Análise do modo de ruptura e previsão de resistência à compressão de prismas de alvenaria estrutural de blocos cerâmicos e de concreto

Abstract

The biggest challenge of structural masonry is to correlate the set bedding mortar-block and transform it into a ductile system, with a predictive behaviour, as these materials own properties and different compositions when analysed separately. Besides that, the brazilian current regulations of masonry does not consider, in a direct manner, that the masonry can influence in the final resistance and in the failure mode of the wall. Bearing in mind that the properties of the bedding mortar as well as the block can influence the performance of the masonry, the present work sought to evaluate the failure mode of compressive prisms, varying the type of structural block and the resistance of the laying mortar. The study was held with three different types of blocks: ceramics of massive walls, ceramics of bare walls and concrete. Each type of block was combined with three resistances of industrialized bedding mortar, being casted prisms of two blocks of height. In this regard, has been made technological laboratory tests and shootings of the prisms axial compressive tests. Also has been made compressive tests in instrumented proof bodies of the bedding mortar used for a prism molding, with the purpose of plot a material stress-strain curve and verify the beginning of the nonlinear behaviour, in other words, verify as of what tension starts to loose its bearing capacity, with the propagation of the internal cracks from the zone of paste-aggregate transition to the cement matrix. From the analysis of the results was possible to verify the influence of the proportion between the resistance to the bedding mortar compression and the block over the resistance and the way of failure of the compressive prisms, propose equations of resistance forecasts for each type of prism and ascertain that the relation liquid area/ gross area of the block interferes in the failure mode. It was observed that for the prisms of ceramic blocks the increase of the bedding mortar resistance causes a resistance increment on the prism, as well as alternates the behaviour of the failure mode. For the prisms of concrete blocks it was found that the resistance of the bedding mortar did not interfere in the ultimate resistance of the prism, but triggering the failure mode process.