Fresh and mechanical characterization of fly ash/slag by incorporating steel fiber in self-compacted geopolymer concrete

Abstract

Industrial waste management and CO2 eradication are major environmental issues. For every ton of production of OPC, one ton of carbon dioxide is produced. Creating sustainable concrete from industrial waste is vital. Geopolymer makes sustainable concrete since its binder is fly ash, not cement. This research examines the effects of steel fibers and fluid-to-binder ratio on self-compacted geopolymer concrete. The experimental investigation used steel fibers volume fractions of 0%, 0.5%, and 1% (by concrete volume) and fluid to binder ratios of 0.6, 0.7, and 0.8. When creating the alkaline activator, the ratio of Na2SiO3 to NaOH is taken as 3. Self-compacted geopolymer concrete requires a high dose of super plasticizer (6% to 7%), however this research obtained the same characteristic with just 2% super plasticizer by binder weight. Flowability, filing ability, and passing ability are used to evaluate fresh state properties, whereas compressive and split tensile tests are used to assess hardened state properties. As steel fibers content grows from 0% to 1.0%, concrete workability diminishes. After 0.5% steel fibers, compressive strength stabilizes. Increasing steel fibers dosage from 0% to 0.5% and from 0.5% to 1.0% increases tensile strength because of the steel fibers interlocking with one another. Workability is improved by increasing the alkaline solution to fly ash ratio, but compressive and tensile strength are reduced. This is due to the fact that when alkaline solution to fly ash ratio increases, concentration of fly ash decreases as the volume of alkaline solution and liquid increases. The tendency of bleeding and segregation occur at an “alkaline solution to fly ash ratio” 0.8, resulting in very low mechanical strength; however. A balance is observed in workability and mechanical property at alkaline solution to fly ash ratio of 0.6 and 0.7 for SCFRGPC.