Table Of ContentARCHITECTURAL
INSITU
CONCRETE
1 1
David Bennett
ARCHITECTURAL
INSITU
CONCRETE
David Bennett
Acknowledgements
Thanks for all your help and guidance.
Individuals
Bill Price, Lafarge Cement; John Taylor, Castle Cement; John Anderson
and Derek Ballard, Hanson Premix; Peter Stewart, UPM-Kymmene Wood
(WISA); Paul Raybone and Derek Smith, A Plant Acrow; Dennis Higgins,
Civil and Marine (GGBS); Lindon Sear, UKQAA (PFA); Edwin Trout, Concrete
Information Service; Peter Jackson, PT Group Ltd; Dr Adrian Brough, Leeds
University; Clara Willet, English Heritage.
Companies
Lanxess GmbH – Bayferrox Pigments; Kronoply GmbH; PERI Ltd UK;
SGB Ltd; Creteco Ltd; Trent Concrete Ltd; Wacker (UK) Ltd; Castle Cement.
© David Bennett, 2007
Published by RIBA Publishing, 15 Bonhill Street, London EC2P 2EA
ISBN 978 1 85946 259 1
Stock Code 61854
The right of David Bennett to be identifi ed as the Author of this work has been
asserted in accordance with the Copyright, Designs and Patents Act 1988.
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 prior permission
of the copyright owner.
British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library.
Publisher: Steven Cross
Project Editor: Alasdair Deas
Editor: Andrea Platts
Designed by Paul Gibbs, Kneath Associates
Printed and bound by Cambridge University Press
While every effort has been made to check the accuracy of the information
given in thisbook, readers should always make their own checks. Neither the
Author nor the Publisher accepts any responsibility for misstatements made in
it or misunderstandings arising from it.
RIBA Publishing is part of RIBA Enterprises Ltd
www.ribaenterprises.com
CONTENTS
Introduction
Part One: Technology
Materials and mixes 002
Formwork and practice 041
Concrete workmanship 060
Part Two: Case Studies in Concrete
Thames Barrier Park Patel Taylor 075
Persistence Works Feilden Clegg Bradley 084
The Art House Fraser Brown Mackenna 097
The Anderson House Jamie Fobert 107
Aberdeen Lane Azman Owens 117
One Centaur Street deRMM 127
85 Southwark Street Allies and Morrison 137
The Bannerman Centre Rivington Street Studio 147
The Brick House Caruso St John 157
The Collection Panter Hudspith 167
Playgolf, Northwick Park Charles Mador 179
E-Innovation Centre BDP Manchester 189
The Jones House Alan Jones 199
Spedant Works Greenway and Lee 209
Central Venture Park Eger Architects 219
Glossary of concrete terminology 228
Further reading 230
Useful contacts 230
Picture credits 230
Index 231
INTRODUCTION
Concrete as an architectural and structural material has gone
through many changes and evolutions in its development over
the years, but probably none more dramatic than in the past
decade. There is renewed interest in concrete’s plastic and
aesthetic qualities in architecture today, helped and encouraged
by the expressive way that British architects have exploited
its self-fi nished quality and form with great success. It clearly
demonstrates that standard truck-mixed concrete and the right
selection of formwork and placement techniques can produce
award-winning architecture at affordable prices. What is
also a revelation is that many of the architects whose work is
highlighted in the case studies in the second part of this book
have never designed exposed concrete on such a scale before.
What they discovered is that there is a wealth of knowledge
within the concrete industry that can be accessed to give them
the confi dence and encouragement to realise their ambitions.
The fi rst part of this book provides suffi cient in-depth technical
guidance and practical information on the mechanics and
fundamentals of how to achieve a fi ne concrete fi nish that there
should be no need to make a frantic search through countless
books or websites to fi nd solutions.
