Effect of Fly Ash and Indus River Sand on Mechanical, Durability and Environmental Performance of Autoclaved Aerated Concrete (AAC)

Nowadays construction industry is trying to develop energy-efficient and environmentally friendly materials.In this regard, various types of concrete are designed but still, there is a need for a material that is energy efficient and sustainable, one of which is Autoclaved Aerated Concrete (AAC).Therefore, this study utilizes various waste products locally available to produce lightweight (AAC).This research work focuses on reducing Carbon Dioxide release with the help of cement substitutive substances like Fly ash (FA) in Autoclaved aerated concrete (AAC).The main objective of the present study is to investigate the mechanical and durability performance of AAC by adding FA and Indus River Sand (IRS) as substitutes for cement and fine aggregate respectively.Various percentages of Fly ash (5, 10, 15, 20, 25, and 30%) and Indus River sand (25, 50, 75, and 100%) were used as replacements for Cement Type I and Fine aggregate in AAC.Afterward, this concrete was cured in an Autoclave machine for curing period of 9 hours.In the end, various tests i.e. compressive strength, split tensile strength test, dry density, embodied carbon, and embodied energy of AAC were conducted to check the influence of both materials as replacements on the performance of concrete.Test results show that the maximum compressive strength of 2.01 MPa was achieved at an optimum percentage of FA, which is 20%.Moreover, at 100% replacement of IRS compressive strength was further increased to 2.29 MPa.Similar trends were achieved in the case of split tensile strength increase.Furthermore, durability in terms of embodied carbon and embodied energy was also checked and it was found that embodied carbon and embodied energy were decreased by 21.6% and 27.5%.It was revealed from test results that using an optimum percentage of FA and Indus River sand enhances both the mechanical and durability performance of AAC due to the filling effect of FA and IRS.