Study on time-varying law of compressive strength and contractibility rate of polyvinyl alcohol engineered cementitious composites(PVA-ECC)
The long-term macro-mechanical performance of polyvinyl alcohol engineered cementitious composites(PVA-ECC)for port hydraulic structure reinforcement and repair was considered crucial.A study was conducted to investigate the time-varying behavior of PVA-ECC macro-mechanical properties by compressive strength and shrinkage tests on specimens of different ages.It is found that the flow ability of PVA-ECC with a 2%PVA content is poor,and its suitability for port hydraulic structural reinforcement required further research.Compressive strength tests reveal that the compressive strength of specimens with 1.5%and 1.8%PVA content exhibits a parabolic increase trend with their age increased.After 180 days of curing,the compressive strength of the specimens reaches 69.4 MPa and 76.1 MPa,respectively,which are 1.5 times and 1.6 times as much as the strength of C40 concrete specimens.Both of the strength values meet the requirements for the structural reinforcement.Shrinkage test shows that the shrinkage of all three types of specimens tends to stabilize after 28 days.The specimens with different PVA content have higher shrinkage compared to C40 concrete specimens,while the shrinkage of specimens with a 1.5%PVA contentis closer to that of C40 concrete specimens.Considering the better workability of PVA-ECC with a 1.5%PVA content,its compressive strength meeting the engineering requirements,and its shrinkage being closer to that of concrete,it is recommended to use a 1.5%PVA content in port engineering structural reinforcement projects.Meanwhile,equations were formulated,based on experimental data,to predict the cube strength of PVA-ECC material with different mix proportions and ages,which could be used for strength prediction of PVA-ECC material.
国家科技期刊平台
NSTL
万方数据
维普