ARCHITECTURAL INSITU CONCRETE
1 2
The techniques of concrete compaction were once thought to be feasible only Infused with such optimism, there
and placement, the surface treatment with precast concrete. The added value is a driving need to take stock and
of cast concrete to prevent dirt ingress is that it can be built as a monolithic consider climate change, how we can
and staining, detailing of panel layouts, load-carrying structure with built-in reduce CO emissions and sustain
2
concrete workmanship and general tips thermal mass. New materials, new forms our natural world through responsible
on good practice are well documented and new developments, like the use design and considerate architecture.
and comprehensively covered. But of fabric formwork, ultra high strength What can concrete do to help? This
perhaps the two most important aspects concrete, recycled waste and steel book is not going to provide those
are the control of colour in specifying a fi bre reinforced concrete, will continue solutions, but the examples will certainly
truck-mixed concrete and the selection to keep concrete forever inventive and make suggestions and show what has
of the form face which imparts the
responsive to change. been done, and the reading list in the
character and defi nition of the surface
reference section highlights excellent
appearance. Considerable commentary Whether you prefer the smooth,
publications on the subject. We can all
has been developed on how concrete unmarked surface of fi lm faced ply,
make a contribution by reducing site
is produced, what controls its colour the subtle fl ecks of untreated birch,
wastage, by recycling building materials
and the properties and performance of the heavy graininess of sawn timber,
– especially formwork, by using public
formwork materials commonly available, the marble softness of polythene-lined
transport instead of driving a car and
backed up with good illustrations to give plywood, there is so much variety, choice
utilising thermal mass to reduce energy
the designer insight and understanding and opportunity to experiment that there
consumption. It is equally important to
for their selection and specifi cation. is something here to suit everyone’s
design concrete buildings with durable
taste and predilections. The more you
The case studies which make up the fi ne fi nishes that will last a lifetime,
discover, the more you want to innovate.
second part of the book manifest the that will not dilapidate or decay or need
The more deeply ingrained your depth
integrity and quality of insitu concrete rebuilding in the near future – another
of understanding and mastery of the
in its many diverse forms, exploiting the argument for the sustainability of
material, the more you realise how little
grey coolness of concrete, its planar concrete.
we really know of liquid rock’s potential.
smoothness and textured tonality. I make
And yet, on refl ection, judging by the There are many people I wish to thank
no apology for mentioning The Collection
(aka the Lincoln and City County 15 schemes highlighted in the case for helping me put this book together.
Museum) designed by architects Panter studies, there is a dynamism that echoes If your name does not appear the
Hudspith, which represents a signifi cant the pioneering spirit of the 1930s acknowledgments, it’s not because you
step forward in the advancement of Modern Movement and something of the have been ignored, it’s because I’m
self-compacting concrete. The quality concrete fi nesse of Swiss architecture forgetful and have been remiss. Thanks
of the board-marked surface in the café in what has been achieved. In these to all those wonderful people – the
area is as good as the pictures of the projects we can see an increasing architects, the clients, the engineers,
walls and as perfect as porcelain. Here number of architects returning to contractors, the cement manufacturers,
is a poured-in-place material that can concrete to presage the dawn of a new the concrete andformwork material
produce fi nishes and formed shapes that era of concrete realism. suppliers – those champions of concrete
fi g 1-2
River City Plaza, Chicago
3 4
– for giving of their time so generously fi rst book on architectural concrete in
and for allowing the publisher to use the 1998, the images of the Social Science
images of the buildings, production plant Faculty Centre (1999) in Oxford were
and materials illustrated in the book. taken, at a stage when the internal
Thanks to Ian Cox and The Concrete areas were incomplete and there was
Centre for generously supporting this the odd scaffold tube and scaffold
publication, to Steven Cross and the board in the picture. It is a gem of a
publishing team at RIBA Enterprises building by Foster and Partners and a
for making it happen and to Kneath totally exposed concrete structure with
Associates and the book design team for fi ne detailing and well-crafted concrete
the fantastic visual layouts. workmanship. The internal shots of the
fi nished interior, without scaffold tubes
Just when you think you know your
this time, are yet another reminder that a
subject, you come across a building that
good designer and competent concrete
takes your breath away and brings you
contractor can work wonders with
to your knees in admiration. One such
concrete – it’s not that diffi cult. If I had
is River City Plaza (1985) in Chicago,
to pick one building that is outstanding
completed some 20 years ago and
for sheer bravado, audacity, architectural
still looking great. It is a building from
verve, construction innovation and
which some of the notes on architectural
engineering simplicity (not easy to
concrete compaction were derived
do) then it would be the extraordinary
thanks to Symonds Corporation, the
red-pigmented, gunited, surface skin
formwork specialists who helped build it.
and structure of the Minnaert Building
It ranks among the fi nest cast-in-place
in Utrecht University. The architect is
concrete structures I have seen and was
Nuetlings Riedijke and the structural
the last building that Bertrand Goldberg
engineers ABT in Amsterdam. But
designed. It has curved board-marked
that was before this book was written
load-bearing walls using formliners
and there are now 15 new projects to
glued to curved metal formwork and
consider … what a lovely dilemma! I
was developed for a social housing
hope you fi nd the technical information
programme.
