Evaluation of Mechanical Properties of Autoclaved Aerated Concrete (AAC) Block and its Masonry

Autoclaved aerated concrete (AAC), a potential building material, is gaining popularity due to its lightweight, thermal insulation and sound absorption qualities. This article describes the experimental evaluation and statistical variation of useful mechanical properties of AAC and its thick mortar (a mixture of cement, sand and water) based masonry. The following properties of AAC blocks were evaluated: moisture content, initial rate of absorption, water absorption, dry density, compressive strength and tensile strength. For AAC masonry, the following properties were evaluated: compressive strength based on prism specimen test, tensile bond strength based on cross-couplet specimen test and shear bond strength based on triplet specimen test. A simple analytical model has been also proposed to evaluate the elastic modulus of masonry prism. The results indicate that there is a positive correlation between the strength of mortar and AAC masonry. The strength of AAC masonry increased with an increase in the strength of mortar. During the strength test of AAC masonry, the failure patterns were studied. The block–mortar interface failure was observed in most of the cases during the masonry bond strength test. A positive correlation was observed between masonry bond and compressive strengths. Further, a comparison of strengths of masonries made of AAC block and clay brick is presented. At the present level of manufacturing, AAC masonry cannot compete with clay brick masonry in terms of strength alone.