Effect of the curing type on the mechanical properties of lightweight concrete with polypropylene and steel fibres

This study assessed the effect of steel and polypropylene fibres at various volume contents on concrete incorporating lightweight expanded clay aggregate (LECA) and water/binder (W/B) ratios of 0.37 and 0.42. The concrete specimens were cured under six curing conditions: wet, 3-day wet, 14-day wet, air-dry controlled, air-dry uncontrolled, and 90 °C vapour. The use of lightweight aggregates in the construction industry has drawn the attention of researchers and, on the other hand, fibres with a high strain-hardening response can be used as an appropriate addition in concrete materials. In this study, the mechanical properties of lightweight concrete containing steel or polypropylene fibres were evaluated by means of compressive strength, splitting tensile strength and modulus of elasticity tests at 3, 7, 28 and 60 days. According to the results, fibre reinforced concrete mixes containing LECA, cured under 90 °C vapour curing, achieved the highest mechanical strength. In addition, the optimum contents of steel fibres to obtain the highest compressive and splitting tensile strengths of lightweight concrete were 1% and 3%, respectively.