“Experimental Analysis of Bond strength of Autoclaved Aerated Concrete Masonry with regards to Mortar Ratio and Mortar Thickness”

Abstract

Autoclaved aerated concrete (AAC) blocks are commonly used for masonry walls. It is essential to assess the bond strength of the block-mortar interface for the AAC masonry walls in order to assess its tensile and shear bond strength under various mortar combination. This research investigates the bond strength of AAC block mortar interface made up of a) polymer modified mortars (PMM) and b) ordinary cement sand mortar of 1:4 and 1:6 mix of thickness 10mm,15mm and 20 mm respectively. A thin cement slurry coating was applied before placing the cement sand mortar in the masonry. For all types of interface, shear bond strength of masonry was studied using a triplet test, while the tensile bond strength was determined through a cross-couplet test. Among the cement sand mortar used in this study, cement sand mortar of ratio 1:4 and thickness 15mm showed the maximum shear strength of 0.13 MPa with the failure of blocks as the predominant failure while the PMM had shear bond strength of 0.12 MPa with the failure of blocks as the predominant failure type. However, in case of the tensile bond strength testing, PMM showed the tensile bond strength of 0.19 MPa, which was highest among all the test specimens used in this study. Considering both the tensile and shear bond strength of the AAC masonry based on the failure pattern, among all the combinations used in the experiment, either PMM or cement-sand mortar of ratio 1:4 and thickness of 15mm can be chosen for the AAC masonry.