Mechanical behavior of concrete block masonry : influence of vertical joint

Abstract

The main objective of this study is to verify, through compression tests on different prisms, the vertical and horizontal deformability and the failure modes of the components of concrete blocks under compression. In this study two mortar mixes were tested, according to the recommendations of BS-5628 1992, along with two types of prism, with and without the presence of a vertical joint. The conclusions were: the appearance of non-linearities of the masonry corresponds to an increase in the lateral strain due to extensive cracking of the material and a progressive increase in the Poisson ratio; the cracks in the three-block prisms built with the mortar type I were vertical, occurring symmetrically on both sides; the prisms built with mortar type II had, as a consequence of localized crushing, an association with vertical cracks due to the concentrations of stresses at some points; the presence of a vertical joint led to the appearance of separation cracks between the middle block and the vertical mortar joint, when the stress reached approximately 30% of the compressive strength of the set; the prisms with two whole blocks and one vertical joint (B) built with the mortars of mixes I and II had a compressive strength of the order of 42% and 66% of the prisms with three whole blocks (A), respectively.