Effect of anti-washout admixtures in underwater concrete

Abstract

The present paper describes the results of experimental research on the effect of anti-washout admixtures on concrete properties, conducted at the Intemac Central Laboratory for the author?s (*) PhD thesis. According to these findings, acceptable effectiveness calls for a cement dose on the order of 400 kg/m3 and an admixture content of at least 2% by cement weight. These conditions guarantee concrete compressive strength of at least 20 to 25 MPa, even in the event of moderate concrete contact with the water during placement. One particularly relevant result was the drop observed in the concrete-steel bond, which may necessitate anchorage and lapping lengths substantially longer than specified in the EHE Code, depending on bar diameter, or the substitution of mechanical anchorage for bonded anchorage or lapping.