time-dependent behaviour of concrete-filled steel tubular arch bridges

241 Pages·2017·10.61 MB·English

TIME-DEPENDENT BEHAVIOUR OF
COMPOSITE STEEL-CONCRETE SLABS
PREPARED WITH RECYCLED COARSE
AGGREGATE
By
QINGHE WANG

B.Sc. (Civil Engineering), Harbin Institute of Technology – Harbin, China
M.Sc. (Structural Engineering), Harbin Institute of Technology –Harbin, China
A thesis submitted in fulfilment
of the requirements for the degree of Doctor of Philosophy
School of Civil Engineering
The University of Sydney
Australia

April 2017
The University of Sydney
CERTIFICATE OF ORIGINALITY
I certify that the work in this thesis has not previously been submitted for a degree nor
has it been submitted as part of requirements for a degree except as fully acknowledged
within the text.
I also certify that the thesis has been written by me. Any help that I have received in my
research work and the preparation of the thesis itself has been acknowledged. In addition,
I certify that all information sources and literature used are indicated in the thesis.

QINGHE WANG

-ii-
Abstract
ABSTRACT
The purpose of this research is to investigate the influence of recycled coarse aggregate
(RCA) on the long-term behaviour of composite steel-concrete slabs. Several types of
tests were conducted to fulfil the research, including material tests on recycled concrete
(RAC), non-uniform shrinkage tests on small-scale slabs, and long-term tests on
full-scale slabs. The systematic investigation on the long-term behaviour of composite
slabs provided valuable experimental data, based on which design procedures were
proposed for their routine design.
In the materials tests, the influence of service time of RCA and mixing methods on the
mechanical properties of RAC were first investigated, i.e. compressive strength, static
modulus of elasticity, and shrinkage deformations. Based on the experimental data
collected as part of this study, the model to predict the RAC elastic modulus was
developed accounting for the influence of residual mortar content (C ), and the model
RM
to estimate the RAC compressive strength development over time was modified based on
EC2 model to account for the ―internal curing effects‖. The test results also indicated that
the parent concrete quality influenced the shrinkage behaviour of resulting concrete. In
this case, the autogenous and drying shrinkage tests were conducted on RAC using RCA
obtained from parent concrete having different service time and compressive strengths.
The models to predict the autogenous and drying shrinkage behaviour of RAC were
developed accounting for the combined effects of parent concrete quality and residual
mortar content (C ).
RM
In the shrinkage tests on the small-scale slabs, the relative humidity (RH) and strain
distributions through the thickness of 17 slabs were monitored over time to investigate
the influence of RCA on the non-uniform shrinkage profile of composite slabs. Test
parameters consisted of RCA replacement ratios, slab depths and sealing conditions of
the slab surfaces. The mechanism of non-uniform shrinkage in composite slabs was
revealed by the measured RH distributions through the thickness of slabs. The
experimental strain results were used to further validate a numerical model capable of
-iii-
The University of Sydney
incorporating the effects of non-uniform shrinkage inside composite slabs, based on
which the influence of RCA on the long-term composite slab curvatures was investigated
and the importance of considering the non-uniform shrinkage in the long-term curvatures
of RAC composite slabs was highlighted.
In the long-term tests on the full-scale slabs, seven slabs were prepared and measured,
including three steel-bars truss slabs and four composite slabs. The test was designed to
evaluate the influence of RCA on the time-dependent behaviour of composite
steel-concrete slabs and to separate the effects of creep and non-uniform shrinkage. A
nonlinear finite element model was developed to account for the time-dependent
behaviour of composite slabs to include the effects of non-uniform shrinkage, creep and
concrete cracking, and validated against the test results reported in this thesis. A
parametric study was then carried out to evaluate the influence of time effects on the
long-term deflections of composite steel-concrete slabs prepared with RCA. Based on the
