2017 Volume 71 Issue 1 Pages 109-116
Sulfate attack is known as one of the deterioration phenomena of concrete structures. In particular, delayed ettringite formation is considered a serious problem. According to previous researches, it has been pointed out that delayed ettringite formation is affected by the hydrates coexisting around monosulfate, however it has not been shown experimentally yet. The purpose of this research is to discuss that the effect of pretreatment drying of monosulfate and coexisting substances on ettringite formation. As a result, when a mixture of monosulfate and C-S-H was mixed and hydrated using an aqueous solution of Na2SO4, the amount of ettringite was increased. In particular, it was shown experimentally that the amount ettringite was greatly increased when coexisting the C-S-H with high C/S ratio. In addition, it has been shown for the first time that amount of the ettringite is further increased after hydration with an aqueous solution of Na2SO4 as a result of strongly pre-treatment drying of monosulfate and coexisting C-S-H. Therefore, it maybe suggested that the expansion due to sulfate attack was affected by coexisting of strongly dried C-S-H with high C/S ratio.
