EFFECT OF POLYVINYL ALCOHOL ON FLEXURAL STRENGTH AND SOME IMPORTANT PHYSICALPROPERTIES OFPORTLAND CEMENT PASTE

Abstract: This work was designed to investigate the simultaneous effect of both water-to-cement (W/C) and polymer-to-cement(P/C) ratios on flexural strength of type V Portland cement pastes containing polyvinyl alcohol. The obtained resultsconfirmed the strong effect of W/C-ratio on the effectiveness of the added polymer so that there exist optimum valuesfor both W/C and P/C-ratios. Pastes prepared at optimum W/C and P/C-ratios of respectively ۰.۳۰ and ۰.۰۱۶ exhibitedthe highest flexural strength which was more than two times the strength of unmodified pastes. Further measurementson hardened paste specimens prepared at W/C=۰.۳۰ show that increasing the P/C-ratio increases dry bulk specificgravity of the specimens and result in significant reductions in both total permeable pore volume and water absorptionof the specimens confirming the effective packing caused by polyvinyl alcohol acetate.Some water-soluble polymers have proved potentials for improvement in properties of Portland cements.