Effect of wheat straw ash on mechanical properties of autoclaved mortar

This study investigates the effect of wheat straw ash (WSA) on the mechanical strength of autoclaved mortar. The mechanical properties studied include compressive, tensile, and flexural strengths of mortar. Mortar mixes were prepared using natural silica, wadi (local sand), and crushed limestone fine aggregates at a w/c ratio of 0.6. Mortar specimens were exposed to autoclave for 2.5 It at a pressure of 2 MPa. Three percentages of WSA replacement levels (3.6%, 7.3%, and 10.9%) by weight of sand were utilized in the study, The study showed that the replacement of sand by WSA increases the mechanical strength of autoclaved mortar. Mortar specimens containing limestone aggregate with 10.9% WSA replacement level showed an average increase in compressive, tensile, and flexural strength by 87%, 67%, and 71%, respectively, compared to control mortar specimens. Scanning electron micrographs for autoclaved paste specimens containing 7.3% WSA replacement level revealed a more packed structure compared to control paste specimens. (C) 2002 Elsevier Science Ltd. All rights reserved.