EXPERIMENTAL INVESTIGATION OF LOW TO HIGH-STRENGTH STEEL FIBER REINFORCED LIGHTWEIGHT CONCRETE UNDER PURE TORSION

Results of an experimental investigation carried out to assess the effect of various concrete strength levels on behavior of steel fiber reinforced lightweight concrete (SFRLWC) under pure torsion are reported. The variables of the testing program were: compressive strength of concrete, volume of steel fibers, and the aspect ratio of steel fibers. The concrete strengths investigated are 9, 12, 30 and 61 MPa. Fiber content ranges from zero to 3.0 percent by volume of matrix. Addition of approximately two percent of fibers led to maximum torsional strength and toughness enhancement of SFRLWC; however, the improvement in higher strength concrete was more pronounced than that in lower strength concrete. In general, the torsion strength gained was higher for high strength level specimens with higher percentages of fiber volume and larger fiber aspect ratio. A proposed torsional strength formulation provided good agreement with the test results.