Impact of Moisture Content on the Compressive and Shear Behavior of Autoclaved Aerated Concrete Masonry

Abstract

The compressive and shear bond strengths between the masonry units are the most important factors in determining the overall strength of an infill wall. The compressive and shear bond strength of autoclaved aerated concrete (AAC) or autoclaved cellular concrete (ACC) is heavily influenced by its porosity, density and moisture content. Because ACC has more porosity and water absorption than standard clay brick, customers and designers of ACC are sometimes worried about the formation of cracks at high water contents. As a result, an experimental study was conducted to analyze the compressive and shear behavior of ACC brick units, cement mortar, and masonry with reference to three diverse moisture conditions (1) oven-dried, (2) air-dried, and (3) wet conditions. In this investigation, three distinct mortar mixes were considered, each characterized by cement-to-sand ratios of 1∶2, 1∶4, and 1∶6. Prior to setting the cement sand mortar in the brickwork, a thin layer of cement slurry was applied to the block surface. The compressive behavior of ACC masonry was assessed using masonry prism specimens made of four layers of bricks and three mortar joints, whereas the shear bond strength of ACC was assessed using masonry triplets made of three layers of brick and two mortar joints. Throughout the study, the mortar thickness of 10–15 mm was maintained. The average of two prism and triplet specimens was used for all the masonry compressive strength and shear bond strength data reported in this investigation. The experimental results indicate that moisture content has a substantial impact on the compressive and shear bond strengths of ACC. Increasing moisture content will significantly decrease the compressive strength of ACC brick units, cement mortars, masonry prisms, and shear bond strength of masonry triplets. For a wet masonry prism, mortar with designations 1∶2, 1∶4, and 1∶6 had average strength reductions of 49.74%, 54.97%, and 59.85%. The average strength drops for mortar with 1∶2, 1∶4, and 1∶6 ratios in wet masonry triplets was 44.3%, 61.1%, and 62.5%, respectively.