Thesis (PhD (Civil Engineering))--University of Stellenbosch, 2007. / ECC (Engineered Cement-based Composites) is a type of HPC (High Performance
Concrete) that was engineered to overcome the weaknesses of ordinary concrete. It
shows high ductility as it can resist the full tensile load at a strain of more than 3 %.
This superior response is achieved with multiple cracking under tensile loading which
has a pseudo strain hardening phenomenon as result.
The purpose of the research project reported in this dissertation is to investigate
and characterise the time-dependant behaviour of ECC and create a constitutive model
to numerically simulate the static and time-dependant behaviour of ECC.
To investigate the time-dependant behaviour experimentally, rate and creep tests
were done on the meso- and macro-level while rate tests were done on the structurallevel.
The meso-level was represented by the pull-out testing of fibres embedded in
the cement-based matrix and direct tensile tests were done for the macro-level.
Flexural tests on thin beams were done to simulate the structural-level.
Strong time-dependant behaviour was found on all three these levels. On the
meso-level, the most prominent finding is that the failure mechanism can change with
a change of strain rate, i.e. fibre pull-out at a low pull-out rate, while with a high pullout
rate, fibre rupture can occur. Even though the strength of a tensile specimen on
the macro-level showed a dependence on the strain rate, the ductility remained
constant over four orders of magnitude of the strain rate. On the structural-level,
however, a reduction of the flexural ductility was found with an increase of the ...
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/1249 |
| Date | 03 1900 |
| Creators | Boshoff, William Peter |
| Contributors | Van Zijl, G. P. A. G., University of Stellenbosch. Faculty of Engineering. Dept. of Civil Engineering. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 14176778 bytes, application/pdf |
| Rights | University of Stellenbosch |
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