Probability of Flexural Fatigue Failure of Concrete made with Recycled Concrete Aggregates

Abstract

The paper presents results of an investigation conducted to quantify the flexural fatigue performance of concrete in which the Coarse Natural Aggregates (NA) were systematically replaced with Coarse Recycled Concrete Aggregates (RCA). Concrete mix containing 100% NA was also tested for comparison purpose. The compressive strength results of 100% RCA showed maximum reduction followed by the concrete made with 50% RCA. The fatigue test data of concrete made with 50% and 100% RCA and 100% NA was obtained by conducting flexural fatigue tests on beam specimens of 100×100×500 mm size. The specimens were tested using 100 kN MTS Servo-controlled actuator under four-point flexural fatigue loads applied at frequency of 10 Hz. Static flexural tests were also conducted to facilitate fatigue testing. The maximum flexural strength of 5.10 MPa was observed by the concrete mix containing 0% RCA (100% NA) followed by 4.89 MPa and 4.53 MPa for 50% RCA and 100% RCA respectively. To predict the flexural fatigue strength of concrete made with RCA, the materials coefficients of fatigue strength prediction models have been obtained. The S-N-Pf models for three concrete mixes have also been generated from the fatigue test data analytically. Two-Million cycles fatigue strength has also been estimated which was coming out to be 50% and 56% of the actual flexural strength for concrete mixes containing 50% and 100% RCA respectively.