Fundamental Research on Creep and Shrinkage of Concrete

514 Pages·1982·30.103 MB·English

by  Max J. Setzer (auth.), F. H. Wittman (eds.)

FUNDAMENTAL RESEARCH ON CREEP AND SHRINKAGE OF
CONCRETE
FUNDAMENTAL
RESEARCH ON CREEP
AND SHRINKAGE OF
CONCRETE
Edited by
F. H. WITTMANN
•
1982
MARTINUS NIJHOFF PUBLISHERS
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Library of Congrf'ss Cataloging in Publication Data
Main entry under title:
Fundamental research on creep and shrinkage of
concrete.
Papers presented at a conference held at the
Swiss Federal Institute of Technology in Lausanne
in Sept. 1980.
Includes index.
1. Concrete--Creep--Congresses. 2. Concrete-
Expansion and contraction--Congresses. I. Wittmann,
F. H. (Folker H.)
TA440.F86 620.1'3633 81-18990
AACR2
ISBN-J3: 978-94-010-37/8-1 e-ISBN-J3: 978-94-010-3716-7
DOl: 10.1007/978-94-010-37/6-7
Copyright © 1982 by Martinus Nijhoff Publishers, The Hague.
Softcover reprint oft he hardcover 1st edition 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, mechanical, photocopying, recording, or otherwise,
without prior written permission of the publishers,
Martinus Nijhoff Publishers, P.O. Box 566,2501 CN The Hague, The Netherlands.
v
PREFACE
Today research on creep and shrinkage of concrete is diversified
to such a degree that specialists working in different areas
sometimes find it difficult to understand one-another. Materials
scientists are mainly interested in processes on a microstructural
level but they do not necessarily understand the relevance of time
dependent deformation in structural design. On the other hand
engineers who apply simplified model laws in non-elastic structural
analysis are not always in the position to judge the limitations
implied in their approach. It is generally realized that further
development can be stimulated by a more effective exchange of
results and ideas among the different groups involved.
In an attempt to bridge this obvious gap in September 1980 there
was a Conference organized at Swiss Federal Institute of Technology
in Lausanne. The papers presented at this meeting covered the wide
range starting with microstructural aspects and mechanisms and
including constitutive modelling and structural creep analysis.
These contributions together with summaries of two panel discussions
are being published in this volume.
All serious of the meeting have been introduced by invited lectures.
These papers will be published in a special volume "Creep and
Moisture Effects in Concrete". This special volume is rather to be
a general survey of the different areas covered while the present
conference proceedings provide a unique selection of research
papers.
Nowadays time-dependent deformation of concrete can be taken into
consideration realistically by computerized structural analysis.
So far, however, we do not have appropriate model laws to describe
the complex materials behaviour. But several interesting and pro
mising approaches exist in this new branch of materials science
which is generally called concrete mechanics. It is hoped that this
compilation of papers will help to clarify the common aim and
stimulate further research work.
It is a pleasure for me to thank all my collaborators at the
Laboratory for Building Materials Science at Swiss Federal Institute
of Technology. Without their continuous help during the organization
of the meeting and the preparation of the conference proceedings it
would have been impossible to achieve the goal. At the same time
I would like to thank Mr. Schrijver from Sijthoff and Noordhoff for
the efficient collaboration during the editing process.
Lausanne, May 1981 F.R. Wittmann
VII
TABLE OF CONTENTS
I. MECHANISMS OF CREEP AND SHRINKAGE 1
Pr>eface v
M.J. SETZER
A model of hardened cement paste for linking shrinkage and
creep phenomena
R.L. DAY and B.R. GAMBLE 15
The use of activation spectrum theory to describe creep in
concrete
J. LUIJERINK 27
Deformation kinetics of concrete
L.J. PARROTT and J.F. YOUNG 35
Shrinkage and swelling of two hydrated alite pastes
A.K. MULLICK 49
Creep and microstructural changes in concrete
S. SABRI and J.M. ILLSTON 63
Isothermal drying shrinkage and wetting swelling of
hardened cement paste
II. STOCHASTIC NATURE OF CREEP AND SHRINKAGE 73
F. ALOU and F.H. WITTMANN 75
Etude experimentale de la variabilite du retrait du beton/
Experimental study of the variability of shrinkage in con
crete
H.W. REINHARDT, M.G.M. PAT and F.H. WITTMANN 93
Variability of creep and shrinkage of concrete
H.A.W. CORNELISSEN 109
Creep of concrete - A stochastic quantity
III. EXPERIMENTAL TECHNIQUES AND RESULTS 125
F. KRUML 127
A contribution to the problem of reversible and irreversible
creep of compact structural concretes
