海洋环境下预除氯海水拌制钢筋混凝土构件可行性

Feasibility of pre-dechlorinated seawater mixed reinforced concrete specimens in marine environment

考虑岛礁建设中拌和混凝土的需要,本文提出采用工业污水除氯中常用的超高石灰铝法对模拟海水进行预除氯。探讨了除氯反应所需较优反应物料比例、较优反应时间及反应温度和二次除氯对除氯效果的影响;采用预除氯海水拌和混凝土试件,评估了混凝土的抗氯离子渗透性能、力学性能和预除氯混凝土中普通钢筋的抗腐蚀性能。结果表明:与模拟海水拌和的混凝土试件相比,预除氯海水在环境条件下的前期对混凝土的抗氯离子渗透性能有一定改善;降低水胶比可有效提高混凝土的抗氯离子渗透性能;在模拟海洋干湿循环下、预除氯海水混凝土试件中,普通钢筋在干湿循环的前4个周期表现出较优的抗腐蚀性能。因此,在海洋环境中采用超高石灰铝法对海水进行预除氯并用于浇筑钢筋混凝土构件是可行的。

Considering the need for concrete mixing in island and reef construction,the ultra-high lime with alumina process,UHLA,commonly used to remove chlorine from industrial wastewater,was proposed to reduce chloride ion content in simulated seawater.The study initially determined the optimal proportion of reaction materials and the optimal reaction time and assessed the effects of reaction temperature and secondary dechlorination on dechlorination efficiency.Subsequently,the chloride ion penetration resistance and mechanical properties of the concrete mixed with pre-dechlorinated seawater as well as the corrosion resistance of ordinary steel bars in this type of the concrete were evaluated.Test results revealed that,compared to concrete specimens mixed with untreated simulated seawater,using pre-dechlorinated seawater enhanced the chloride ion penetration resistance of the concrete,especially in the early stages of environmental exposure.Moreover,this resistance was significantly improved with a lower water-binder ratio.Under simulated marine environmental conditions,the reinforcing bars in concrete mixed with pre-dechlorinated seawater exhibited strong corrosion resistance during the first 5 drying-wetting cycles.These findings confirm that employing the UHLA process to predechlorinate seawater is a viable method for producing reinforced concrete members suitable for marine environments.