Precast concrete materials, manufacture, properties and usage - Chapter 0 pot

PRECAST CONCRETE

Materials, Manufacture, Properties and Usage

Copyright Applied Science Publishers Ltd 1982
PRECAST CONCRETE

Materials, Manufacture,
Properties and Usage





M.LEVITT
ARCS, BSc, DIC, PhD
Head—Materials Science Department,
John Laing Research and Development Limited,
Borehamwood, Hertfordshire, UK





APPLIED SCIENCE PUBLISHERS
LONDON and NEW JERSEY
Copyright Applied Science Publishers Ltd 1982
This edition published in the Taylor & Francis e-Library, 2004.
APPLIED SCIENCE PUBLISHERS LTD
Ripple Road, Barking, Essex, England

APPLIED SCIENCE PUBLISHERS, INC
Englewood, New Jersey 07631, USA

British Library Cataloguing in Publication Data
Levitt, M.
Precast concrete.
1. Precast concrete
I. Title
691′·3 TA683·7
ISBN 0-203-49057-6 Master e-book ISBN


ISBN 0-203-79881-3 (Adobe eReader Format)
ISBN 0-85334-994-0 (Print Edition)

WITH 40 TABLES AND 109 ILLUSTRATIONS

© APPLIED SCIENCE PUBLISHERS LTD 1982
All rights reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted in any
form or by any means, electronic, mechanical, photocopying,
recording, or otherwise, without the prior written permission of
the publishers, Applied Science Publishers Ltd, Ripple Road,
Barking, Essex, England
Copyright Applied Science Publishers Ltd 1982
ACKNOWLEDGEMENTS

The author wishes to express his appreciation to John Laing Research
and Development and The British Precast Concrete Federation Limited
for their permission to publish this book. In particular the

encouragement of Laing should be mentioned, with particular reference
to assistance given by Cyril Hobbs, the Laing Group’s Scientific Adviser,
as well as the Precast Concrete Federation’s declassification of a great
deal of the originally restricted research data.
Gratitude is also expressed to the following precast concrete
manufacturers who not only supplied illustrations, but many of whom
also took upon themselves the task of checking the technical accuracy of
many parts of the original manuscript.
Bardon Hill Quarries Limited
Beton Machinery Sales Limited
Dean Jesmond & Co.
ECC Quarries Limited
Forticrete Limited
Richard Lees Limited
Marshalls of Halifax
Redland Tiles Limited
Rocla Pipes Limited
Thermalite Limited

Copyright Applied Science Publishers Ltd 1982
INTRODUCTION

This book is intended to meet the need for a general treatise on precast
concrete, as the last relevant book on this subject was published in 1961.
Since then there have been several publications dealing with particular
parts of the subject which serve as useful back-up reading, but the precast
concrete industry is complex and needs to be discussed in both general
and particular terms over a large number of subject areas.
The book is aimed not only at people who have considerable
experience but also at those new to the subject. Both of these groups of

people will wish to extend their knowledge, either in their existing fields
or new ones. Although high degrees of knowledge of mathematics,
physics, chemistry and engineering are not required of the reader, it is
assumed that he or she will have had two or three years of what may be
loosely and internationally described as further education. Specifiers,
manufacturers, contractors and teachers will all find something of use.
Engineering design and detailing are not covered in this book but
details of materials, properties, manufacture and usage are discussed in
as full a way as possible. Most of the data, although based upon UK
experience, are equally applicable in other countries. Care has been taken
to ensure that no matter what process, environment or materials are
under consideration the reader will be able to abstract the data required
to facilitate production and use of as good a quality product as possible.
The common factors in precast concrete products are aggregates,
hydraulic cement and water, coupled with a technique for moulding these
into a required shape. Although certain rules and guidelines can be laid
down, technology can only be used part of the way, as ‘know-how’ and
a large degree of ‘alchemy’ play important roles. One of the purposes of
this book is to outline how far one can take the technology and when one
needs to develop one’s own experience. All that is asked of the reader is
the same number of degrees of flexibility as there are variables relating to
Copyright Applied Science Publishers Ltd 1982
the properties of the final product. A rigid philosophy will not bear fruit,
therefore, great care should be exercised to take a number in its context
and not treat it as sacrosanct.
The reader should also bear in mind that imparting good practice
information rarely breaches secrecy and will always result in a better image
for the industry as a whole. Bad performance, whether due to design,
materials and/or workmanship, is news that travels fast and even the
innocent suffer in the aftermath. Since precast concrete is often one of the

choices open to the specifier no one can be excused for promoting the
alternatives through their own errors. Pride in the product is the aim and
this is easy to achieve. Should any of the basic rules or guidelines be ignored
one will find that there is only one rule and that is that the percentage
number of rejects is inversely proportional to the control one has.
BIBLIOGRAPHY
H.G.CHILDE, Concrete Products and Cast Stone, Concrete Publications,
London, Ninth Edition, 1961.
Architectural Precast Concrete, Prestressed Concrete Institute, Chicago, 1973.
J.G.RICHARDSON, Formwork Construction and Practice, Cement and
Concrete Association, London, 1977.

Copyright Applied Science Publishers Ltd 1982
CONTENTS

Acknowledgements
Introduction
1. Moulds and Materials
2. Admixtures
3. Pigments
4. Fly Ash
5. Production—General Considerations
6. Production—Specific Processes
7. Accelerated Curing
8. Properties and Performance
9. Quality Assurance
10. Repairs
Copyright Applied Science Publishers Ltd 1982