VAE乳胶粉/碳纤维复合改性混凝土的力学性能

Mechanical Properties of VAE Latex Powder/Carbon Fiber Co-modified Concrete

为探究醋酸乙烯酯-乙烯共聚物(VAE)乳胶粉和碳纤维对混凝土力学性能的混杂改性效果及机理,制备了1种VAE乳胶粉改性混凝土(VAEMC)、3种碳纤维改性混凝土(CFMC)和3种VAE乳胶粉/碳纤维复合改性混凝土(VAE/CFMC),测试了改性混凝土的电阻率和力学性能,并进行了扫描电镜试验和压汞试验.结果表明:VAE乳胶粉可以促进碳纤维的分散,VAE/CFMC的电阻率小于CFMC;与CFMC相比,VAE/CFMC的力学性能更佳;VAE乳胶粉与碳纤维具有“正混杂效应”,复掺VAE乳胶粉与碳纤维时,混凝土的力学性能呈现出“1+1>2”的复合增强效果;VAE乳胶粉可以优化CFMC的孔隙结构,细化其孔径,增强碳纤维/混凝土基体界面的物理结合,使碳纤维的破坏形式由拉滑破坏转变为拉断破坏.

To explore the hybrid modification effect of vinyl acetate-ethylene copolymer(VAE)latex powder and carbon fiber on mechanical properties of concrete and its mechanism,one kind of VAE latex powder modified concrete(VAEMC),three kinds of carbon fiber modified concrete(CFMC)and three kinds of VAE latex powder/carbon fiber co-modified concrete(VAE/CFMC)were prepared.Their resistivity and mechanical property were tested,and scanning electron microscope test and mercury intrusion porosimetry test were carried out.The results show that VAE latex powder can promote the dispersion of carbon fiber,and the resistivity of VAE/CFMC is lower than that of CFMC.Compared with CFMC,VAE/CFMC has better mechanical property,VAE latex powder and carbon fiber have positive hybrid effect.When VAE latex powder and carbon fiber are co-incorporation,the mechanical property of concrete is better than addition of the two components.VAE latex powder can improve the pore structure of CFMC,refine its pore size,reinforce the physical bond of carbon fiber/concrete matrix interface,and change the failure mode of carbon fiber from pull slip to pull break.