day 28-day Setting time, minute Initial Final Soundness, mm Loss on ignition, % % of mineral admixture (fly ash or slag) in PPC or PSC 15-35 % fly ash 30 (min) 600 (max) 10 (max) 30 (min) 600 (max) 10 (max) 4 (max) 35-70 % slag 30 (min) 600 (max) 10 (max) 16 22 33 Manufacturer II OPC 53 grade Provisions Test of IS results* 122694 225 (min) 27 37 53 Manufacturer III PSC Test Provisions of results* IS 4556 225 (min) 16 22 33

Fineness, m2/kg Min. compressive strength, MPa

* Based on data from manufacturer's certificate or in-house testing or testing done in a third-party lab.

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8.2 8.21

Supplementary Cementitious Materials RMC producers generally use the following three types of supplementary cementitious materials (SCMs): · · · Fly ash, Ground granulated blast furnace slag (GGBS), Condensed silica fume.

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It is well known that SCMs, possessing either pozzolanic or latent hydraulic properties, improve a host of properties of concrete, both in its fresh and hardened states. In particular, the use of these materials improves the workability and helps concrete in achieving higher long-term strength gain and improved durability leading to enhanced sustainability. However, these benefits would be achieved only when it is ensured that the SCMs possess the requisite properties; otherwise, they may just act as inert fillers. For RMC producer, the best way to ensure this is to verify as to whether the physical and chemical properties of the SCM used conform to the code-specified requirements. While fly ash and condensed silica fume should respectively conform to IS 3812 153888, GGBS should conform to IS 12089 : 19879 and BS 6699. (Part 1)7 and IS

8.2.1

Fly ash

8.2.1.1Fly ash or pulverized fuel ash (PFA) is a by-product from thermal power plants. Depending on the type of coal used for burning, fly ash could either be of silicious variety (produced from bitimunous coal and having CaO < 10%) or calcareous variety (produced from lignite coal and having CaO > 10%). While finely-divided silicious fly ash has pozzolanic nature, the calcareous fly ash has both pozzolanic and hydraulic properties. However, not all fly ashes available from thermal power plants can be suitable for use in concrete. If fly ash is obtained from the same source, there will not be much variation in the chemical properties of fly ash; however the physical properties may vary depending upon the collection and separation and grinding system used. The IS 38127 has stipulated certain minimum physical and chemical requirements. RMC producer needs to ensure that the fly ash received by him has supplementary cementitious properties. It would therefore be appropriate if the fly ash supplier furnishes a test certificate along with each consignment. 8.2.1.2Before the source of the fly ash is fixed, it is essential that all the physical and chemical requirements as given in IS 38127 are complied with. Once the source is fixed, only the physical requirements of fly ash need to be monitored. Amongst the various physical requirements mentioned in Table 3, the requirement of particles retained on 45 µ sieve can be assessed quickly by wet sieving test. It would therefore be a good practice to carry out this test in the in-house laboratory before each consignment is accepted. It is suggested that the remaining four physical requirements, namely Blaine's fineness, lime reactivity, 28-day compressive strength and soundness, should be checked once in 3 months or with the change in source. 8.2.1.3With a view to control the consignment-to-consignment variation in the quality of fly ash, IS 38127 also specifies uniformity requirements. It specifies that individual values of tests at Sr. No. 1 to 3 in Table 3 shall not vary more than 15% from average established from the tests on the 10 preceding samples or of all samples if less than 10. RMC producer should ensure that the uniformity requirements are strictly followed. The format given in Table 3 could be useful for this purpose.

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Table 3: Physical requirements of fly ash conforming to IS 38127 and results of selected tests on samples

Sr. No. 1 2 3 4 Property IS Requirements 34% (max) 320 (min) 4.5 (min) Not less than 80% of control 0.8 (max) Frequency of test suggested by RMCMA Each consignment 3-monthly/ change of source 3-monthly/ change of source 3-monthly/ change of source 3-monthly/ change of source Sample 1 Date Test report Date Sample 2 Test report

Particles retained on 45 µ sieve * Blaine's fineness, m2/kg # Lime reactivity, MPa# 28-day compressive strength, MPa # Soundness, % #

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* Test conducted on each consignment before acceptance # Based on data furnished by supplier by conducting tests in a third-party lab.

8.2.2 Ground-granulated blast-furnace slag (GGBS) 8.2.2.1Ground-granulated blast-furnace slag possesses latent hydraulic properties. For the use of GGBS as a mineral admixture in concrete, no Indian code is available. However, specification for granulated slag for manufacture of Portland slag cement is available (IS 120899). It is therefore suggested that while the physical requirements of GGBS could be in accordance with BS 6699, the chemical requirements could be in line with the Indian code IS 120899. Some of the crucial properties as specified in BS 6699 and IS 120899 are given in Table 4. RMC producer needs to ensure that the supplier gives test certificate satisfying the requirements given in Table 4.

Table 4: Properties of GGBS conforming to BS 6699 and IS 120899 and results of selected tests on samples

Property BS Requirements Date Blaine's fineness (as per BS 6691) Compressive strength, ( as per BS 6691) 7-day 28-day Initial setting time( as per BS 6691) Soundness (Le-Chatellier expansion) (as per BS 6691) Glass content (as per IS 120899) 275 m2/kg (min) 12.0MPa 32.5 MPa Not less than IST of OPC 10 mm (max) 85 % (min.) Sample 1 Sample 2

Test report*

Date

Test report*

* Based on data furnished by supplier by conducting tests in a third-party lab.

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8.2.3

Condensed silica fume

8.2.3.1 Condensed silica fume, also known as micro silica, is a by-product of silicon and ferro-silicon industry. It is an extremely fine material, having specific surface value greater than 15,000 m2/kg.The amorphous silica content should be more than 85%. It is a highly reactive pozzolana. 8.2.3.2 Silica fume should conform to the requirements of IS 153888, which specify the physical and chemical properties. Table 5 gives some of these crucial properties. With a view to ensure supply of good quality silica fume, RMC supplier needs to obtain test certificates from his supplier for each lot of materials that he receives and document the results in the format given in Table 5. Alternatively, it may be a good practice to send a random sample of silica fume to a third-party laboratory and cross check the results obtained with those furnished by the supplier.

Table 5: Properties of condensed silica fume conforming to IS 153888 and results of selected tests on samples

Property IS 15388 8 Requirements Date Specific surface, m2/kg SiO2 content Pozzolanic activity index Moisture content LOI 15,000 (min) 85% (min.) 85% at 28 days 3% max. 6% max. Sample 1 Sample 2

Test report*

Date

Test report*

* Based on data furnished by supplier by conducting tests in a third-party lab.

8.2.4 High reactivity metakaolin (HRM) 8.2.4.1Besides fly ash, GGBS and condensed silica fume, RMC producers can also use another SCMs, namely high reactivity metakaolin (HRM). HRM is obtained by calcination and grinding of pure or refined clay at a temperature between 650-850O C. IS 4562 permits the use of this material as SCM. However, since no Indian standard is available on this material, it would be advisable to refer to the relevant literature on the subject and get the approval of the client/consultant about the quality of the material before use.

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8.3

Chemical admixtures

8.3.1 Ready-mixed concrete needs to be transported over long distances and it needs to be workable to enable proper placement, compaction and finishing. Therefore, use of chemical admixtures, which modify a variety of properties of concrete in its fresh and hardened states, becomes vital. In typical tropical weather conditions prevalent in most part of India, the commonly used admixtures are plasticizers, superplasticiser, and retarders. 8.3.2 Before selecting any brand of admixture, laboratory tests are carried out by RMC producer to establish compatibility of cement-plasticizer/superplasticiser system and also to determine the optimum dosage of admixture, initial slump, extent of slump retention with time, and compressive strengths at various ages as percent of control sample etc. Any adverse effects, e.g. abnormal slump loss, excessive retardation, increased air content, bleeding, etc., observed during these trials should be meticulously documented. Table 6 provides the format for documenting the results of laboratory trials. Incidentally, close liaison with admixture manufacturer is essential during these tests. Once the laboratory trials are over, plant trails may also be carried out. With this, the type of admixture and dosage requirements for different mixes can be frozen. Slight changes in the dosage are made by RMC producer, depending upon the conditions of placement, likely delay in transportation, etc. In case there is any change in the sources of materials, the whole exercise of laboratory trails needs to be repeated. In particular, when the source of cement is changed it may be essential to carry out compatibility trails again. The chemical admixtures used should conform to the requirements specified in IS 910310. Cement-chemical admixture or cement-chemical-mineral admixture compatibility needs to be resolved during the selection of chemical admixture. For this purpose, help can be sought from chemical admixture manufacturer. RMC producer too can carry out certain compatibility tests (Marsh cone or mini-slump cone test) in the plant laboratory and keep the records. The latter would be useful in case certain compatibility problems are noticed.

