Mechanical performance of geopolymer concrete with micro silica fume and waste steel lathe scraps

Environmental studies for solutions are among the most important agendas of the scientific world. Most of the new studies are taking into account environmental effects. However, it is interesting for the scientific world to find solutions to accumulated environmental problems, reduce harmful production, and turn wastes that cause environmental pollution into useful products. In addition to incorporating fly ash, a recognized environmentally friendly and sustainable material, geopolymer concrete utilizes micro silica fume as a binding agent. Furthermore, waste lathe scraps are introduced to enhance and safeguard the concrete's mechanical properties. During the preparation phase, significant enhancements have been identified in the workability and setting time of the concrete. A total of 16 test samples were prepared for the study. Micro silica of 0%, 5%, 10% and 20% and lathe scraps of 0%, 1%, 2% and 3% were examined. Experimental findings reveal that incorporating 5% micro silica fume resulted in notable improvements in compressive, flexural, and splitting tensile strength, with increases of 14.4%, 7.45%, and 6.18% respectively. However, higher additions of 10% and 20% were found to decrease these strengths. In contrast, the inclusion of 1% lathe scraps led to notable increases in compressive, flexural, and splitting tensile strength by 11.4%, 6.35%, and 8.23% respectively. However, the addition of 2% and 3% lathe scraps resulted in reduced capacity. The findings demonstrated that combining 5% micro silica with 1% lathe scrap provided the highest strength, with improvements of 25.7%, 14.4%, and 12.0% in compressive, flexural, and splitting tensile strength respectively. Considering the enhancements in workability, setting time, and strength observed in all the tests, the recommended optimal geopolymer mixture is 5% micro silica together with 1% lathe scrap.