EFFECT OF VISCOSITY MODIFYING AGENTS ON PERFORMANCES OF CONCRETE

Abstract

This study emphasizes the effect of viscosity modifying agents (VMAs) on
performance of concrete. The performances of concrete were evaluated in
terms of the bleeding and compressive strength of concrete. Additionally, the
influence of the VMAs on dewatering of mortar under high pressure was also
investigated. Two different types of VMA, namely surfactant and starch ether
were used with a fixed dosage of polycarboxylate based superplasticizer in the
tested mixtures. All mixtures of concrete and mortar were prepared with the
same water to binder ratio at 0.39. Experimental results showed that surfactant
type VMA significantly reduced the bleeding, dewatering and slightly reduced
the compressive strength of concrete. Whereas the use of starch in concrete
mixtures moderately reduced bleeding, slightly reduced the compressive
strength of concrete and was ineffective to reduce the dewatering of mortar
under high pressure.