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Table 6: Results of initial laboratory trials* on chemical admixture

Property Control concrete Concrete with admixture Manufacturer Manufacturer Manufacturer I II III Adverse effects, if any, observed during trials

Name of manufacturer Name of brand Generic type Water content, % of control sample Slump 0 min 30 min 60 min 90 min Setting time, minute Initial Final Compressive strength, % of control sample 1-day 3-day 7-day 28-day Air content, % max over control Observations on cementadmixture compatibility, if any * Laboratory trials can be conducted in plant lab or in a third-party lab (in case facilities are not available in-house)

8.3.3 Admixtures are supplied in large drums. For each batch of admixture the manufacturer needs to provide certificate as per Para 10.1 and 10.2 of IS 910310, giving various properties of the material. The RMC producer should ensure that the material supplied to him matches closely with the one supplied during laboratory trails. It is quite likely that there is variation in the quality of the material being supplied from time to time. To verify this, IS 4562 recommends that the relative density of admixtures shall be checked for each batch and compared with the specified value before acceptance. This practice should be followed. 8.3.4 In addition to this, IS 910310 specifies four more uniformity tests to be carried out on admixtures, Table 7. It may be advisable to get these tests carried out by an independent laboratory and the values so obtained may be compared with those furnished by the manufacturer. IS 910310 does not specify the frequency at which the testing for uniformity can be done. The guideline document however suggests the frequency for the tests as mentioned in Table 7. A record of the test results shall be kept as per the format suggested in this Table.

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Table 7: Uniformity requirement of admixtures conforming to IS 910310 and results of selected tests on samples

Sr. No. Uniformity test Requirements as per IS 910310 Suggested frequency Sample 1 Date Test report Sample 2 Date Test report

1 2

Relative density Dry mat. content of admixture Liquid Solid

Within 0.02 of the value stated by the manufacturer 0.95 T DMC 1.05 T where, T = Manufacturer's stated value in % by mass DMC= Test result in % by mass

Every batch/ consignment

Each new batch before acceptance -

3

Ash content

0.95 T AC 1.05 T where, AC= Test result in % by mass

4

Chloride ion content

Within 10 % of the value or within 0.2 %, whichever is greater as stated by the manufacturer 6 (min.)

Each new batch before acceptance

5

pH

Each new batch

Note: While the test at Sr. No. 1 can be done on each batch/consignment of admixture, the remaining tests mentioned at Sr.No. 2 to 5 can be done in a third-party lab by the supplier and results furnished to RMC producer.

8.4 8.4.1

Water Water used for mixing shall be potable in nature and free from oils, acids, alkalis, salts, sugar, organic materials or any other substances that may be deleterious to steel or the concrete. Permissible limits of impurities in water are specified in IS 4562 (Table 8). Mixing and curing by sea water is not recommended because of the presence of harmful salts in sea water.

Table 8: Permissible limits for solids and results of tests on samples of fresh and recycled water

Sr. No. Solids Permissible limits as specified in IS 4562, max., mg/l 400 Fresh water Sample 1 Sample 2 Date Test Date Test report report Recycled water Sample 1 Sample 2 Date Test Date Test report report

1 2 3 4 5 6

Sulphates as SO3 Chlorides as Cl Reinforced concrete pH Organic Inorganic Suspended matter

500 Not less than 6 200 3000 2000

Note: While the tests mentioned at Sr. No. 1, 2 and 3 can be done quickly at plant with the help of a ready-made kit, the remaining tests (Sr. No. 4, 5 and 6) can be done in a third-party lab at the frequency suggested in IS 49261

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8.4.2

IS 49261 specifies different testing frequencies for mains water and non-mains water. For mains water, the code specifies that testing should initially be done weekly, till six results are obtained, after which testing can be done at three-month interval. For non-mains water, once the source is found satisfactory, testing frequency should be on annual-basis, provided that the chloride ion content does not exceed 0.01%; if the value exceeds this limit, the interval of testing shall be reduced to three-monthly interval. The use of recycled wash water needs to be encouraged from sustainability perspective. However, RMC producer needs to ensure that concrete having satisfying performance is produced with recycled water and that the permissible limits of total chloride and sulphate contents are not exceeded. Incidentally, the test on sulphate and chloride contents and pH can be conducted quickly with the help of a ready-made kit. Other tests (organic, inorganic matter and suspended matter) can be done in a third-party lab at the frequencies suggested in IS 49261. It is suggested that documentation of test results on water should be as given in Table 8. Aggregates Aggregates, which occupy nearly 70-80% volume of concrete, need to be strong, clean, and durable. RMC producer needs large volumes of aggregates on a daily basis. Quite often, he has to depend upon more than one source of aggregates. Before selecting these sources, it is essential to conduct all routine tests on aggregates as specified in IS 38311 for ensuring quality. In addition, certain important properties of aggregates need to be monitored on a continuous basis. IS 49261 suggests testing frequency for different tests on aggregates in Annex B. The basic properties of aggregate related to its mineralogical composition such as crushing value, impact value, abrasion value, soundness, potential alkali-aggregate reactivity, etc will not change much if the aggregate source is the same. Before selecting the source, all these properties are verified. RMC producers should maintain a record of such properties of aggregates obtained from different sources by getting the tests conducted in third-party lab at frequencies suggested in IS 49261. Table 9 suggests a format for such documentation. Quite often, variations are likely in certain other properties such as particle size distribution, moisture content, silt content, water absorption, etc, which are related to techniques used in aggregate processing and external factors. Drawing on the experience and practice followed by some of the leading RMC producers, Table 10 suggests certain frequency of testing for these properties of aggregates. It can be seen from this table that some of the suggested frequencies are stricter when compared with those stipulated in IS 49261. All these properties of aggregates have direct bearing on some crucial properties of concrete, justifying strict frequency of testing.

8.4.3

8.4.4 8.5 8.5.1

8.5.2

8.5.3

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Table 9: Physical properties of aggregates

Property Frequency of testing as per IS 49261(Low test rate) Permissible limits, if any, as specified in IS 38311 Sample 1* Date Test report Sample2* Date Test report

Impact value

As specified

Los Angle's abrasion value Soundness Chloride content Potential AAR

Yearly/ Source change Yearly/ Source change Six monthly 5 Yearly/ Source change

- Not more than 30 for wearing surfaces - Not more than 45 for nonwearing surfaces - Not more than 30 for wearing surfaces - Not more than 50 for nonwearing surfaces

* Based on tests conducted in-house or in a third-party lab.

Table10: Additional physical properties of aggregates

Property Test frequency suggested by IS 49261 Monthly Test frequency suggested by Guideline Weekly or source change Daily twice (three times in monsoon) Monthly 3 monthly 3 monthly 6 monthly 6 monthly 6 monthly Each lot Once in month; or source change 3 monthly 6 monthly 6 monthly 6 monthly Sample 1* Date Test result Date Sample 2* Test result

Gradation Moisture content Silt content for fine aggregates Water absorption Particle density, Bulk density Flakiness Chloride content

* Based on tests conducted at plant lab.

8.5.4 Control on aggregate gradation: It is well known that aggregate grading has an impact on workability, strength and some other properties of concrete. Since RMC producers are constrained to depend upon more than one source of aggregates there is likelihood of a variation in the particle size distribution. The variation would especially be more pronounced in the particle size distribution of river sand. The Guideline therefore recommends weekly check on grading.

