Enhancing performance of infill masonry with latex modified mortar subjected to cyclic load

During the times of eathquakes, reinforced concrete (RC) frames with infill masonry generally fail due to reasons like diagonal tension, shear, corner crushing, etc. Bond failure is a predominant type of failure that leads to failure of the infill wall. Experimental investigations were carried out in this study to enhance the bond strength of mortar using styrene-butadiene rubber as an additive. Experiments are conducted on cement mortar with various percentage additions of latex with mortar. The percentage of latex was varied in water from 0% to 30% in steps of 5%. Tests were conducted on three mortar mixes, 1:3, 1:4 and 1:5. The optimum percentage of latex based on mortar compressive strength was found as 20% and the performance is satisfactory for 1:3 mix but not satisfactory for 1:5 mix. Hence, it is concluded that the optimum dosage of rubber was found to be 20% based on the compressive strength of the cement mortar cubes. Cyclic tests on infill walls without latex modified rubber and with latex modified rubber showed that addition of latex in mortar increased pre-yield stiffness, ductility ratio by 13% and energy dissipation capacity by 46%.