Elevated Temperature Properties of Bamboo Shaving Reinforced Geopolymer Composites

Abstract

Geopolymer is a new alternative cement binder to produce concrete. In the present study, a novel geopolymer composites containing bamboo shaving (0–2 wt.%) were fabricated and exposed to the temperatures of 200°C, 400°C, 600°C and 800°C. Physical properties, micro-structure, and mechanical strengths of the geopolymer composites were evaluated before and after heating in order to understand their thermal properties, which are essential for the use as building materials. As the temperature rises, the drying shrinkage and apparent porosity of the composites increase, while the compressive and bending strengths decrease. At the temperature range of 200°C–800°C, the residual compressive strength rates of the geopolymer composite containning 2 wt.% bamboo shaving were respective 73.8%, 61.47%, 56.16%, and 29.56%, meanwhile, the residual flexural strength rates were respective 46.69%, 8.68%, 2.52%, and 2.33%. Correspondingly, the residual compressive strength rates of pure geopolymer were respective 72.81%, 61.99%, 54.55%, and 14.64%; the residual flexural strength rates were 48.87%, 5.69%, 3.22%, and 2.47%, respectively. Scanning electron microscope (SEM), optical microscope, and X-ray diffractometry (XRD) were applied to find the microscopic changes. The strength loss in the geopolymer composites was mainly because of the thermal degradation of bamboo shaving and shrinkage of geopolymer matrix. Bamboo shaving has great potential as reinforcer in developing low-cost geopolymer composites and may be used for applications up to 400°C.