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Table 11: Particle size distribution of all-in-aggregates and limits specified in IS 38311

IS sieve size 20 mm Cumulative % passing for 10 mm River sand Crusher fines Cumulative % passing for allin-aggregate IS 38311 limit

Proportion of aggregate in the mix, %

36.00 40 mm 20mm 4.75 mm 600 µ 150 µ

12.00

31.00

21.00 100 95 30 10 0 100 100 50 35 6

8.5.4.1 With a view to verify the extent of variation in particle size distribution, it may be appropriate to carry out the sieve analysis test weekly and record the data of cumulative percentage passing for all-in-aggregates used for the main concrete mixes (for example, M20, M25, M30, M35, M40 etc.) supplied from the plant. The readings may be compared with those of the all-in-aggregate grading limits stipulated by IS 38311. Table 11 shows a typical format for recording the results of sieve analysis. Documentation of such data would be useful in tracking any large variation. If such a variation is evident, suitable corrections may be introduced in the proportions of different aggregate fractions and simultaneously the suppliers may be alerted to rectify supply. 8.5.5 Moisture content: Considerable variation is usually observed in the moisture content of river sand and crushed fines. Such variation in moisture would affect the water-binder ratio and hence strength, if appropriate corrections are not made from time to time in the water content of the mix. This would be possible if these properties are monitored regularly in accordance with the frequency of testing suggested in these guidelines. It is suggested that moisture content in fine aggregates and crushed fines should be monitored two times in a day, and the frequency may be increased to three times in monsoon. Once the moisture contents are known, appropriate correction may then be made in the water-binder ratio. It is essential to keep records of the data on moisture content, possibly in the form of an Excel table or a run chart Silt content: The Guideline recommends that silt content in fine aggregates should be assessed for each lot of supply. River sand is particularly prone to have silt beyond permissible limits. Lots having excessive silt content should be rejected. Control on silt content is essential as an excessive proportion of the same may adversely affect the workability and strength of concrete. It is essential to keep records of the data on silt content. Again, this could be in the form of an Excel table or a run chart.

8.5.6

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9. Sampling and testing of concrete

9.1 Incorrect sampling would adversely affect the results of testing; hence, extreme care should be taken in sampling. It is imperative that the sample of concrete taken from delivery vehicle is `representative'. The point and time of sampling shall be at discharge from the supplier's delivery vehicle or from mixer to the site or when delivered into the purchaser's vehicle. As per Annex C of IS 49261, on reaching the point of placement, the truck should re-mix its contents and allow at least the first one third of a m3 to be discharged before any samples are allowed to be taken. Four incremental 3 samples from the remainder of the load should be then taken, avoiding the last m of concrete. Then the composite sample should be thoroughly re-mixed either in a mixing tray or in the sampling bucket and the required testing should commence only after this. A typical sample report is shown in Table 12. The report provides the time history, sampling location, truck and ticket Nos, etc. The properties of concrete in its fresh state such as slump, unit weight as well as number of cubes made should be recorded. Although filling slump cone and preparing test cubes are fairly simple procedures, the operator needs to follow the procedures meticulously. It is observed that errors in the procedures often adversely affect the test results. It is therefore essential to record the name and signature of the person involved in conducting the tests. The operators involved in carrying out these tests should be trained supervisor, Incidentally, a record of other parameters such as ambient temperature, concrete temperature can also be made in the report.

Table 12: Typical sample report of fresh concrete

Name of Company: ____________________ Date: _________________ Truck No.: ______________ Ticket No.____________ Total quantity:________m3 _____________________________________ Location: ______________________________ Name of client/project: __________________

Time history · · · · · Time batched: ___________ Time arrival at job site: _______ Time discharged: _________ Time sampled: _______ Time tested: _______

Sampled at: · · · End of chute End of pump hose Others

Ambient temperature: ________0C Concrete temperature: ________0 C Slump:_________mm Unit weight: ___________kg/m3

No. of cubes made: __________ Cubes stored at: _____________ Cube prepared by: Mr.____________ Name of authorized person: Mr.___________ Signature: ____________________

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9.2 IS 49261 suggests that sampling may be carried out jointly by the purchaser and the supplier with its frequency mutually agreed upon. The code further states that unless otherwise agreed between the parties involved, the minimum testing frequency to be applied by the producer in absence of recognized ready-mixed concrete industry method of production control, should be one sample for every 50 m3 of production or every 50 batches, whichever is the greater frequency. Table 13 recommends the frequency of sampling for different tests such as slump, compressive strength, density, temperature, etc. Air-entrained concrete is rarely specified in India; however, in case it is supplied, it would be essential to test air content of concrete. In many contracts, the frequency of sampling is stipulated. If the stipulated frequencies are different than what has been shown in Table 13, the former should govern. The size of the sample should generally be not less than 0.035 m3 when it is to be used for strength test. Smaller samples can be taken if used for routine slump tests.

Table 13: Frequency of sampling

QC Test on concrete Slump Compressive strength · · · Density Temperature/Air content · · Frequency Minimum of one sample for each 50m3 or every 50 batches Minimum of one sample (3 test cubes) for each 50m3 or every 50 batches for test at 28 days. Additional sample for early age (3, 7 days) strength test, as mutually agreed As agreed with customer As agreed with customer

9.3 Slump and compressive strength of concrete are two critical parameters to judge concrete's quality. Carrying out slump test and preparation of compression test specimens are fairly simple procedures; however trained operators are needed to ensure that correct procedures are followed. As regards strength test, it is important to follow standard procedures described in IS 119912 and IS 51613 meticulously for making, curing and testing cube specimens. Any deviation from the procedures may adversely affect the final results, highlighting the need to employ trained operators for conducting the tests. Test cubes which are made from fresh concrete are very sensitive to method of handling and storage conditions during the fist few hours. The test specimens shall be stored in moist air of at least 90% humidity and at a temperature of 27 ± 2OC for 24 hours from the time of addition of water to dry ingredients. The specimens shall then be marked and removed from moulds and submerged in fresh and clean water, the temperature of which shall be maintained at 27 ± 2OC. It is essential to employ trained operators for ensuring that adequate precautions are taken during sampling and testing of specimens.

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10.

10.1

Process Control

In addition to ensuring appropriate quality of the input materials in accordance with the guidelines described above, it is essential to exercise strict control on the production process. This can be done in two ways; firstly by ascertaining that the plant and equipment used are in good operational conditions and secondly by ensuring that sufficient efforts are taken in carrying out design of each of the concrete mixes to be supplied, following well established methods/norms. Upkeep of production facility

10.2

10.2.1 RMCMA certification through a third-party audit certainly provides guarantee to the user that the certified production facility possesses capabilities to produce quality concrete. This certificate is however based on the commitment provided by the producer that he would adequately maintain the production facility in accordance with the provisions of RMCMA Check List (QC Manual Part-I). The producer can demonstrate this by carrying out routine maintenance of storage, handling, batching, mixing and transporting equipment as well as through regular calibration of weighing equipment at desired frequency and keeping a proper record of the same. Based on the practices followed by some of the leading RMC producers, Table 14 gives the suggested frequencies of maintenance/calibration checks for different components of plant and equipment. It may be mentioned that the frequencies suggested in this Table are either similar or stricter than those prescribed in IS 49261.

Table 14: Production control: Suggested frequencies of inspection, maintainance/calibration

Items Check for Frequency prescribed by IS 49261 Frequency prescribed by RMCMA Weekly Daily Weekly Daily Weekly Monthly Monthly Monthly Monthly Quarterly Plant inspection Date Operator name and sign Date Operator name and sign Observation of operator, if any

Cementitious materials Aggregate stockpile Conveyor belts and rollers Central mixer Trucks Scale calibration for all weighing and measuring equipment Water meters Admixture dispensers Gear boxes and oil baths

Visual Inspection for weather-tightness and leaks Visual Inspection for segregation and contamination Visual Inspection for wear and alignment Visual Inspection of blades and built up Visual Inspection of blades and built up 1.Mechanical/knife edge systems 2.Electrical/ load cell systems Calibration Calibration Oil change

Weekly Weekly Weekly Weekly 2 monthly 3 monthly Monthly Monthly Quarterly

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10.2.1

It is essential that proper records of routine maintenance and calibration are kept by RMC producer. The records need to be updated on a regular basis. With a view to ensure accountability, it would be a good practice to include the name and dated signature of person carrying out inspection and calibration (see Table 14). Concrete mix design In India, a majority of concrete supplied by RMC producers would fall in the category of `designed mixes'. Most of the clients specify their requirements of workability and strength along with the requirement of pumping or otherwise. A responsible RMC producer usually ensures that the code-specified durability requirements (in terms of minimum cement content, maximum free water-cement ratio, etc.) are met with. Sometimes, durability requirements and the allowable maximum size of aggregate are specified by certain clients. Based on these requirements, the RMC producer carries out mix design in his (or third-party) laboratory, involving casting and testing trial concrete mixes and optimizing the mix proportions. It is quite likely that the RMC producer has supplied mixes with similar design earlier, in which case the producer can furnish actual field data. The details of the finalized mixes are furnished to the client, who is required to approve the same before supply can commence. It is suggested that the details of the designed mixes should be maintained in a standard format as given in Table 15. These details should be furnished to the client on demand. The format is adopted from Annex D of IS 49261, which has been slightly modified to suit the requirement of these Guidelines. Besides the contents of cement and mineral additives, and free water-cement ratio, the Table also contains information on slump at pour site as well as certain additional desirable information. Separate data sheet may be kept for separate clients and for separate sites of the same client or different clients. While the RMC producer is free to adopt any rational method of designing concrete mixes, it would be a good practice to adhere to the various code-specified requirements, especially those related to durability of concrete (minimum cementitious content, maximum free water-binder ratio, etc.).