experimental investigations and numerical simulations, a design approach to be used for
routine design of RAC composite slabs was proposed and validated.
Keywords: recycled coarse aggregate; recycled aggregate concrete; composite slabs;
non-uniform shrinkage; elastic modulus.
-iv-
Preface
PREFACE
This thesis is submitted in fulfilment of the requirements for the degree of Doctor of
Philosophy at the School of Civil Engineering, The University of Sydney, Australia.
Some of the work described in this thesis has been supported by papers that have
been accepted in or submitted to journals, or presented or accepted in conferences,
viz.:
[1] Qinghe Wang, Gianluca Ranzi, Yuyin Wang and Yue Geng (2016). Long-term
behaviour of simply-supported steel-bars truss slabs with recycled coarse
aggregate. Construction and Building Materials. 116: 335-346.
[2] Yuyin Wang, Qinghe Wang, Yue Geng, Gianluca Ranzi (2016). Long-term
behaviour of simply-supported composite slabs with recycled coarse aggregate.
Magazine of Concrete Research. 68(24):1278-1293.
[3] Qinghe Wang, Yuyin Wang, Yue Geng and Huan Zhang (2016). Influence of
mixing methods on the mechanical behaviours of recycled aggregate concrete.
Journal of Building Structures. 37 (Sup2):79-87. (In Chinese).
[4] Qinghe Wang, Gianluca Ranzi, Yue Geng, Yuyin Wang. (2015). Long-term
experiments of composite slabs using recycled coarse aggregate. 27th Biennial
National Conference of the Concrete Institute of Australia in conjunction with
69th RILEM Week, Sydney: Concrete Institute of Australia. 669-678.
[5] Changyong Liu, Qinghe Wang, Yuyin Wang and Degang Shen (2013). Flexural
behaviour of precast reinforced concrete beams with steel end connectors. Journal
of Building Structures. 34(Sup2):208-214. (In Chinese).
[6] Yue Geng, Qinghe Wang, Yuyin Wang and Huan Zhang (2016). Influence of
service time of parent concrete and mixing method on the mechanical properties
of concrete. Construction and Building Materials. (Under review).
[7] Qinghe Wang, Yuyin Wang, Gianluca Ranzi, Yue Geng and Huan Zhang.
Influence of parent concrete on the autogenous shrinkage behaviour of recycled
aggregate concrete (RAC). (Under preparation to be submitted).
-v-
The University of Sydney
[8] Qinghe Wang, Yuyin Wang, Gianluca Ranzi, Yue Geng and Huan Zhang.
Influence of parent concrete on the drying shrinkage behaviour of recycled
aggregate concrete (RAC). (Under preparation to be submitted).
[9] Qinghe Wang, Gianluca Ranzi, Yuyin Wang, Yue Geng and Huan Zhang. Effects
of non-uniform shrinkage on the time-dependent behaviour of composite slabs
prepared with recycled aggregate concrete. (Under preparation to be submitted).
-vi-
Acknowledgements
ACKNOWLEDGEMENTS
I would like to thank my supervisor Professor Gianluca Ranzi at The University of
Sydney for his continuous supports and encouragements for the past four years. I
will try my best to learn the way my supervisor works and the way my supervisor
corporates with his students. I feel proud as your student at present, and I hope one
day you could be proud as my supervisor.
I also greatly appreciate the help from my supervisor Professor Yuyin Wang and
co-supervisor Associate Professor Yue Geng at Harbin Institute of Technology.
Without your help and inspiration, I could not complete the Ph.D. study. I will try
hard to follow you on the dedication to research. I cannot thank more Professor Hua
Yang, Professor Lanhui Guo, Dr. Changyong Liu and Dr. Faqi Liu for your care on
my study and my life. The help from Professor Xiaojian Gao, Mr. Hongwei Deng,
Mr. Hongbo Liu is appreciated.
I also want to appreciate the follow colleagues who have worked with me in the lab
and have encouraged me when I felt down for the past four years. They are Degang
Shen, Kai Zhang, Xiaotong Wang, Huan Zhang, Chunguang Zhu and Meng Wei. I
wish our friendship will last long. The help from the colleagues Dr. Chao Hou, Mr.
Dongxin Liu, Mr. Maolin Liu, Mr. Pengyu Huang, Mr. Chongpu Zhai, Dr. Faham
Tahmasebinia, Dr. Md Mahfuzur Rahman and Dr. Ahmed Faheem at the University
of Sydney is appreciated.
Last but not the least, I am very grateful to my parents and my wife for their
supports, understanding, endless patience and encouragement throughout this entire
journey.
-vii-
The University of Sydney
TABLE OF CONTENTS

