Properties of multi-strength grade EPS concrete containing silica fume and rice husk ash

This paper aims to study the possibility of producing multi-strength grade lightweight concrete containing expanded polyethylene beads and evaluate their mechanical and durability characteristics. To this aim, various mixtures are produced by replacing 0%, 15%, 25%, 40% and 55% of natural aggregates volume with EPS beads, substituting cement with 10% silica fume (SF) or 20% rice husk ash (RHA), and adding waste propylene fibers in the percentage of 0.1, 0.3, 0.5 and 1 of cement volume (0.013%, 0.038%, 0.063% and 0.127% of concrete volume). These mixtures are evaluated through a comprehensive test program including measuring compressive strength, splitting tensile strength, flexural strength, ultrasonic pulse velocity, drying shrinkage, water absorption and electrical resistivity. Generally, application of EPS beads decreases the strength properties; however, the results show the potential of EPS beads for producing structural grade, moderate strength grade and insulating lightweight concrete. Mixtures containing 15% EPS beads and 20% RHA as well as 25% EPS beads and 10% SF show acceptable strength and density for structural lightweight concrete. In addition, application of 40% and 55% EPS beads lead to the moderate strength grade and insulting lightweight concrete respectively. These results accompany by an improvement in electrical resistivity, and increase in water absorption and drying shrinkage. Moreover, except for toughness, addition of waste fibers has not improved lightweight concrete properties.