Investigação da resistência mecânica e da capacidade de isolamento acústico de compósitos cimentícios leves contendo casca do arroz e palha da planta oryza sativa (arroz)

Abstract

In the present study, a total of ten traces of foamed cellular concrete with addition of vegetal fibers from the Oryza Sativa plant were analyzed for their mechanical and acoustic performance. Among these, a trace containing only rice husk was taken as reference, and for the others a substitution of part of the rice husk by straw was carried out in three different lengths and percentages. To verify that they were lightweight composites and to facilitate future reproductions of the material, the specific masses were evaluated in the fresh state and in the hardened state at 28 days of cure. In the mechanical analysis, the axial compression strength and the flexural tensile strength were determined at three points also at 28 days of cure. In both cases there was na increase in mechanical resistance compared to the reference trait, making evident the benefit of fiber addition. As far as the axial compression was concerned, it was verified that the straw length did not influence the performance of the composites, in addition the most promising substitution percentage was 5%. For the traction in the three-point flexion the length was also a variable that did not influence the results, as the percentage of substitution, as observed in the compression performance 5% was the amount that presented better repercussions in the material. By comparing the physical and mechanical results it was verified that the density was not a determining factor for the mechanical performance due to its small variability. The acoustic analysis was performed through an impedance tube, and although the composites presented very similar results among themselves due to the non-representativeness of the samples, it was clear that the acoustic performance is superior in relation to other materials commonly used for the same purpose.