Analysis of Flexural Fatigue for Pavement Quality Concrete Containing Copper Slag as Replacement of River Sand

Abstract

An investigation was carried out to analyze the flexural fatigue performance of pavement quality concrete (PQC) of M40 and M50 grades, made with conventional materials out of which river sand (RS) was replaced by copper slag (CS) by varying concentrations to the extent of 100% by volume. Experiments were conducted in the laboratory to determine the 90-day flexural strength of PQC samples (100×100×500 mm) under four-point loading. Based on respective flexural strength, repeated loads were applied for the conduct of flexural fatigue tests of PQC specimens at stress levels of 0.7, 0.8, and 0.9, each at 1 Hz frequency. In terms of fatigue life distributions, the flexural fatigue performance of several PQC mixtures has been evaluated. Three methods were used to estimate various parameters for the Weibull distribution. It is observed that the fatigue life distribution of both M40 and M50 grade PQC mixes made with CS can be modeled by a two-parameter Weibull distribution with a correlation coefficient of more than 0.95. The estimation of fatigue life of PQC mixes has also been done at different failure probabilities. The 90-day flexural strength of PQC mixes (both grades) with CS replacing RS, increased compared with conventional PQC. Further, X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) images of PQC mixes confirmed the homogeneity of the concrete. The fatigue performance was also enhanced with CS replacing RS. The goodness-of-fit test also indicated that the present model is valid at the 5% significance level for PQC (both grades) made with CS.