Durability of steel fibre reinforced shotcrete with regard to corrosion

摘要

The paper describes results from ongoing exposure tests examining steel fibre corrosion in cracked shotcrete. The purpose of the work is to shed light on questions about the long term durability of steel fibres in cracked concrete. In field exposure tests beams with different composition and crack widths are exposed to three different environments. After 2.5 years of exposure there is a continued increase in residual strength noted for small crack widths. For larger crack widths the increase has stopped. Measurements of the chloride contents show higher levels than in an earlier evaluation and the content increases closer to the crack opening. The following conclusions can be drawn from the second evaluation: 1) Samples exposed to freeze-thaw salts show greater evidence of fibre corrosion, 2) An increased crack width leads to increased corrosion, 3) Longer fibres corrode more than short ones at the same crack width, 4) The amount of corrosion decreased with an increased depth from the crack opening.