Back-calculation Procedure for Cyclic Flexural Fracture Tests in Fiber Reinforced Concrete

摘要

Crack resistance of cement-based materials under flexural stresses was studied experimentally in order to back-calculate the tensile properties. Monotonic and cyclic tests were performed on plain and fiber-reinforced concrete materials. A methodology based on the R-Curve approach is proposed that implements the measurement of an effective crack length by the correlation of apparent compliance of specimens through loading and unloading cycles. Closed-loop three-point bending tests were conducted on notched beam specimens with crack mouth opening displacement (CMOD) as the controlling signal. The tests and the associated analyses were applied to several cases to evaluate the effects of curing time (strength development) as well as fiber-reinforcement (using AR-glass fibers) on the fracture behavior of concrete. The results showed that the fracture-based back-calculation method is relatively similar and comparable to predicted tensile stress-strain responses of other well-known methods.