The Microstructure-Mechanical Properties of Hybrid Fibres-Reinforced Self-Compacting Lightweight Concrete with Perlite Aggregate

The purpose of this paper is to determine the influence of the lightweight porous perlite aggregate and two widely used types of fibres on the physical and mechanical properties, frost durability and microstructure of self-compacting lightweight concrete (SCLC). The experimental investigation consisted of tests carried out on cubes and prismatic samples made of SCLC and fibres-reinforced SCLC with variable content ranging from 0.5 to 1% of basalt fibres (BF) and/or 0.5% of steel fibres (SF). In this study, two variable contents of fine perlite aggregate were used: 5% and 15%. The workability (the slump-flow and t500 values) in fresh state SCLCs have been done. Extensive data on compressive and flexural tensile strength in bending behaviour, frost resistance and the microstructure including interfacial transition zone (ITZ) were recorded and analysed. The hybrid fibres-reinforced SCLC with perlite aggregate showed a more ductile behaviour compared to that of SCLC without fibres. Fibres bridge cracks during flexural tensile strength test. BF successfully protected porous SCLC against frost attack, whereas SF succumbed to damage.