Flexural fatigue strength prediction of self compacting concrete made with recycled concrete aggregates and blended cements

Abstract

The paper presents the findings of an investigation conducted to examine the flexural fatigue strength of Self Compacting Concrete (SCC) containing 50% Coarse Recycled Concrete Aggregates (RCA) and blended cements i.e. Silica Fume (SF) and Metakaolin (MK). Fatigue life data of different SCC mixes has been obtained by performing flexure fatigue tests on 224 beams of size 100 mm × 100 mm × 500 mm under four-point loading at varying stress levels ranging from 0.95 to 0.65 depending upon the mix. Tests data thus obtained has been utilized to represent the S-N relationships for different SCC mixes and has also been employed to evaluate the experimental coefficients of different strength prediction models. Concept of failure probability has been introduced into the fatigue life data of different SCC mixes and families of S-N-Pf curves have been generated to relate stress level, fatigue life and failure probability. Theoretical fatigue life and endurance limit/two million cycle fatigue strength have also been determined for different SCC mixes and found to show a degradation with the addition of RCA. However, addition of SF and MK has been found to significantly increase the endurance limit and theoretical fatigue life for blended SCC mixes containing RCA.