Influence of the type of mortar and its fresh properties on the mechanical properties of concrete blocks structural masonry for high-rise buildings

ABSTRACT

The use of concrete blocks masonry for the construction ofhigh-rise, multi-storey buildings has intensified in recent years due to the economy and good performance that gives to the enterprises. In this search for optimization of the processes, the use of new materials such as industrialized mortar has increased significantly. These mortars often contain admixtures in their composition, and their use are advantageous, since they reduce the responsibility for dosage at the construction site, making easier the management of the construction, and speeding the mix process and application. However, due to the presence of admixtures, studies indicate that these mortars, when used for laying blocks for structural masonry, may not provide adequate adhesion between the block and the mortar joint, and drastically reduces the efficiency factor and change the mechanism of rupture of masonry, into crushing of the joints. Thus, this study aims at studying the performance of industrial mortars offered in the market, as well as the mix proportion of mixed mortars usually adopted in Brazil, when used for laying structural masonry made of high strength concrete blocks (16 MPa), for construction of high-rise buildings in structural masonry. The analysis was conducted based on results of compressive strength, adhesion and the mechanism of rupture of prisms. Considering all the desired properties for structural masonry's mortars used in high-rise buildings, the main features of mortars and dosage used nowadays in Brazil do not meet the requirements to generate fully satisfactory performance of the masonry.

Keywords:
Adhesion; Structural masonry; Mortar; Industrialized mortar; Concrete block