Comportamento tensão-deformação de prismas de alvenaria com argamassa de assentamento de baixa resistência e elevado teor de ar incorporado

Abstract

Structural masonry is an important and competitive construction system, as it is rational, flexible, fast and efficient. Despite being one of the oldest construction processes, only in recent years has this system been boosted and improved, becoming an advantageous alternative for residential buildings. Thus, the behavior of masonry under compressive stresses has been the subject of several studies, seeking to estimate and provide equations that represent the behavior of these elements until the failure process. Masonry is a composite formed by the combination of blocks and laying mortar. And, as new materials are being developed, analyzes are necessary for the characterization of these new composites. For these reasons, the analysis of the interaction between the block and the different types of mortar that are available in the market is important to have a greater domain over the variables that interfere in this rupture and to understand the restrictions of each type of combination. Thus, the objective of this study is to evaluate stress behavior versus specific deformation of compressed prisms molded with stabilized low strength mortars, of 36 and 72 hours, and bagged mortar, combined with concrete and ceramic blocks, with hollow and solid walls. For this, physical and mechanical characterization tests were carried out on all materials used in the research according to Brazilian standards. To verify the deformability of the compressed prisms, prisms of two blocks were molded, instrumented with two LVDT's, glued on opposite faces, to measure the deformations. It was concluded that low resistance mortar prisms with high incorporated air content combined with concrete blocks showed a linear behavior close to stresses of 4 MPa, which from that level onwards behaved with stress relaxation and proportional deformations until they reached rupture. Pore collapse was also observed, with the destruction of the mortar pores to levels where the stress had not yet reached the maximum rupture. In the prisms of hollow wall ceramic blocks, as the resistance of the mortar increased, there was also an increase in the resistance factor between the prism and the block and in prisms with solid wall ceramic blocks and concrete blocks, there was an increase in this factor as it increased. the content of entrained air.