Thermal and structural behaviour of basalt fibre reinforced glass concrete

摘要

This study aims to produce a type of concrete with both good thermal and mechanical properties by using environmentally friendly and low cost materials. In addition, the resistance of this concrete to fire conditions was investigated. The experimental work comprises two parts. In the first part, recycled glass was used as a partial replacement for natural sand (at proportions 20%, 40% and 60%) together with basalt fibre having different volume fractions (0.1%, 0.3%, and 0.5%). The results obtained from the experimental work showed that the optimum content is 20% glass and at 28 days, there was a 4.23% and 15% enhancement in the compressive strength and the splitting tensile strength respectively. Above 20% glass there was a slight reduction (6.6% and 22%) in the compressive strength and the splitting tensile strength when 60% glass was used. The results also showed that when glass sand and basalt fibre content increase, there is a decrease in the thermal conductivity range from 4.35% to 50% at temperature levels between 60oC to 600oC. The structural behaviour of this type of concrete was investigated in the second part of this study by carrying out small-scale slab tests at ambient and elevated temperatures. The results show that there is an increase in the load carrying capacity above the theoretical yield line load, due to membrane action, for all percentages of glass and volume fractions of basalt fibre ranging from 1.35 to 1.68 for the slab tested at ambient temperature and from 3.13 to 3.26 for the slabs tested at elevated temperature. Also the slabs with higher glass sand and basalt fibre content had a higher load enhancement and failed at a higher displacement compared to the control mix.A comparison between the simplified method and the finite element software package ABAQUS showed that the ABAQUS model gives reasonable predictions for the load-vertical displacement and the temperature-displacement relationships at both ambient and elevated temperature conditions, while the simplified method gives conservative predictions for the maximum allowable vertical displacement for the slab at elevated temperature. A parametric study showed that a 10 mm cover depth is the optimum depth as well as the reinforcement temperature predicted reduced with increasing load ratio (applied load/yield line load).