EFFECT OF PVA MODIFICATION ON PROPERTIES OF CEMENT COMPOSITES

Abstract

Polymers are used for modification of the cement-based composites and others building materials since the thirties of 20th century. Based on the conclusions of recent studies, it is assumed that even water soluble polymers could be used as an admixture for such modification. Currently, there exist and are exploited several possibilities for polymer modification of mortars, wood-based products or bituminous asphalts. Various options differ in the way of modification, which can be basically applied to the entire volume or just a surface, but also in the form of the polymer used – either in the form of solution or fibers. The aim of our study was to investigate the influence of volume modification by the water soluble polymers, such as polyvinyl alcohol (PVA), on the properties of cement paste and find an optimum additive. It turned out that the addition of PVA solution into fresh cement paste results in an increase of porosity and therefore a stiffness and compressive strength reduction. On the other hand, the bending strength of PVA-rich specimens was significantly higher and their water absorption decreased, which may consequently result in enhanced frost resistance.