FLEXURAL FATIGUE BEHAVIOUR OF STEEL FIBRE REINFORCED CONCRETE WITH MIXED ASPECT RATIOS

Abstract

The expansion of infrastructural facilities has led to the use of structures such as marine structures, various types of bridges, machine foundations, industrial floors etc., which are subjected to repeated loads and vibratory loads. Hence the concrete is required to perform better than earlier in static and dynamic fatigue load applications. Fibre reinforced concrete is found effective to overcome the effect of repeated and vibratory loads. Various types of fibres differing in shape and size, aspect ratio and material properties may be used. In this thesis the flexural fatigue behaviour of SFRC using Xerox type corrugated steel fibres with two aspect ratios (20 & 40) has been studied, using various mixing percentages. The total fibre content was kept at 0.5%,1.0% and 1.5% by volume. The test result data corresponding to 28 days compressive strength, static flexural strength and flexural fatigue-life are presented in tables and graphs. For 28 days compressive strength, the volume fraction of 1% with mixed aspect ratios of 100 % AR-20 and 0 % AR 40 gives best results having a maximum increase of 43.28 % w.r.t. control mix. But for the flexural fatigue loading, the volume fraction of 1 % with mixed aspect ratios 75 % AR-20 and 25 % AR-40 gives the best results in terms of maximum number of load cycles taken by the specimens prior to failure.