rewarding and the concrete case studies
Two other buildings deserve special an inspiration for your future ambitions.
mention and were important in my
early understanding of architectural David Bennett
insitu concrete and just how creative July 2007
architects can be when they master their
art. When researching material for my
5
fi g 3-4 fi g 5
Social Science Faculty, Oxford Minnaert Building, Utrecht University
PART1
TECHNOLOGY
Materials and mixes
Cement 002
Aggregates 014
Concrete production 022
Concrete colour 034
The right mix 039
Formwork and practice
Introduction 041
Untreated timber 042
Film faced plywood 044
Oriented strand board 046
Chipboard (for single usage) 047
Metal 048
Others 048
Formwork practice 050
Concrete workmanship
Introduction 060
Handling and placing 060
Compaction and consolidation 062
Reinforcement and cover 064
Curing 067
Trial panels 067
Clean, dirt-free surface 067
Stains and blemishes 068
Remedies 070
Repairs 070
1
MATERIALS AND MIXES
1
CEMENT
AN INTRODUCTION
Limestone and chalk are composed Dry process
of the fossilised remains of millions of
In the dry process, the raw materials
With Bill Price, micro- organisms that lived in the sea. are introduced without additional
Lafarge Cement UK It is an interesting quirk of prehistory water. These natural ingredients
that the shells of the marine creatures are fi nely ground and blended
Concrete is the most widely used
of the carboniferous or cretaceous eras (homogenised) in the optimum
construction material on earth and,
are now being recycled to provide us proportions. The raw materials can
at its simplest, cement is the glue, or
with concrete. be preheated in a fl ow of hot kiln
binder, that holds concrete together.
exhaust gases prior to entering the
Consequently, cement makes a There are a number of different
cement kiln itself. This preheating
vitally important contribution to the processes used commercially to
dries the materials, and in the
appearance of the world we live in. produce cement, the most common
similar but more effi cient process
But what is ‘cement’? of which are: known as ‘precalcining’ it also
While there are a number of different decarbonates the majority of the
types of cement, the most common is > the dry process calcium carbonate in the limestone
‘Portland’ cement. This was named > the semi-dry process or chalk. The dry materials are
by its inventor, Joseph Aspdin, after then heated in a rotating kiln to a
its supposed resemblance to Portland > the semi-wet process and temperature of around 1,500 °C. At
stone when set. This type of cement > the wet process. this temperature, the homogenised
has been produced for over 150 years raw materials are only partially
and is available worldwide. The energy consumption and melted, although there is a complete
the energy effi ciency of cement transformation of the mineral
In terms of its basic chemistry,
assemblage. The partial melting
production vary between the
Portland cement can be represented combined with the rotation of the
different processes (see Table 1).
in terms of four main oxides, which kiln produces a granular material
The dry process, particularly when
make up more than 95 per cent known as cement clinker. The raw
combined with precalcining, is the
of its composition. These are CaO materials remain in the kiln for
most energy-effi cient process
(lime), SiO2 (silica), Al2O3 (alumina) about half an hour in a precalcined,
and Fe O (iron oxide). The dry process system.
2 3
remainder consists of various minor
Table 1
constituents, including magnesium, Semi-dry process
Relative energy performance
sulphur and alkalis. of different cement production In the semi-dry process, the raw
processes materials are initially prepared in
HOW IS IT MADE?
the same way as for the dry process,
The manufacture of Portland cement but then pelletised (sometimes
Process Relative energy
is a closely controlled process akin termed ‘nodulised’) into spheres of
consumption
to large-scale chemical engineering. around 15 mm diameter with about
for 1 t of clinker
The necessary raw materials are 12 per cent moisture. The pellets are
principally a source of calcareous gently preheated on a moving grate
material, typically limestone or Dry + precalciner 1.00 preheater before entering the kiln.
chalk, which makes up about 80 per Dry + preheater 1.09
cent of the raw ingredients, a source Semi-wet process
Semi-dry 1.14
of silica – either clay or shale – and The semi-wet process involves
Semi-wet 1.21
a pinch of sand and iron oxide to combining the ground raw materials
optimise the chemistry. Wet 1.95 with around 20 per cent moisture into
fi g 1
Padeswood cement works
2
