Estudo das propriedades mecânicas do concreto com adição de cinza de casca de arroz

Abstract

The thermal curing is a process used to accelerate the hydration reactions of the Portland cement in mortar and concrete elements, in order to achieve gains in mechanical strength at early ages, since the temperature acts on the degree of these reactions. On this way, it is important to assess the mechanical behavior of con-cretes with mineral additions. The rice husk ash (RHA) is a residue that lies among the most studied addi-tions in the concrete composition. The reuse of RHA besides reduce the environmental problems, can cause an increment on the mechanical strength of mortars and concrete, even when is used in partial substitution of Portland cement. This paper presents experimental results of the compressive strength, of the tensile strength (obtained by the split test), and of the modulus of elasticity for concrete prepared with RHA, incorporated into the mixture at dosages of 5% and 10% (by mass), in substitution of the cement. The RHA was produced through the uncontrolled burning of rice husk. The concrete mixtures were defined from an evaluation of the mechanical properties of specimens that were made with and without the addition of RHA. The process of thermal steam curing of the concrete was developed in cycles of 6 hours, at a constant temperature of 80° C. The results showed higher strengths for specimens that were made with the addition of RHA.