Corrosion resistance of steel fibres in concrete under marine exposure

Abstract

This is the final paper of a series (1, 2, 3) which have reported different aspects of a long term study on the marine durability of steel fibre reinforced concrete (sfrc). Two mixes, one with and one without pfa were reinforced with three types of steel fibres. The cement content of the mixes was 430 and 590 kg/m 3 respectively. Prism specimens of these mixes were cured under marine exposure, both in the laboratory and at Aberdeen beach, for up to 2000 wet-dry cycles (1200 days). The state of corrosion of the steel fibres was investigated visually and by electrochemical analysis of fibres exposed at fractured surfaces of specimens after flexural testing. The results show that the generally accepted activation level of 0.4% Cl − by weight of cement does not apply to sfrc. Similarly, the threshold value of 0.61 for the ( Cl −) ( OH −) ratio, as proposed by Hausemann for initiation of corrosion, is not valid to steel fibre reinforced concrete. No corrosic of fibres embedded in concrete was evident at Cl − and ( Cl −) ( OH −) levels greatly exceeding the above values.