Influence of the Mortar Bedding in Compressive Strength of Masonry Wallets made of Brazilian Concrete Blocks

Mortar bedding is a high cement-based material placed between concrete blocks and can improve the tensile and shear strength of the joints. Two types are recommended, full bedding, which covers the entire liquid area of the block, and face shell bedding, where the mortar is placed only on the longitudinal walls of the block, forming a lateral cord. The union of the lack of technical regulation on the choice of the laying pattern and the execution of a wall by more than one professional, in some cases, results in the appearance of a third pattern, mixed bedding, the rows mix the full bedding and the face shell bedding types. This paper aims to evaluate the influence of the mortar bedding on the mechanical behavior of the structural masonry, where walls of concrete blocks with face shell and full and mixed bedding were made, evaluating their respective failure modes. The inputs of the wall and the structures of each proposed bedding type were individually studied and subjected to the compressive strength test. Some LVDTs have been used to evaluate and compare the displacements between patterns. In addition, the failure modes in each type of mortar bedding were analyzed. The results of the compression tests of the walls showed that the type of laying significantly influences the compressive strength of the masonry, with the face shell and mixed bedding patterns showing a loss of capacity of compressive strength in relation to the full bedding of approximately 18.5% and 21.7%, respectively. In addition, it was noted that in addition to being less resistant, the mixed pattern failed at the end of the elastic zone, demonstrating a brittle behavior. Given the facts, the full and face shell bedding is indicated; the face shell bedding is used with caution, considering its reduced load capacity and failure mode, when dimensioning the masonry.