Avaliação do efeito do fator água/aglomerante em concreto de alto desempenho

Abstract

Concretes with higher strengths than conventional concrete have been the subject of research mainly due to properties associated with durability and mechanical performance. For these types of concrete, some factors must be throughly analyzed and used efficiently, such as the quality of the materials, the mixing method, the degree of density and porosity, the amount of water, that is, factors wich may affect the concrete strength and microstructure. This work aims to verify the effects of the water/binder ratio variation on the compressive strength, porosity and microstructure of concrete samples developed with the same composition as an ultra high performance concrete mix. The concrete was developed with Portland cement, sand, quartz powder, silica powder, superplasticizer and different water/binder ratios. The samples were characterized by X-ray diffraction, by scanning electron microscopy and pore volume. The mechanical strength was verified by compressive strength test at 7 and 28 days. The concret produced as an ultra high performance concrete mix was considered as high performance concrete due to the presented resistance range, 60 - 100 MPa.