CERTIFICATE OF ORIGINALITY.............................................................................. ii
ABSTRACT................................................................................................................. iii
PREFACE ...................................................................................................................... v
ACKNOWLEDGEMENTS ......................................................................................... vii
CHAPTER 1 Introduction ............................................................................................. 1
1.1 Introduction ..................................................................................................... 1
1.2 Background ...................................................................................................... 1
1.3 Objectives of the thesis ................................................................................... 4
1.4 Outline of the thesis......................................................................................... 4
1.5 References ....................................................................................................... 7
CHAPTER 2 Literature Review .................................................................................... 9
2.1 Introduction ..................................................................................................... 9
2.2 Physical properties and structural applications of RCA ................................. 9
2.2.1 Physical properties of RCA .................................................................. 9
2.2.2 Structural applications of RCA .......................................................... 11
2.3 Literature Review .......................................................................................... 13
2.3.1 Mechanical properties of RAC ........................................................... 13
2.3.2 Non-uniform shrinkage behaviour of composite slabs ...................... 33
2.3.3 Short-term and long-term behaviour of composite slabs ................... 40
2.4 References ..................................................................................................... 50
CHAPTER 3 Influence of Service Time of RCA and Mixing Methods on the
Mechanical Properties of RAC ............................................................................ 62
3.1 Introduction ................................................................................................... 62
3.2 Experimental programme .............................................................................. 63
3.2.1 Material............................................................................................... 63
3.2.2 Concrete mixtures ............................................................................... 65
3.2.3 Mixing method ................................................................................... 66
3.2.4 Specimens casting .............................................................................. 67
3.2.5 Test methods ....................................................................................... 67
3.3 Experimental tests and results ....................................................................... 67
3.3.1 Compressive strength ......................................................................... 67
-viii-
Table of contents
3.3.2 Static modulus of elasticity ................................................................ 74
3.3.3 Shrinkage ............................................................................................ 77
3.4 Mechanical models for RAC ......................................................................... 80
3.4.1 Model to predict the compressive strength development for RAC .... 80
3.4.2 Model to predict the static modulus of elasticity for RAC ................ 82
3.4.3 Evaluation of existing shrinkage models for RAC ............................ 84
3.5 Conclusions ................................................................................................... 86
3.6 References ..................................................................................................... 88
CHAPTER 4 Influence of Parent Concrete on the Shrinkage Behaviour of Normal
Grade RAC .......................................................................................................... 91
4.1 Introduction ................................................................................................... 91
4.2 Experimental programme .............................................................................. 92
4.2.1 Material............................................................................................... 92
4.2.2 Concrete mixtures ............................................................................... 95
4.2.3 Specimens casting and curing ............................................................ 95
4.2.4 Test methods ....................................................................................... 97
4.2.5 Mechanical properties of fresh and hardened concrete ...................... 97
4.3 Experimental results ...................................................................................... 99
4.3.1 Autogenous shrinkage ........................................................................ 99
4.3.2 Drying shrinkage .............................................................................. 106
4.4 Modification of existing shrinkage models for RAC .................................. 111
4.4.1 Modified autogenous shrinkage model ............................................ 111
4.4.2 Modified drying shrinkage model .................................................... 116
4.5 Conclusions ................................................................................................. 123
4.6 References ................................................................................................... 124
CHAPTER 5 Non-uniform Shrinkage in Composite Steel-concrete Slabs Prepared
with RCA ........................................................................................................... 127
5.1 Introduction ................................................................................................. 127
5.2 Experimental Programme ............................................................................ 128
5.2.1 Overview .......................................................................................... 128
5.2.2 Design parameters ............................................................................ 128
5.2.3 Preparation of the specimens............................................................ 130
5.2.4 Instrumentation layout ...................................................................... 131
5.2.5 Material properties ........................................................................... 131
-ix-
The University of Sydney
5.3 Experimental Results and Discussions ........................................................ 137
5.3.1 Nonlinear RH loss distributions ....................................................... 137
5.3.2 Long-term strain measurements ....................................................... 142
5.4 Numerical Simulation .................................................................................. 151
5.4.1 Numerical models ............................................................................. 151
5.4.2 Validation of numerical model ......................................................... 154
5.4.3 Comparisons of the influence between non-uniform and uniform
strain profiles on composite slabs curvatures ........................................... 154
5.4.4 Influence of RCA on composite slabs curvatures ............................ 156
5.4.5 Simplified approach for the estimation of non-uniform shrinkage .. 158
5.5 Conclusions ................................................................................................. 159
5.6 References ................................................................................................... 160
CHAPTER 6 Long-term Behaviour of Simply-supported Composite Steel-concrete
Slabs with RCA ................................................................................................. 162
6.1 Introduction ................................................................................................. 162
6.2 Experimental Programme ............................................................................ 163
6.2.1 Material............................................................................................. 163
6.2.2 Concrete mixtures and fresh concrete property ............................... 164
6.2.3 Mechanical properties of hardened concrete .................................... 165
6.2.4 Mechanical properties of steel ......................................................... 167
6.2.5 Preparation of composite slab specimens ........................................ 169
6.3 Experimental Results ................................................................................... 171
6.3.1 Non-uniform shrinkage profiles ....................................................... 171
6.3.2 Long-term deflections ...................................................................... 173
6.4 Modelling .................................................................................................... 176
6.4.1 Numerical model .............................................................................. 177
6.4.2 Material properties ........................................................................... 178
6.4.3 Comparisons between numerical and experimental results ............. 179
6.5 Parametric Study ......................................................................................... 183
6.5.1 Studied composite slabs ................................................................... 183
6.5.2 Results and analyses ......................................................................... 185
6.6 Design Considerations ................................................................................. 194
6.6.1 Design procedures ............................................................................ 194
6.6.2 Validation of the proposed design procedures ................................. 195
-x-