Action of redispersible vinyl acetate and versatate copolymer powder in cement mortar

Redispersible polymer powder of vinyl acetate and versatate copolymer (VA/VeoVa) is applied to modify cement mortar. The effect of VA/VeoVa powder on physical and mechanical properties of cement mortar is investigated. VA/VeoVa powder exhibits excellent water-reduction and water-retention effects in cement mortar and improves mortar properties effectively. Due to the air-entrainment effect of VA/VeoVa powder, the air content of fresh mortar is increased and the bulk density is decreased. VA/VeoVa powder makes the compressive strength decrease, but not so significant the effect on the flexural strength is, which results in the ratio of compressive strength to flexural strength goes down sharply with the increase of VA/VeoVa powder, indicating the toughness of cement mortar is improved markedly. Furthermore, VA/VeoVa powder reduces the shrinkage rate and improves the hydrophobicity and water impermeability of cement mortar.

► VA/VeoVa powder has good water-reduction and water-retention effects in cement mortar.
► VA/VeoVa powder has air-entrainment effect in cement mortar.
► VA/VeoVa powder decreases the ratio of compressive to flexural strength to below 3.
► VA/VeoVa powder reduces the shrinkage rate of cement mortar.
► VA/VeoVa powder improves the water impermeability and anti-penetration capacity of mortar.