10.3 10.3.1

10.3.2

10.3.3

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Table 15: Concrete mix design information

Name of RMC Producer: _____________________________________________________ Name of Client/Contractor:___________________________________________________ Site: ____________________________________________________________________ Mix code Characteristic strength, N/mm2 Target strength, N/mm2 Minimum cement content, kg/m3 (if specified) Mineral additives, kg/m3 · · · · Pulverized fuel ash Slag Silica fume Others (mention type)

Cement type and grade Nominal maximum aggregate size, mm Maximum free water-binder ratio Aggregate/cement ratio Target workability at plant, (Slump, mm) Target workability at site, (Slump, mm) Maximum temperature of concrete at the time of placing Class of sulphate resistance ( if applicable) Exposure condition ( if applicable) Class of finish ( if applicable) Mix application Method of placing Any other requirements (if applicable)

Laboratory compressive strength, MPa 7-day 28-day Source: Adapted from IS 49261

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11.0 Control Charts

11.1 There is an inherent variability in the properties of various concrete ingredients, in the production process and the testing procedures. Although RMC producers take maximum possible care to minimize variability, the same cannot be avoided. It is however important to quantify the variability and also to identify as to whether it can be attributed to the materials, the production process or the test methods. The variability could be due to "chance" causes or "assignable" causes. While chance causes can be attributed to the normal variability of the process, assignable causes can be eliminated or minimized, thereby reducing the overall variability. 11.2 Control charts can be useful in detecting and monitoring the variability. Such charts can also be useful in distinguishing chance causes from assignable causes and therefore, they can be used to decrease variability by eliminating the latter. The charts can also form a permanent record of quality. Additionally the charts can also be used as a basis for changing specification limits, if found essential. 11.3 The guidelines strongly recommend use of control charts to monitor QA and QC of concrete.

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12.0 Properties of Fresh Concrete

12.1 Workability of concrete 12.1.1 Workability is a broad term which encompasses a range of properties of fresh concrete such as consistency (fluidity), mobility (ability of concrete to move around the reinforcement and in restricted areas), compactibility, finishibility and pumpability (for pumped concrete). Evaluating workability is therefore not easy in view the composite nature of the property. The degree of workability varies depending upon the type of construction and method of placing, compacting and finishing. The IS 4562 provides guidance on the range of workability requirements for different placing conditions and applications (Table 16). Consistency of fresh concrete is considered to be a close indication of its workability and slump test has been the most widely used test for ascertaining consistency and hence workability. However, the IS 4562 suggests that slump test is preferable only for slumps varying from 25 mm to 150mm. For applications requiring very low slumps (lower than 25mm), the code recommends use of compacting factor test. Similarly, for applications requiring very high slumps (higher than 150mm) it recommends use of flow table test. For a majority of concrete supplied by RMC producers, slump test is the most commonly-used test.

Table 16: Degree of workability for different working conditions

Placing conditions Blinding concrete; Shallow sections; Pavement using pavers Mass concrete; lightly reinforced sections in slabs, beams, walls, columns; floors; hand placed pavements; canal linings; strip footings. Heavily reinforced sections in slabs, columns, beams, walls; slip-form work; pumped concrete Trench fill; In-situ piling Tremie concrete Source: IS 4562 Degree of workability Very low Slump, mm Use compacting factor test as per IS:119912

Low

25-75

Medium

50-100 75-100 100-150 Use determination of flow test as per IS: 910310

High Very High

12.1.2 The IS 49261 specifies the following tolerance limits of workability as criteria for acceptance: · · Slump: ± 25 mm or ± 1/3rd of the specified value whichever is less Compacting factor: ± 0.03 for specified value 0.9; ± 0.04 for specified value 0.9 0.8 ± 0.05 for specified value 0.8 Flow test: Acceptance criteria to be established between the supplier and purchaser.

·

12.1.3 The test for workability needs to be performed upon discharge from producer's delivery vehicle on site or upon discharge into the purchaser's vehicle. On some occasions, lack of preparedness on the part of purchaser at construction site may result in delay of placement. RMC producer will

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be respon nsible for ma aintaining the slump with the perm hin missible rang for a perio of 30 min ge od nutes, 1 starting fr rom arrival o transit mi of ixers at job s site. Howeve after 30 m er, minutes, the IS 4926 cl e learly states that the respons t sibility for de passes o the purch elay on haser. 12.1.4 Slump tes is somewh a crude measure of workability yet it is q 4 st hat f y; quick and he ence remain the ns much spe ecified and accepted m method. Slum of conc mp crete is quit sensitive to a variety of te environmental and ot ther factors s such as conc crete temper rature, ambi ient tempera ature, surface rate e of evapor ration, chan nges in grad ding, batch mass diffe erences, adm mixture dosa age, presenc of ce mineral admixtures o otherwise, variation in air conten variation in testing, e It would be a or , n nt, etc. d good prac ctice to reco the value of slump in Microsof Excel form and dra a run cha A ord es ft mat aw art. typical ex xample is sh hown in Fig 1. Such g g graphs would be useful in ascertain d ning the lev of vel control ex xercised by R RMC produc in contro cer olling the var riation in wo orkability.

Fig 1 Typical vari iation in the slump of a p pumpable mix (specified v value: 100 m mm)

12.2

Density of concrete o

12.2.1 The plast density ( tic (unit weight) of conven ) ntional norm mal-weight concrete vari from 2250 to ies 2450 kg/m3. It varies depending upon the v m s g variation in the density of different ingredients the t s, amount of entrapped and entrain air (if ai ned ir-entraining agents are used), the m g maximum si of ize e nt g gate volume and e aggregate and water and cemen contents in the mix. Increasing the aggreg reducing the cement p t paste would increase the density of c concrete. 2. ixed concret is measure on the ba of volum The volu te ed asis me. ume of fresh concrete ca be h an 12.2.2 Ready mi determine by dividing the total weight of a batched materials by the averag unit weig or ed all y ge ght plastic de ensity of co oncrete dete ermined in accordance with IS 1 e 119912. Som metimes, the is ere likelihood of a discre d epancy in the concrete o ordered and that actually supplied. T y There could be a d variety of reasons fo this discr f or repancy. The include wastage an spillage o concrete, over ese nd of excavation, miscalcul lations in for volume, deflection o distortions of forms, s rm or s settlement o wet of mixes, los of entrain air, etc. S ss ned Such differen can be reconciled if plastic dens of concr is nce f sity rete monitored regularly. d 12.2.3 While car rrying out m design, th plastic de mix he ensity of designed mix is measured and tallied with d d the theore etical densit However since there is a likelihood of a c ty. r, change in th plastic de he ensity owing to minor adjustments that the RMC producer is required to carry out i the produ t in uction process, it would be a good practice to measu the plasti density at regular inte t ure ic t erval so as en nsure

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that the qu uantities sup pplied match orders. The plastic den h e nsity measur rement can b done by f be filling a containe of known volume wi fully com er n ith mpacted concrete and tak king the ma of concre in ass ete 12 that volum by follo me owing proced dures detailed in IS 1199 . In cas a weigh bridge facility is se available at the plan it would be a good practice to weigh tran mixers before and after nt, o nsit delivery. 12.2.4 Many RM produce prefer to measure th densities of cubes (h 4 MC ers o he hardened co oncrete dens sities) before tes sting them fo compress for sive strength This can s h. simply be do by findin the volum of one ng me cubes by water displa acement met thod and div viding the m mass of cubes in air by th volume. F 2 s his Fig shows a ty ypical variat tion in the c cube densitie taken from the record of a RMC facility. In case es m ds C n certain cu compress strength show low values, it w ube sive hs would be advisable to che the density of eck the corres sponding cu samples if the den ube s; nsities of th cubes are lower tha the theoretical he e an density, th low value could be a he es attributed to operator's s o sampling err rors.

