热带岛礁珊瑚骨料混凝土的耐久性及提升方法

Durability and improvement method of coral aggregate concrete on tropical reefs

为探究热带岛礁环境下珊瑚骨料混凝土的耐久性研究现状,提升其耐久性能。本文采用试验与理论分析相结合的方法,研究了珊瑚骨料混凝土的抗氯离子扩散性能、抗渗透性能以及抗碳化性能指标。结果表明:珊瑚骨料混凝土的表面自由氯离子含量以及表观氯离子扩散系数等耐久性指标远高于普通骨料混凝土以及再生骨料混凝土;相同水压作用下,珊瑚骨料混凝土的渗水高度比再生骨料混凝土、普通骨料混凝土以及轻骨料混凝土高5倍以上,表明珊瑚骨料混凝土的抗渗透性能明显劣于再生骨料混凝土、普通骨料混凝土和轻骨料混凝土;相同暴露时间下,珊瑚骨料混凝土的抗碳化性能优于普通骨料混凝土、轻骨料混凝土。为确保长期服役条件下珊瑚骨料混凝土具有较好的抗碳化性能,建议采用改善珊瑚骨料密实度、添加外加剂、降低水灰比以及掺入矿物掺合料等方法。

To explore the durability research status of coral aggregate concrete(CAC)in the tropical island environment and improve its durability,the chloride ion diffusion resistance,impermeability,and carbonation resistance of CAC were examined by the method combining experiments and theoretical analyses.The results show the durability indicators,such as surface free chloride ion content,and apparent chloride diffusion coefficient of CAC,are much higher than those of ordinary aggregate concrete(OAC)and recycled aggregate concrete(RAC).The water seepage height of CAC is more than five times higher than that of RAC,OAC,and lightweight aggregate concrete(LAC),indicating that the impermea-bility of CAC is significantly inferior to those of RAC,OAC,and LAC.Under the same exposure time,the carbonation resistance of CAC is better than those of OAC and LAC.To ensure that CAC has good carbonization resistance under long-term service conditions,it is recommended to improve its durability by improving the compactness of coral aggre-gate,adding admixtures,reducing the water-cement ratio and incorporating mineral admixtures.