Influence of the grout and rebar in the masonry compressive strength

Abstract

The present research will do an experimental investigation of the grout and rebar quantity influence on the final compressive strength of concrete blocks masonry. In this way, it will be developed an experimental program subdivided in four steps.Initially, it will be accomplished tests to determine the physical and geometrical characteristics of the blocks as well as their compressive strength in accordance to the NBR-7186. The blocks will be collected direct on the factory, with expected mean strength values of 8 and 15 MPa (denoted as B1 and B2).On the second step, it will be mounted six prisms for each kind of used blocks. After that, they will be grouted, using for that two kinds of grouts (denoted as G1 and G2), and then, combining each kind of block with each kind of grout, and adopting three specimens for each of these combinations, resulting in a 18-specimen-test program.On the third step, it will be mounted grouted prisms with three distinct quantity of rebar, resulting on 18 prisms for each kind of block, which will be combined with two classes of grout and the three rebar quantity, totalizing thirty six prisms in this step.On the fourth step, it will be tested small walls made of three blocks length and five courses high. All specimens will be executed with the aid of appropriate tools in such a way to minimize the effects of labor, controlling so, with more efficiency, parameters like plumbing and leveling.From the prisms results, it will be obtained an efficiency ratio between plain prisms and grouted ones, for each kind of blocks. After the adoption the greatest efficiency ratio it will be defined which combinations will be reproduced on the wall’s tests, for each block type.Thus, on the fourth step, it will be executed and tested 10 walls for each kind of block, being these specimens subdivided in plain walls, totally grouted walls and walls grouted with the three different rebar quantity, totalizing 20 walls.The strains on the blocks will be monitored by electrical strain-gages, and the prisms will have their strains monitored by displacement transducers as well as with strain-gages on the blocks in their mid course. For the reinforced prisms, additionally, it will be used strain-gages on some rebar, and such procedure will be repeated on the wall’s tests.The obtained results will be presented in the form of tables and graphs, with the commentaries and observation considered important, in a way to facilitate the reading and comprehension of the final report. (AU)