A study on alkali resistant glass fibre concrete and its exposure to elevated temperatures

Purpose: Cement concrete is characterized as brittle in nature, the loading capacity of which is completely lost once failure is initiated. This characteristic, which limits the application of the material, can in one way be overcome by the addition of some small amount of short randomly distributed fibers (steel, glass, synthetic). Design/methodology/approach: The present study deals with the inclusion of alkali resistant glass fibers in concrete by percentage weight of cement. The mechanical properties such as compressive strength and split tensile strength have been studied after exposing the concrete samples to elevated temperatures of up to 500°C. Water binder ratios of 0.4, 0.45, 0.5, 0.55 and 0.6 have been used to prepare design mix proportions of concrete to achieve a characteristic strength of 30 MPa. The depth of carbonation post elevated temperature exposure has been measured by subjecting the concrete samples to an accelerated carbonation (5%) condition in a controlled chamber. Findings: Conclusions have been drawn in accordance to the effect of fiber replacement and temperature increment. The concrete mixes with fiber content of 1% by weight of cement had shown better strength in compression and tension compared to the other dosages and conventional concrete (without fiber). Microcracking due to internal stream pressure reduced the mechanical strengths of concrete at elevated temperatures. Also, from TGA it was observed that the amount of calcium carbonate in samples with fiber added, post carbonation was less than the mixes without fiber in it. Research limitations/implications: The present study has been limited to alkali resistant glass fibers as the conventional glass fibers undergo corrosion due to hydration. Practical implications: The glass fiber reinforced concrete can be used in the building renovation works, water and drainage works, b ridge and tunnel lining panels etc. Originality/value: Based upon the available literature, very seldom the studies are addressing the behaviour of alkali resistant glass fiber concrete and its exposure to elevated temperatures.