국내 시멘트 및 콘크리트의 염화물 함유량 현황 분석 및 관련 기준 개선 제언

초록

In this study, both domestic and international specifications regarding allowable chloride content in reinforced concrete (RC) structures were analyzed, with the aim of improving the relevant domestic standards. Theoretical simulations of initial chloride contents in various concrete mixtures were also performed, based on domestic specifications. Furthermore, the chloride contents in mortar and concrete with Portland cement produced by six major manufacturers were evaluated. The control of chloride content in ready-mix concrete was investigated through statistical analysis involving two concrete production companies. Regarding the chloride contents in mortar samples measured via the ion electrode method, results ranging from 0.1530 kg/m3 to 0.2710 kg/m3 were obtained. These levels were considered relatively low, especially given that the cement mass used comprised up to 2/3 of the total mortar mass. For concrete, the results were assessed based on five specified design strength grades, and it was evident that mixtures with higher design strength exhibited greater chloride content due to the increased use of cement. In addition, it is worth noting that the measured chloride contents exhibited a variation ranging from 20 % to 30 % when different measuring devices were employed. Through the statistical analysis of chloride control in domestic ready-mixed concrete, a relatively high return rate was observed for concrete within the 35~40 MPa grade range. This was attributed to irregularly high chloride content in the cement and sea sand used in the concrete mix.

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