Effect of high temperature on the strength and thermal conductivity of glass fiber concrete

This research selected a water-cement ratio of 0.5 and a slump of 18 cm for an ACI mix design, and used 0.60 and 2.54 cm glass fibers of 0.5%, 1.0% and 1.5% of cement by weight, respectively, to discuss the effect of one hour high temperature (440, 500, 580, 800 and 1000 °C) on the compressive strength and thermal conductivity of concrete. The results show that the additional amount of glass fibers used for enhancing the compressive strength of the concrete should be appropriate. When short glass fiber is added to concrete, the flexural strength of concrete will be reduced when the amount of fiber is too large; when the length of glass fiber added to concrete is long enough, the flexural strength of concrete will increase with the increase of the amount of fiber. Under the effect of high temperature, the residual compressive strength of concrete increases with the amount of glass fibers added and increases with the glass fiber length. The thermal conductivity is lower than the concrete of the control group; the decrement increases with the amount of glass fibers added and increases with the glass fiber length. Temperatures of 400–500 °C have the greatest effect on the decrease of thermal conductivity. Temperatures of 500–580 °C have the second greatest effect on the decrease in thermal conductivity.