M. MAMILLAN 135
Checking the principZe of superposition by testing
VIII
P. ACKER 149
Drying of concrete: Consequences for the evaluation of
creeptest
H. TROST 171
Relaxation tests on very oZd concrete
R. WALTHER and T. PARETH 179
Rheological properties at high temperature of a concrete with
a crushed limestone aggregate and blast furnace cement
U. SCHNEIDER 193
Creep effects under transient temperature conditions
K. ALTMANN 203
Shrinkage of concrete in e$treme climate
D.W. HOBBS 213
Drying shrinkage of symmetrically reinforced concrete and
some estimates of the creep of concrete in tension
M. KAVYRCHINE and Z.T. NUNG 227
Deformations de sections transversales et de poutres flechies
so us chaPge soutenue
L. BRULL and K. KOMLOS 239
Early shrinkage of hardening cement pastes
IV. CONSTITUTIVE RELATIONS FOR CREEP AND SHRINKAGE 249
G.,f. CREUS 251
Non linear constitutive equations for concrete
,f.E. ,fONASSON 259
Analyses of shrinkage in concrete
H.S. MULLER and H.K. HILSDORF 269
Comparison of prediction methods for creep coefficients of
structural concrete with experimental data
L.F. NIELSEN 279
On the prediction of creep functions for concrete
V. OBSERVATIONS ON STRUCTURES 291
H.G. RUSSEL and K.N. SHIU 293
creep and shrinkage behaviour of tall buildings and long
span bridges
C.H. THORNTON and I.P. LEW 305
Analysis of restrained concrete structures for creep and
shrinkage
T. ,fANOV 323
Experimental Analysis of prestressed concrete bridges
IX
VI. STRUCTURAL CREEP ANALYSIS 339
R. IDING and B. BRESLER 341
Prediction of shrinkage stresses and deformations in concrete
P. E. ROELFSTRA 353
Computerized structural analysis applied to large span
bridges
W. HAAS 369
Numerical analysis of creep and shrinkage on concrete
structures
Y. BANGASH and G.L. ENGLAND 381
The influence of thermal creep on the operational behaviour
of complex structures
S. MERAZZI, P. STEHLIN and F.A. BROGAN 405
Viscoelastic stability analysis of shells
V. LAZIC and J. LAZIC 413
Stresses and displacements of composite and prestressed
structures
V. KRISTEK and Z. SMERDA 425
Simplified calculation of the relaxation of stress respecting
the delayed elasticity
D.W. HOBBS 439
Shrinkage and load induced curvature of reinforced concrete
beams
M. KOPRNA 451
Prise en compte du fluage par la methode des forces
R.J. SUTER 459
a
Comportement d'une structure continue realisee l'aide
d'elements prefabriques
J.P. JACCOUD 471
Deformation des dalles en beton: Methode bilineaire pour le
calcul des fleches
M.A. CHIORINO and F. MOLA 485
Analysis of linear visco-elastic structures subjected to
delayed restraints
F. MOLA and G. CREAZZA 497
General and approximate method for the analysis of linear
visco-elastic structures sensitive to second order effects
Panel Discussion I
MICROSTRUCTURAL ASPECTS, MECHANISMS AND CONSTITUTIVE MODELING 511
Chairman: F. H. Wittmann
Recorder: L.J. Parrott
Panelists: Z.P. Bazant, C.D. Pomeroy, E. Cinlar, J.W. Dougill,
H.K. Hilsdorf, S.E. Pihlajavaara and J.F. Young
x
PaneZ Disaussion II
CONSTITUTIVE MODELING AND STRUCTURAL CREEP ANALYSIS 515
Chairman: Z.P. Bazant
ReaordBr: D.W. Hobbs
PaneZists: C.A. Anderson, T. Javor, M.A. Chiorino, R. Favre,
B.L. Meyers, H. Trost, and K. WiZZam
Part I
Mechanisms of Creep and Shrinkage
3
A MODEL OF HARDENED CEMENT PASTE FOR
LINKING SHRINKAGE AND CREEP PHENmmNA
Max J. Setzer
Technische Universitat MUnchen,
Abteilung fUr Werkstoffphysik
Baumbachstr. 7,D-8000 MUnchen 60
ABSTRACT:
It is shown that swelling of hardened cement paste is
influenced by two different mechanisms:
1) In the lower vapour pressure region (r.h.< 38%) a
reduction of the surface energy of the gel particles
leads to an expansion of the single particles.
2) In the upper vapour pressure region the whole
structure is widened by a change of interparticle
attraction in the small gel pores. (disjoining pressure)
Both effects can clearly be distinguished. The creep
velocity of specimens stored at constant but different
humidities increases at values above 40% r.h. This in
crease can be correlated to that part of the swelling
which results from the expansion of the structure of
hcp. A theoretical explanation is made through adapt
ing the "Extended Munich Model" and using the "thermo
dynamic approach".
Zusammenfassung:
Es wird gezeigt, daB das Quellen von Zementstein von
zwei verschiedenen Mechanismen beeinfluBt wird:
1) 1m unteren Feuchtebereich (r.h.< 38%) sinkt die
freie Oberflachenenergie der Gelpartikel abo Dies
fUhrt zu einer Expansion der einzelnen Partikel.
2) 1m oberen Feuchtebereich wird die gesamte Struktur
aufgeweitet durch eine Anderung der Anziehung der Teil
chen untereinander. (disjoining pressure oder Spalt
druck)
Beide Effekte konnen gut getrennt werden. Die Kriech-