高性能轻集料混凝土在氯盐环境中的耐久性预测

Prediction of Durability of High Performance Lightweight Aggregate Concrete in Saline Environment

通过测试在海水中静置3年的高性能轻集料混凝土的Cl-分布,计算其Cl-扩散系数De并预测其使用寿命。研究结果证明,扩散系数De随胶结料用量和轻集料最大粒径增加而有所增加,部分轻砂被天然河砂取代后,De基本不变,采用膨胀粘土集料混凝土的De比采用烧结粉煤灰轻集料低得多。掺入硅灰可大幅度降低De。混凝土的电阻随De的降低而大幅度提高。掺硅灰的高性能轻集料混凝土在氯盐环境中的耐久性很好,使用寿命可达数十年至上百年。

The chloride diffusivity Dc and service life of high performance lightweight aggregate concrete （HPLWAC） in saline environment can be calculated through analyzing its chloride profile after immersing those specimens in seawater for 3 years. The test results show that the chloride diffusivity coefficient Dc in- creases as the binder content and maximum aggregate size increase. Part of light sand replaced by natural sand does not affect chloride diffusivity Dc . Diffusivity coefficient De using expanded clay as coarse aggregate is higher than that using sintering fly ash as coarse aggregate. Incorporation of silica fume is the most efficient means to reduce the chloride diffusivity Dc . The electrical resistivity of the concrete increases as the chloride diffusivity De increase. The durability of HPLWAC except for that without silica fume in saline environment is good.