Induced shear in reinforced concrete beams with synthetic aggregate

Cisalhamento induzido em vigas de concreto armado com agregado sintético

Abstract

The increasing aluminum production demands larger volumes of bauxite residue (BR) to be stored in the Amazon region. There are millions of tons of waste without reuse but with high potential for use in civil construction as artifacts or components for concrete. Due to the significant consumption of coarse aggregates for concrete, there is the possibility of producing synthetic aggregate (SA) from bauxite residue, containing high levels of residue (70%, 80% and 90%), maintaining satisfactory levels of resistance and durability. To evaluate this new product, two beams were made with conventional aggregate (gravel) and the others with SA. For the evaluation of the shear strength, friezes were made to fix the failure surface, aiming to reduce the influences of the arch action on the shear strength, inducing the failure in the brittle section. The friezes presented inclinations of 30° or 45°, according to the calculation models of the Brazilian code for concrete structures. All beams were subjected to bending test until failure. The results showed that the SA has potential for use in reinforced concrete structures, presenting a similar performance to the conventional aggregate. The results also showed the preponderance of tensile when the a/d ratio increases, evidencing the greater contribution of the coarse aggregate with the increase of the strut inclination.

Keywords:
shear; beams; reinforced concrete; bauxite residue; Amazon