Loading Rate Effects and Sulphate Resistance of Fibre Reinforced Cement-based Foams

Abstract

This study describes the strength, toughness and strain-rate sensitivity of fibre-reinforced cement-based foams subjected to variable loading rates. Drop-weight impact tests were conducted on beams with cast density between 475 - 1200 kg/cu.m. The study shows that under quasi-static loading, the compressive strength, elastic modulus and the modulus of rupture of plain mixes scale with the square of the relative density. On the other hand, the flexural toughness factor scaled linearly with it. Fibres were seen to increase the flexural strength at all rates of loading, regardless of cast density. Further, cement based foams were seen to be strain-rate sensitive. The resistance of cement-based foams to sulphate exposure was also investigated. Heavier cement-based foams are more susceptible to sulphate attack and perform poorly with an increase in the duration of exposure when compared to the lightest mix which showed improved responses up to 30 days of exposure due to self-healing.