The effect of in situ polymerization on the chloride diffusion and microstructure of polymer-Portland cement pastes and mortars

A polymer-cement system was produced by in situ polymerization of vinyl sulphonate in Portland cement pastes and mortars. The effects of the polymer on strength, chloride diffusion and microstructure were studied. The presence of polymer was found to be extremely effective in reducing chloride diffusion, but was accompanied by a reduction in strength. The addition of silica fume in combination with the polymer was found to be effective in mitigating the reduction in strength, while providing additional benefits with regard to chloride diffusion. The beneficial effect of the silica fume wasfound to be associated with its influence on the polymer phase, which became more coherent and more compatible with the matrix.