Fig 2 Typical vari iation in densities of cube es

12.3

Temperat ture of conc crete

12.3.1 In most parts of India tropical we a, eather preva necessitating adoption of adequate precautio ails, onary with eather concre eting practic Absence of adequa measures may ces. e ate s measures associated w hot we apid loss of workabilit accelerat stiffenin of concre poor co f ty, ted ng ete, ompactibility and y lead to ra finishibili and crac ity, cking of con ncrete owing to plastic and/or therm shrinkag The latt at g mal ge. ter, times, becomes a po oint of disp pute between RMC pro n oducer and contractor/c clients. To a avoid adverse effects of ho weather, b e ot both RMC producer an the contr nd ractor need to take adequate precaution nary measur res. While t RMC pr the roducer needs to design a mix hav n ving low he of eat hydration, contractor needs to tak a number of well-esta ke ablished prec cautions in p placing, finishing and curin of concret As far as RMC prod ng te. s ducer is con ncerned, he n needs to des sign the con ncrete mix using a combina g ation of OPC and supplementary ce C ementitious materials or blended ce r ement for reduci the heat of hydratio In additi ing t on. ion, the agg gregate stock kpiles in the plant shou be e uld covered to avoid dire exposure to sun and water shoul be sprink o ect e ld kled on the s stockpile to bring down the temperature Some RM producer use chille water or ice flakes to bring dow the e. MC rs ed o wn temperatu of mixing water during hot summ months. Many consu ure g mer ultants/clien stipulate u nts upper limit on th temperatu of concre at pour. D he ure ete During hot w weather cond ditions, it is always advi isable

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to keep the temperature of concrete low. This guideline recommends 350C as the upper limit of temperature of concrete at pour. 12.3.2 It would a good practice to monitor and record both the ambient and concrete temperatures during pour. The recording of temperatures could be in the form of a run chart (see Fig 3). Such chart would give quick idea about the extent of variation of pour temperature and would be useful in the evaluation of the possible reasons for plastic shrinkage and/or thermal shrinkage cracking, if such cracking is witnessed. Such records would also be providing assurance to customers about the producer's ability to control concrete temperature.

Fig 3 Variation in temperature of fresh concrete

12.4

Air content of fresh concrete

12.4.1 In most parts of India, freeze-thaw conditions do not prevail; therefore it is not necessary to use air-entrained concrete. However, in certain places in northern and north-eastern part of India, if it becomes essential to use air-entrained concrete to counter the effects of freeze-thaw conditions, it would be essential to measure and monitor the air content in concrete.

- 38 -

13

13.1 13.1.1

Propert of Hard ties dened Conc crete

Strengt of concre th ete Strength of concrete is used as a basis for a h e acceptance in civil engin n neering cont tracts. It is b both a structura attribute a a measur of develo al and re opment of hy ydration. In a large majo ority of cont tracts, compres ssive strength of the cubes made, cur and teste at 28 days in accordan with IS 51613 h red ed s nce is the si ingle most a acceptance p parameter. T This is becau testing o strength is relatively easy. use of Furtherm more, many properties o concrete s of such as elast modulus, flexural str tic rength, shea and ar bond str rengths, ca be deduce from com an ed mpressive str rength, after appropriate correlation are r e ns establish hed.

13.1.2 While th strength o concrete a 28 days ha emerged a a basis for contract sp 2 he of at as as pecifications it is s, too long for RMC p g producer to wait for tak king action t rectify pr to roduction pr roblems. It i too is long also for contra actors and sp pecifiers to w for taking decisions for removi forms or prewait s ing r g or er ion. stressing concrete, o to continue with furthe constructi 13.1.3 To over rcome this, u is made of the rela use e ationship bet tween early-age and 28-day strengt to ths allow re emedial actio to be taken quickly. For example, RMC pro on oducers and contractors often use 7-da 3-day or even 1-day strength as a tool to est ay, timate the li ikely later-ag strengths. It is ge however important to establish the relation r h nship between early-age and 28-da strengths for a e ay particula cementitio and aggr ar ous regate combi ination in us and to mo se, onitor the rel lationship. A typica chart depicting the v al variation in 7 7-day and 2 28-day streng gths is show in Fig 4. The wn chart sh hows that the actual 28e -day strength of concre samples are more th the spec hs ete han cified strength of 25 MPa. Documenta ation of com mpressive stre ength data in such a form gives a good n mat idea abo the variat out tion in streng values at a glance. gth t

13.1.4 4

Fig 4 Typical variat tion of 7-day a 28-day str and rengths of M2 concrete 25

- 39 -

13.2 13.2.1

Standard deviation For the effective implementation of QA-QC programme, two main tasks before any RMC producer are: avoidance of failures and attainment of low variability in the test results. While every RMC producer would like to keep a reasonable margin of safety to avoid failures, he would also like to have the margin to be as low as possible, so as to achieve economy in production. For designed mixes, the target mean strength is kept higher than the specified strength by a certain design margin as given below: Target strength = specified strength + k s (design margin)

where, k = a constant which depends upon the proportion of results permitted to be below specified strength s = standard deviation. In most of the contract specifications in India, the permissible percentage below which no results are expected to lie is generally taken as 5 %. The k value derived mathematically from statistical tables for 5% failure rate is 1.64. While designing concrete mixes, when no initial data is available, code-specified values of standard deviation -- which are dependent on the degree of control at site as well as the grade of concrete -- are taken in calculations (Table 8 of IS 4562). When more than 30 strength test results are obtained, the actual standard deviation is calculated for each mix and compared with the assumed values. Higher standard deviation indicates lower levels of controls. The stricter the QA-QC at the plant, lower will be standard deviations. Thus, monitoring and controlling the variation in standard deviation of compressive strength of concrete mixes could be a crucial parameter in the QA-QC of concrete. The Guideline therefore suggests that standard deviation of major concrete mixes supplied by the RMC facility should be evaluated and monitored on a regular basis. However, the standard deviation should be calculated for a minimum of 30 results.

13.2.2

13.2.3

13.2.4 The standard deviation of M20, M30 and M40 concrete mixes from a RMC facility for three consecutive months is shown in Fig 5.

M25 M30 M40

Standard deviation, MPa

6 4 2 0

June July Month Aug

Fig 5 Actual standard deviation of major mixes from a typical RMC facility

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13.3

Acceptan criteria for compre nce essive streng gth

13.3.1 The IS 4562 provide guidance on the acceptance criter Accordi to the co 4 es ria. ing ode, the con ncrete shall be deemed to comply with strength re h equirements when both the followin condition are ng ns met: · the mean strength determined from any gr roup of four non-overlap pping consec cutive tests co omplies with the appropr h riate limits o column 2 in Table 17; of ;

In ndividual results, N/mm2 s, ( fck ­ 3) N/mm2

Table 17: Charac e cteristic comp pressive stren ngth complia ance requirem ment

Spec cified grade M 15 or o above Mean of the gr roup of 4 non-o overlapping cons secutive test results, N/ /mm2 fck + 0.825 x established stan ndard deviation (rounded off to nearest 0 N/mm2) 0.5 Or mm is fck + 3 N/m 2, whichever i greater

Source Table 11 of IS 4562 (amendme 3 of August 2 e: S ent 2007)

13.3.2 2

Typical variation in the 28-day strength as well as th mean valu of a gro of four nonn y s he ues oup overlapp ping consecu utive test re esults can be etter be mon nitored with the help of an Excel-b h f based chart an the same can serve a record. A typical char is shown in Fig 6. Fr nd as rt rom this gra it aph would be easy to im mmediately id dentify any s shortcoming in the test r g results. For e example,in F 6, Fig no single test result falls below the limit of ( fck ­ 3) (22 MPa). Thus, it can be co oncluded tha the at 2 30 test results fulfills the accepta ance criteria set by IS 45 . a 56

Fig 6 Variation of 28-day stren f ngth of concrete along w the varia with ation in the m mean Of 4 n non-overlapp ping consecu utive test resu ults.

13.3.3

It would be a good practice to feed the 28 d d 8-day compr ressive stren ngth data in Excel shee and et prepare charts simila to those in Fig 6 for th important concrete m ar n he t mixes supplie by the pla ed ant.

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14.0

Special QC Techniques

In addition to whatever has been recommended above, RMC producers are free to adopt special quality control techniques in their day-to-day work. In fact, one should welcome and encourage such efforts on the part of RMC producers. Some such techniques include: internal audit, Cusum technique, failure analysis.

