Abstract

Some environmental issues are industrial wastes and cement productions, which cause high gas emissions. Cement is vital in the global construction industry. The research goal was to find a cheaper material locally. Using OPC, calcined Montmorillonite clay powder (CMMT) and waste Khat Husk Ash (KHA) were tested as a partial replacement. Water entering the interlayer molecular spaces and adsorption, a material in expansive soil, causes Montmorillonite clay to expand more than other clays. Most of Ambo's land is expansive soil, from which samples were taken to determine Montmorillonite clay content. The average temperature required to calcine MMT clay was performed at 800℅ using a muffle furnace, ground to the fineness of 150μm, and its chemical composition was investigated. Similarly, the waste KH was heated at a temperature of 600℅ . The proportions by weight are applied for the OPC, Calcined MMT clay powder and Waste Khat Hush Ash as follows: Proportion-A (100%: 0%: 0%); P-B (85%:10%:5%); P-C (75%:20%:5%); P-D (65%:30%:5%); P-E (55%:40%:5%) and P-F (45%:50%:5%). The production of concrete for the C-25 Grade mix design was performed based on the ASTM manual, ERA manual, and the ACI code to evaluate the strengths and durability of concrete. These materials were calcined and then tested for strength and durability using ASTM C 618-5 to determine the chemical compounds at various temperatures. The experiments used aggregates up to 25mm in size. The results showed that when OPC was partially replaced with Calcined MMT clay powder and KHA, the consistency and setting time remained within the ASTM C-191 Standard Specifications. Moreover, the compressive, flexural, and split tensile strengths gradually decreased from the control specimen as the replacement was increased. The optimal amount of calcined MMT clay powder and Waste KHA indicated up to 15% by weight to replace OPC content in normal concrete mix production. The benefit cost analysis revealed that using OPC with calcined MMT clay powder and KHA is more cost-effective than using OPC alone.