高强轻骨料混凝土在海洋环境中耐久性探讨

HIGH-STRENGTH LIGHTWEIGHT CONCTETE AND IT'S DURABILITY IN SALINE ENVIRONMENT

叙述了高强轻骨料混凝土（５０～１００ＭＰａ）的配制及在海洋环境中氯离子扩散系数（Ｄｅ）和耐久性问题。实验结果表明，使用轻骨料，通过控制水灰比、掺入硅粉可以配制出强度５０～１００ＭＰａ、容重１５９４～１８６５ｋｇ／ｍ３的轻骨料高强混凝土。该混凝土的Ｄｅ很低，在２．７～５．６×１０－９ｃｍ２／ｓ之间。当钢筋外硅粉混凝土保护层为７５ｍｍ时，氯离子扩散使钢筋表面混凝土达到腐蚀临界浓度（０．４％）所需时间近百年，耐久性很好。掺硅灰（ＳｉｌｉｃａＦｕｍｅ）可使Ｄｅ降低４倍，因此海工建筑使用硅灰混凝土是解决耐久性问题的主要措施之一。

Studies on the availbility of production of high-strength lightweight concrete and the diffusivity of chlorides from natural seawater are presented. The test results show 50 ～100MPa high-strensth lightweight concrete can be produced with a density of less than 1865kg/m3 by the control of w/c and the incorporation of silica fume. The chloride diffusivity is very low,typically varying from 2. 7 to 5. 6×10-9cm2/s. With a cover thickness of 75mm,the time for the chloride to reach its shreshold value will last up to 100 years,thus a very good durability.It is the silica fume that lower the chloride diffusivity of concrete and make the concrete durablein saline enviornment.