14.1 14.1.1

Internal quality audits report Many leading RMC producers have developed rigorous internal quality norms and follow well defined practices to monitor and control quality of input and output materials. In some of these companies, there is a systematic procedure of reporting quality parameters within the organization. Quite often, these reports may contain some cost-sensitive information. It is suggested that after filtering out commercially-sensitive information, the remaining information may be incorporated in the quality document and the same may be shared with the customers. Cusum technique The "Cusum" technique which was developed in 1960s, was applied to RMC in the 1970s. It became a widely-used technique in RMC in the UK and many other countries. The British Standard, BS 5703, published a guide on the technique in 1980 and the Quality Scheme for Ready Mixed Concrete (QSRMC), UK, adopted it in 1984.

14.2 14.2.1

14.2.2 The essential principle is that differences between results and their target values are calculated and added cumulatively to form a cumulative sum (cusum). When this cusum is plotted graphically against the sequence of results, a visual presentation of trends relative to the target level is produced. 14.2.3 The Cusum system can be used for monitoring trends in mean strength, standard deviation and the relationship between early-age and 28-day strengths. It assists in detection of changes in these properties and indicates when action should be taken to increase the probability of meeting the specification or to reduce the materials cost. 14.2.4 There are following three types of cusum systems: · Cusum M ­ Mean strength Keeps track of the difference between the target mean strength and the estimated mean strength (on the basis of the 7 day result) · Cusum R ­ Range Keeps track of the range of values of the mean strength and monitors the standard deviation. · Cusum C ­ Correlation Keeps track of the differences between the estimated mean strength and the achieved mean strength at 28th day. 14.2.5 Some leading RMC producers have developed their own variant of the cusum system. Certain other producers use standard software packages based on cusum principles. It is recommended that some of the crucial data on monitoring cusum, which is not price-sensitive, may be included in the QC document for building confidence amongst customers.

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15.

Key Personnel

15.1.1 The success of any QA-QC system would be dependent upon the abilities of key personnel in the production facility -- in particular, their level of knowledge in concrete technology, managerial ability, length of experience and training undergone. It would be a good practice to include the names and other details of key plant personnel in the QC document. Besides educational qualifications, the extent of experience in RMC sphere may also be included. Further, any recent in-house or external training undergone by the plant personnel should also be incorporated in the document. Table 18 suggests a format for such documentation.

Table 18: Names, designation and experience of key plant personnel

Sr. no. 1 Name of personnel ABC Designation Plant-in-charge Educational qualification BE(Civil), Dip. in Business management Dip. in Civil Engg. Experience -3 years in RMC field - 2 years in construction - 7 years in RMC field Training - Distinction in CGLI Part II examination in 2007 - In-house training in management 2006 -Credit in CGLI Part-I examination - In-house training in safety and maintenance in 2007 - NCB training in concrete technology in 2005 - In-house training in QA-QC - Certificate course from recognized institution - In-house training

2

XYZ

Production-incharge

3

MNR

QC In-charge

BE (Civil)

2 years in RMC field 3 years in customer service 1 year site engineer 5 years of lab experience

4

VBS

Supervisor

B Sc

- 43 -

Section II

Typical Example Sample QA-QC Document (Needs periodic updating)

- 44 -

Introduction

This I of the Guidelines presents QA-QC document of a typical RMC production facility. The document is based on the discussion in of the Guidelines and is in the form of a tabular and graphical report. It is recommended that each RMC facility should have its own QA-QC document, prepared with the help of its own data. The tables and graphs included in this section can serve as a guide to prepare such document. As pointed out in the Preface, this document lays down the basic framework which includes minimum necessary benchmarks. Each RMC facility is free to follow its own format and framework; however, the minimum benchmarks included in this document must be followed. Freedom is also available to the RMC producer to excel over the minimum benchmarks suggested here. One of the most important aspects of the document is that it cannot be a static or one-time document. It needs to be continuously updated. The best way to do this is to keep the records and test results in Microsoft Word or Excel format and update the records periodically (preferably daily) as more and more data become available. Thus, a customer can be presented with the latest data at any moment. What is also important is the fact that some of the tables and graphs in the report can serve as a handy tool for the Company management to judge the performance of a particular facility. As mentioned in of this document, it would be appropriate to include the following information by each Company in its QC Manual. · · · · Information about the history of the Company, its network and management Quality policy of the Company Management responsibility and commitment Any other information that the Company thinks relevant for this document.

- 45 -

S-1 Sources of Ingredients

Table S-1: Sources of different ingredients of concrete

Material Type/ Class OPC Cement PPC PSC Other Fly ash Slag Silica fume Water Ice Fine aggregate Coarse aggregate Quarry fines W.R. Agent H.R.W.R.A. Retarder Others River sand Man. sand 40-mm down 25-mm down 12.5-mm down Siliceous Calcareous 43 grade 53 grade ABC DEF GHI ABC ABC Quarry A Quarry B Quarry B Quarry B ABC XYZ Source Name of supplier / Factory / brand Location XXX YYY XXX XXX XXX XXX XXX X XX XXX YYY -

- 46 -

S-2 Monitoring Quality of Ingredients

S-2.1 Cements Table S-2.1: Selected properties of cement*

Property Date of testing Type of cement Manufacturer I Oct. 15, 2007 PPC Provisions of IS 1489: (Part I)5 Fineness, m2/kg Compressive strength, MPa 3-day 7-day 28-day Setting time, minutes. Initial Final Soundness, mm Loss on ignition, % % of mineral admixture (fly ash or slag) in PPC or PSC 15-35 % fly ash 30 (min) 600 (max) 10 (max) 130 210 1.00 1.65 22 % fly ash 30 (min) 600 (max) 10 (max) 4 (max) 135 185 1.00 2.08 Nil 35-70 % slag 30 (min) 600 (max) 10 (max) 118 178 0.37 1.35 50% slag 16 22 33 39.17 48.36 68.74 27 37 53 41.00 49.00 59.00 16 22 33 28.19 39.59 59.14 300 (min) Test results Manufacturer II Oct. 22, 2007 OPC 53 grade Provisions of IS 122694 225 (min) Test results Manufacturer III Oct. 29, 2007 PSC Provisions of IS 4556 225 (min) Test results 388

416.20

306.00

* Results based on the test certificate provided by cement manufacturers.

S-2.2 Fly ash Table S-2.2: Physical requirements of fly ash conforming to IS 38127 and results of selected tests on samples

Sr.No. Property IS 38127 Requirements Date 1 2 3 4 5 Particles retained on 45 µ sieve Blaine's fineness Lime reactivity 28-day compressive strength Soundness 34% (max) 320 m2/kg (min) 4.5 MPa (min) Not less than 80% of control 0.8 % (max) Oct. 10 Oct. 10 Oct. 10 Oct. 10 Oct. 10 Sample 1 Test report 12.70# 416* 6.80* 44.40* 0.50* Date Oct. 22 Oct. 22 Oct. 22 Oct. 22 Oct. 22 Sample 2 Test report 17.00# 425* 6.40* 46.20* 0.50*

# Results based on test done at plant * Results based on manufacturer's certificate

- 47 -

S-2.3 Ground granulated blast furnace slag Table S-2.3: Properties of GGBS conforming to BS 6699 and IS 120899 and results* of selected tests on samples

Property BS 6699 / IS 12089 Requirements Date Blaine's fineness Compressive strength, 7-day 28-day Initial setting time Soundness (Le-Chatellier expansion) Glass content 275 m2/kg (min) 12.0 MPa 32.5 MPa Not less than IST of OPC 10mm (max) 67% (min.) Feb. 6 Feb. 6 Results of tests*

Test report 385 36.15 46.45 211 min 0.00 93

Date Mar 23 Mar 23

Test report 373 35.55 43.50 223 min 0.00 98

Feb. 6 Feb. 6 Feb. 6

Mar 23 Mar 23 Mar 23

* Results based on the test certificate provided by cement manufacturer.

S-2.4 Condensed silica fume Table S-2.4: Properties of condensed silica fume conforming to IS 153888 and results* of selected tests on samples

Property IS 153888 Requirements Date Specific surface, m2/kg SiO2 content, % Pozzolanic activity index Moisture content LOI 15,000 (min) 85% (min.) 85% at 28 days 3% max. 6% max. Aug 31 Aug 31 Aug 31 Aug 31 Aug 31 Results of tests*

Test report 18,000 90 negligible 4.6

Date Sept. 15 Sept. 15 Sept. 15 Sept. 15 Sept. 15

Test report 17,500 87 negligible 4.2

* Results based on the test certificate provided by manufacturer.

