UBC Theses and Dissertations
Durability performance of eco-friendly ductile cementitious composite (EDCC) as a repair material Du, Yang
The objective of the experimental program in this thesis is to investigate the durability performance of Eco-friendly ductile cementitious composite (EDCC), a newly developed repair material for seismic retrofitting. Several aspects of the durability performance of EDCC were investigated in this work, in terms of restrained shrinkage resistance, freeze and thaw resistance and bond strength degradation before and after environmental exposure. All the tests focused on repair overlay and substrate composite assembly. Six different EDCC fiber mixes were involved in the testing to discover the best mix in terms of performance and economical aspects. The substrate of the composite assembly includes concrete, masonry blocks and clay blocks. EDCC can be applied on different substrates by hand casting and spraying. EDCC application on concrete substrates employing the hand casting process is used to explore the durability performance of EDCC. Clay and masonry substrates, along with the spray application process, are only used to compare the influence of different application methods on the bond strength based on the bond strength data obtained in Yuan Yan’s thesis. After the whole experimental program, regarding hand applied process, both 2% PVA and 1% PVA and 1% PET hybrid mix yields to the best durability performance. In spray process, clay substrate specimens give better bond strength than the specimens prepared through hand applied process, however, masonry specimens show lower bond strength than hand applied specimens. Overall 1% PVA and 1% PET will be recommended for future seismic retrofitting application due to lower cost compared to 2% PVA EDCC. It is noted that the performance of EDCC depends greatly on good material mixing for different application processes. In order to obtain a good EDCC mix, a rigorous mixing procedure should be followed. Hence, future in-situ applications should guarantee a proper mixing procedure for good quality control. The spray process was found to be very successful with very little rebound and nearly no material sloughing off. The results of the experiments done in this study indicated that the spray process increases the material application speed to further reduce potential high labor cost.
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Attribution-NonCommercial-NoDerivatives 4.0 International