Performance of Laced Reinforced Geopolymer Concrete (LRGPC) Beams Under Monotonic Loading

Abstract

This paper describes the ductility behavior of Laced Reinforced Geopolymer concrete beam (LRGPC). Laced Reinforced Concrete (LRC) construction techniques are widely used in blast resistant design and seismic resistant design of structures. LRC structural element consists of equal reinforcement in tension and compression faces along with lacings. Lacing is a form of continuous shear reinforcements as compared to the form of conventional stirrup reinforcement. It is placed in the plane of principal bending and anchored in position by means of transverse bars. LRC enhances the ductility and provide better concrete confinement. In general, ductile failure of Reinforced Concrete (RC) beams with conventional stirrups is not possible when the shear span-to-depth ratio is less than 2.5 due to the influence of severe diagonal cracking. Improved ductile failure of such members can be achieved by proper detailing of reinforcement with inclined bars in the case of normal concrete mix, and also by improving the tensile strength and ultimate strain of concrete with help of steel fibers. Portland cement (PC) is widely used as binder material for concrete in a wide variety of constructions. However, this cement is proving to be ecologically hazardous material due to its inherent high internal energy content besides occurrence of emission of large quantities of carbon dioxide during its production. Therefore, there has been search for alternative binder material. Geopolymer is a type of binder that can be obtained by activating silicon dioxide and aluminium oxides present in industrial wastes such as blast furnace slag powder and fly ash, to form inorganic polymer binder system. Monotonic load testing on two specimens with 45° lacing are conducted. Experimental results indicate that both the beams exhibit almost similar strength performance. Response of LRGPC, LRC and conventional RC beams are compared.