- 48 -

S-2.5 Chemical admixtures Table S-2.5.1: Results of initial laboratory trials on Chemical admixture

Property Control concrete Concrete with admixture Manufacturer Manufacturer Manufacturer I II III XXX AAA HRWRA 12 YYY BBB HRWRA 16 ZZZ CCC HRWRA 14 Adverse effects, if any, observed during trials

Name of Manufacturer Name of brand Generic type Water content, % of control sample Slump 0 min 30 min 60 min 90 min Compressive strength, % of control sample 1-day 3-day 7-day 28-day

40 0 0 0

140 120 120 -

160 145 110 -

140 120 120 -

18.28 22.93 35.11

17.77 21.87 36.02

18.88 23.14 37.12

17.37 20.88 34.12

Sample from Manufacturer III produced strengths lower than the control strengths at 3, 7 and 28 days. This sample was therefore rejected. The 3 and 7 day strength for sample of Manufacturer I were lower than the control. This sample was also rejected. Sample from Manufacturer II was found suitable.

Air content, % max over control Observations on cementadmixture compatibility

Not tested

Not tested

Not tested

Not tested

-

No incompatibility problems noticed

No incompatibility problems noticed

No incompatibility problems noticed

Dosage of 1 % by weight of cementitious material was selected based on manufacturer's recommendation; no adverse effects noticed.

Control mix details: PPC: 380 kg; Aggregates: 651 kg (20 mm), 351 kg (10 mm), 421 kg (CRF), sand: 421 kg, water: 254 lit.

- 49 -

Table S-2.5.2: Uniformity requirement of admixtures conforming to IS 910310 and results of selected tests on samples

Uniformity test Requirements as per IS 91038 Suggested frequency Test values at the time of acceptance 1.25 Test values during use Sample 1 Date Aug 07 Test report 1.24# Sample 2 Date Aug 08 Test report 1.266#

Relative density Dry mat. content of admixture

Within 0.02 of the value stated by the manufacturer 0.95 T DMC 1.05 T where, T = Manufacturer's stated value in % by mass DMC= Test result in % by mass 0.95 T AC 1.05 T where, AC= Test result in % by mass Within 10 % of the value or within 0.2 %, whichever is greater as stated by the manufacturer 6 (min.)

For every drum before use

Each new batch before acceptance Each new batch before acceptance Each new batch

48.0 -

-

48.29* (0.6%) 0.004*

-

48.84 (1.75%) 0.091*

Ash content Chloride ion content

-

-

pH

7.26

-

7.05*

-

7.89*

* Results based on manufacturer's certificate.. # Results based test conducted at plant.

S-2.6 Water Table S-2.6: Permissible limits for solids in water and results of tests on samples of fresh and recycled water

Solids Permissible limits as specified in IS 4562, max., mg/l 400 2000 500 Not less than 6 2000 200 3000 Mar 9 Mar 9 Mar 9 Mar 9 Fresh water Sample 1 Date Test report 70 124 124 6.8 1500 145 2500 June 8 June 8 June 8 June 8

2

Sample 2 Date Test report

Sample 1 Date

Recycled water Sample 2 Test report 200 450 450 Date Test report

Sulphates as SO3 # Chlorides as Cl · · pH Suspended matter* Organic* Inorganic*

#

Mar 9 Mar 9

June 8 June 8

950 2800 2800 7.4 223 66 5800

Mar 9 Mar 9

June 8 June 8

200 490 490

Plain concrete R.C.

Mar 9 Mar 9 Mar 9 Mar 9

6.9

June 8 June 8

8.1

N.A. N.A.

June 8 June 8

N.A. N.A.

Note: The underlined values being higher than those specified in IS 456 , the consignment from which Sample 2 was taken was rejected. * Results based on manufacturer's certificate.. # Results based test conducted at plant.

- 50 -

S-2.7 Aggregate 7 es Tab S-2.7.1: Physical prop ble P perties of agg gregates

Pro operty Frequency o of testing as pe IS er 49261(Low t test rate) As specifi ied Permiss sible limits, if an as ny, specified in IS 38311 d Date D - Not mo than 30 for w ore wearing surfaces s - Not mo than 45 for n ore non-wearing surfaces s - Not mo than 30 for w ore wearing surfaces s - Not mo than 50 for n ore non-wearing surfaces s Sampl 1 le Test T report* 20.7% 25.6% 8.5% (MgSO4) Negligible Innocuous

Im mpact value

Los Angeles abr rasion value Sou undness Ch hloride content Pot tential AAR

Yearly/ Sou urce change Yearly/ Sou urce change Six month hly 5 Yearly y/ Source cha ange

* Based on tests condu ucted in third-par lab. rty

S-2.7 Aggrega gradatio 7.1 ate on

Tab S-2.7.1.1: Cumulative % passing for a ble C aggregates use for M 25 m with IS 38311 limits ed mix 3

(Agg gregate proportion: 20mm: 10m river sand: c mm: crushed sand = 3 36:12:31:21) IS I sieve, mm 20 mm 40 20 4.7 75 0.6 60 0.1 15 36.00 30.10 0.11 0.00 0.00 10 mm 12.00 12.00 1.27 0.00 0.00 Cumulative perc C cent passing River sand 31.00 31.00 23.16 4.50 0.47 Crushed sand 21.00 21.00 19.80 6.20 2.90 All-inaggregates 100.00 94.00 44.00 11.00 3.00

1 IS 38311 limits

Lower limit 100.00 95.00 30.00 10.00 0.00

Upper limit 100.00 100.00 50.00 35.00 6.00

Fig S S-2.7.1.1 All-in n-aggregate gr rading curve f aggregates used for M 2 for s 25 11 mix w upper an lower limits as per IS 383 (graphical representatio of Table S-2 with nd s 3 on 2.7.1.1)

- 51 -

Table S-2.7.1.2: Cu umulative % p passing for agg gregates used for M 40 mix with IS 38311 limits

(Aggre egate proportion : 20mm: 10mm river sand: cr m: rushed sand = 41 1:13:32:14) IS sie eve, mm m 20 mm 40 20 4.75 0.60 0.15 41.00 34.28 0.12 0.00 0.00 10 mm 13.00 13.00 1.38 0.00 0.00 Cum mulative percent passing River sand 32.00 32.00 23.90 4.64 0.48 Crushed C sand s 14.00 1 14.00 1 13.20 1 4.97 4 1.93 1 All-inA ag ggregates 100.00 93.00 39.00 10.00 2.00 IS 38311 lim mits Lo ower limit 10 00.00 95 5.00 30 0.00 10 0.00 0.0 00 Upp limit per 100 0.00 100 0.00 50.00 35.00 6.00

Fig S-2.7.1.2 All-in-aggregate gra ading curve fo aggregates u or used for M 40 0 11 1 mix w upper and lower limits as per IS 383 (graphical r with d representation of Table S-2. n .7.1.2)

e A hysical prope erties of aggr regates Table S-2.7.1.3: Additional ph

Proper rty Test frequency suggested by IS 49261 Monthly Test frequency suggested by Guideline Date D Weekly or sour change rce Daily twice (thr times in ree monsoon) Monthly Each lot Sample 1* S Test res sults

Gradat tion Moistu content ure Silt con ntent for fine aggreg gates Water absorption, % Bulk d density, kg/m3 (Uncom mpacted) Bulk d density, kg/m3 (Comp pacted) Flakine index, % ess

See Tables S-2.7 7.1.1 and S-2.7.1.2 See graph shown in Fig S-2.7.2 See graph shown in Fig S-2.7.3 M1 M2 1.6 1468 1590 7.76 Sand d 3.15 1858 8 1910 0 CRF 3.9 1580 1690 -

3 monthly 3 monthly 6 monthly 6 monthly

3 monthly; or so ource change 3 monthly; or so ource change 3 monthly; or so ource change 3 monthly; or so ource change

Oct.15 O Oct.15 O Oct.15 O Oct.15 O

2.4 1492 1615 8.59

- 52 -

S-2.7 Moisture content 7.2 e

Fig S-2.7.2 Variat tion in moistu content o fine and co ure of oarse aggreg gates and cru ushed sand 2.7.3 Silt conten nt

