Mechanical Characteristics of Ambient Cured Alkali-Activated Slag Concrete Exposed to Elevated Temperature

Abstract

This research work was carried out to investigate physical, mechanical and bond characteristics of Alkali Activated Slag Concrete (AASC) and compare them with those of similar Conventional Concrete (CC) at ambient temperature and after exposure to elevated temperatures. As mentioned earlier, this work includes three main phases: The first phase studied the efficiency of utilizing the hybrid cement (Ordinary Portland Cement “OPC” + Ground Granulated Blast Furnace Slag “GGBFS”) to produce Alkali Activated Concrete (AAC) at ambient curing conditions considering the effect of four important parameters (GGBFS to OPC ratio, Na2O ratio, solution modulus “Ms” and water to binder ratio “W/B”) on both workability and compressive strength using Taguchi method. Microstructure analysis using Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) was performed to investigate the polymerization products. The second phase investigated mechanical and physical characteristics of ambient cured AASC after exposure to elevated temperatures. The effect of temperatures (25, 300, 600 and 900 °C) on the ambient cured AASC and on a similar CC (for a comparison purpose) was investigated by observing the physical and mechanical changes. The effect of using polypropylene fibers (PPF) on both AASC and CC was also investigated. The third phase was designed to investigate the bond behavior between AASC and steel rebars considering some important parameters (rebar