察尔汗盐湖腐蚀混凝土的长龄期损伤劣化规律

Long-Term Damage and Deterioration Law of Concrete under Corrosive Environment in Qarhan Salt Lake

摘要:

针对青海察尔汗盐湖盐渍土地区混凝土的腐蚀问题，通过测定暴露8 a后高性能混凝土（HPC）的动弹性模量和抗压强度，研究了相对动弹性模量、抗压腐蚀系数与28 d抗拉强度之间的相互关系，并结合水胶比、矿渣掺量对于HPC抗盐卤性能进行了二元相关性分析，最后分析了碳化深度和28 d抗压强度之间的相关性。结果表明：在盐卤环境中，HPC抗腐蚀性能随着28 d抗压强度的降低而减弱；HPC发生腐蚀破坏的相对动弹性模量临界值是0.80，并不是传统理论认为的0.60；水胶比低于0.33、矿渣掺量超过26%、且碳化深度控制在20 mm以下均能保证HPC较高的抗盐卤腐蚀能力。

Abstract:

Aiming at the corrosion problem of concrete in saline soil area of Qarhan Salt Lake in Qinghai， by measuring the dynamic elastic modulus and compressive strength of high performance concrete（HPC） exposed for 8 years， the relationship between relative dynamic elastic modulus， compressive corrosion coefficient and 28 d compressive strength was studied， and the binary correlation analysis of HPC’s brine resistance was made by combining water-binder ratio and slag content. Finally， the correlation between carbonation depth and 28 d compressive strength was analyzed. The results show that the corrosion resistance of HPC decreases with the decrease of 28 d compressive strength in brine environments. The critical value of relative dynamic elastic modulus for HPC corrosion damage is 0.80， contrary to the traditional theoretical threshold of 0.60. When the water-binder ratio is lower than 0.33， the slag content is more than 26%， and the carbonation depth is controlled below 20 mm， HPC achieves high brine corrosion resistance.