Evaluating the influence of temperature and fiber type on the mechanical properties of self-compacting lightweight concrete

In the present study, the effects of glass and basalt fibers (GF and BF) and temperature on the properties of self-compacting lightweight concrete (SCLC) has been investigated. For this aim, the fresh and hardened properties of 12 SCLC mixes have been investigated that contained monotype and hybrid fibers. The volume of the monotype fibers were 0.25%, 0.5%, 0.75% and 1% of the concrete volume. The hybrid fibers had volume fractions of BF/GF= 0.25%/0.75%, 0.5%/0.5%, and 0.75%/0.25%. The self-compacting properties of SCLC was assessed by means of slump flow, T500, V-funnel and J-ring. After 28 days of curing, the compressive, splitting tensile and flexural strengths tests were performed to characterize the mechanical properties of SCLC at room temperature of 20 °C and high temperatures of 100 and 300 °C. The test results of fresh concrete showed that all the mixes could be defined as SCLC with good flowability, viscosity and passing ability. Hardened test results indicated that the addition of the fibers reduced the compressive strength and increased the tensile strength, flexural strength and fracture energy. Moreover, compared to monotype fibers, the hybrid ones formed effectively enhanced mechanical behaviors of SCLC. The mixes containing 0.75% GF and 0.25% BF was the optimum one and determined acceptable fresh and hardened properties as well as high temperature resistance.