Fig 2. .7.3 Variation in silt cont tent of river s sand as percent by volum me

- 53 -

S-3 Sampling and testing of concrete

Table S-3: Typical sample report of fresh concrete

Name of Company: X Y Z Location: Mumbai Name of client/project: A B C Ticket No.: X Y Z 1111 Total quantity: 25 m3 Time history · · · · · Time batched: 15.30 hour Time arrival at job site: 16.45 hour Time discharged: 17.00 hour Time sampled: 17.05 hour Time tested: 17.10 (slump) No. of cubes made: 04 Cubes stored at: _____________ Cube prepared by: Mr. A B C Name of authorized person: Mr XYZ Signature: Signed by X Y Z Sampled at: · · · End of chute End of pump hose Others Date: September 28, 2007 Truck No.: MH 1111

Ambient temperature: 300C Concrete temperature: 320 C Slump: 120 mm Unit weight: 2475 kg/m3

- 54 -

S-4 Process Control

S-4.1 Inspection report of production facilities Table S-4.1: Production control

Items Check for Frequency prescribed by IS 49261 Frequency prescribed by RMCMA Weekly Plant inspection Date Operator name and sign XYZ Date Operator name and sign XYZ Observation of operator, if any

Cementitious materials Aggregate stockpile

Visual Inspection for weather-tightness and leaks Visual Inspection for segregation and contamination

Weekly

Oct 22

Oct 29

okay

-

Daily

Oct 22

ABC

Oct 22

ABC

Slight contamination of 20 and 10 mm sizes due to over supply; rectifications carried out okay okay No appreciable built up for all 6 vehicles in use -

Conveyor belts and rollers Central mixer Trucks

Visual Inspection for wear and alignment Visual Inspection of blades and built up Visual Inspection of blades and built up

Weekly Weekly Weekly

Weekly Daily Weekly

Oct 22 Oct 22 Oct 22

XYZ XYZ XYZ

Oct 29 Oct 23 Oct 29

XYZ XYZ XYZ

Scale calibration for all weighing and measuring equipment

1.Mechanical/knife edge systems 2.Electrical/ load cell systems Calibration Calibration Oil change

2 monthly

Monthly

-

-

-

-

3 monthly Monthly Monthly Quarterly

Monthly Monthly Monthly Quarterly

Oct 22 Oct 22 Oct 22 Oct 22

ABC ABC ABC XYZ

Nov22 Nov22 Nov22 Jan 22

ABC ABC ABC XYZ

okay okay okay okay

Water meters Admixture dispensers Gear boxes and oil baths

- 55 -

S-4.2 Concrete Mix Design Table S-4.2: Concrete mix design information

Name of RMC Producer: X Y Z Name of Client/Contractor: A B C Site: IJKL, Mumbai Mix code Characteristic strength, N/mm2 Minimum cement content, kg/m3 (if specified) Mineral additives, kg/m3 · · · · Pulverized fuel ash Slag Silica fume Others (mention type) PPC 20 0.46 120 100 32 severe PPC 20 0.37 140 100 32 severe 100 OPC- 53 20 0.40 140 100 32 severe 50 40 OPC- 53 20 0.30 140 120 30 severe XXX 25 365 YYY 30 430 ZZZ 40 450 AAA 60 450

Cement type and grade Nominal maximum aggregate size, mm Maximum free water-binder ratio Target workability at plant, (Slump, mm) Target workability at site, (Slump, mm) Maximum temperature of concrete at the time of placing Class of sulphate resistance ( if applicable) Exposure condition ( if applicable) Class of finish ( if applicable) Mix application Method of placing Any other requirements Laboratory compressive strength of concrete, MPa 5-day 7-day 28-day Quantity, m

3

Pumping Nil

Pumping Nil

Pumping Nil

Pumping Nil

20.30 30.0 -

23.75 35.00 -

34.30 37.70 50.70 -

52.50 66.70 -

Source: Format of Table adapted from IS 49261

- 56 -

S-5 P Properties of Fresh Co o oncrete

S-5.1 Workabilit of concre 1 ty ete

Fig S-5.1.1 Typical variation in th slump of M and M40 m he M30 mixes (specified value: 100 mm)

Fig S-5.1.2 Typical variation in slump of M25 mix (specified slump: 50 m d mm)

S-5.2 Density of concrete 2 f

Fig S- Typical va -5.2 ariation in cub density of M be M25, M30 and M40 concret mixes d te

- 57 -

S-6 P Properties of Hardene Concrete o ed e

S-6.1 Strength of concrete 1 o

Fig S-6.1.1 Typical variation of 7 l 7-day and 28-day strengths of M30 concr using OPC fly ash rete C+

-6.1.2 Typical variation of 7 7-day and 28-d strengths of M40 concre using OPC fly ash day ete C+ Fig S-

S-6.2 Standard deviation 2 d Table S-6.2.Month-wise stand e dard deviatio of 28-day s on strengths of M M25, M30 an M40 mixe nd es

Month h No. of results M25 Standard deviation, MPA June 07 7 July 07 7 Aug. 07 34 34 31 4.66 4.47 4.65 32 39 35 No. of resu ults M30 Stand dard deviat tion, MP PA 4.88 4.16 3.9 95 46 32 33 of No. o results M40 Standard S deviation, d MPA 3.95 4.00 3.83 Plant standard deviation 4.47 4.15 4.25

- 58 -

June

July

August

Standard deviation, MPa

5 4 3 2 M25 M30 M40 Plant Grade of concrete

Fig S-6.2. Month-wise variation of standard deviation of 28-day strengths of M25, M30 and M40 mixes (graphical representation of Table S-6.2)

S-6.3 Acceptance criteria for compressive strength

28-day strength Av. of con. 4 fck-3 fck+3

50 Comp. strength, MPa 40 30 20 10 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 No of samples

Fig S-6.3.1 Variation of 28-day strength of concrete along with the variation in the mean of 4 non-overlapping consecutive test results for M30 concrete

- 59 -

28-day strength

60 Comp. strength, MPa 50 40 30 20 1 3 5 7 9

Av. of con. 4

fck-3

fck+3

11

13

15

17

19

21

23

25

27

29

No of samples

Fig S-6.3.2 Variation of 28-day strength of concrete along with the variation in the mean of 4 non-overlapping consecutive test results for M40 concrete

- 60 -

7. Key Personnel

Table S-7.1: Names, designation and experience of key plant personnel

Sr. no. 1 Name of personnel ABC Designation Plant-in-charge Educational qualification BE(Civil), Dip. in Business management Dip. in Civil Engg. Experience -3 years in RMC field - 2 years in construction - 7 years in RMC field Training - Distinction in CGLI Part II examination in 2007 - In-house training in management 2006 -Credit in CGLI Part-I examination - In-house training in safety and maintenance in 2007 - NCB training in concrete technology in 2005 - In-house training in QA-QC - Certificate course from recognized institution - In-house training

2

XYZ

Production-incharge

3

MNR

QC In-charge

BE (Civil)

2 years in RMC field 3 years in customer service 1 year site engineer 5 years of lab experience

4

VBS

Supervisor

B Sc

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Bureau of Indian Standards referred in Guidelines

1. 2. 3. 4. 5.

IS 4926: 2003, Ready-Mixed Concrete- Code of Practice (Second Revision), p. 18. IS 456 : 2000, Plain and Reinforced Concrete- Code of Practice ( Third Revision) ( Reaffirmed 2005), p. 100. IS 8112:1989, Specification for 43 grade Portland cement (First Revision), (Reaffirmed 2005), p. 7. IS 12269 : 1987, Specification for 53 grade ordinary Portland cement, ( Reaffirmed 2004), p.11. IS 1489 : Part : 1991, Specification for Portland pozzolana cement, Part 1, Fly-ash based (Third Revision) (reaffirmed 2005), p. 7.

6. 7. 8. 9.

IS 455 : 1989, Specification for Portland slag cement (Fourth Revision) ( Reaffirmed 2005 ), p. 7. IS 3812 : Part 2 : 2003, Pulverised Fuel Ash-Specification, Part 2 : For Use as a Admixture in Cement Mortar and Concrete, ( Second Revision ) p. 7. IS 15388 : 2003, Silica Fume- Specification, p.7. IS 12089 : 1987, Specification for Granulated Slag for Manufacture of Portland Slag Cement, , (reaffirmed 2004), p.9.

10. IS 9103: 1999, Concrete Admixtures: Specifications (First revision), (Reaffirmed 2004), p.14. 11. IS 383 : 1970, Specification for Coarse and Fine Aggregates from Natural Sources for Concrete, (Second Revision), ( Reaffirmed 2007), p. 19. 12. IS 1199 : 1959, Methods of Sampling and Analysis of Concrete, (Reaffirmed 2004), p.44. 13. IS 516: 1959, Method of Test for Strength of Concrete, (Reaffirmed 2004), p. 24.

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