engleski

Fatigue behaviour of steel fibres reinforced concrete elements

Steel fibres can be used as reinforcement in concrete elements to enhance their post cracking flexural behaviour. The inclusion of fibres can also benefit the fatigue performance of concrete elements. This paper presents a study on the fatigue flexural strength of steel fibre reinforced concrete elements containing 0.5% volume fraction of fibres with hooked ends, 35 mm long and 0.55 mm in diameter. An experimental programme was conducted to obtain fatigue lives of SFRC elements at various stress levels. Twenty four prism specimens of size 150 mm x 150 mm x 600 mm were tested under four point flexural fatigue loading. Six static flexural tests were conducted prior to fatigue test to obtain static LOP (limit of proportionality) load. The load obtained from the static test was multiplied by 4 different stress levels (0.3, 0.5, 0.7 and 0.9) to calculate the load for the fatigue test. Load was applied following a sinusoidal wave pattern, at a frequency of 15 Hz until specimen failed or until it reached the maximum number of 2 million cycles. The results are presented as S – N relationship, with fatigue stress expressed as a percentage of the strength under static load and number of loading cycles to failure. Maximum and minimum displacements versus number of cycles for each specimen during testing are also presented. Fatigue strength of SFRC elements was compared to plain concrete elements.

fatigue, steel fibres, fibre reinforced concrete, experimental research

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