内河库水位变动下码头桩基混凝土碳化深度预测模型

内河环境下,由于混凝土碳化所导致的内部钢筋锈蚀是引起港口码头结构发生耐久性失效破坏的主要原因。为研究内河库水位周期性变动下码头桩基混凝土的碳化规律,开展一般大气环境与干湿交替环境下混凝土的加速碳化物理试验。结果表明:1)混凝土碳化深度随碳化时间的增加而逐渐增加,碳化速率随碳化龄期增长而减缓。2)与一般大气环境相比,干湿交替作用下混凝土的碳化深度更小。基于Fick第一定律的碳化深度模型,通过拟合回归并修正后建立了内河一般大气环境和干湿交替环境下码头桩基混凝土碳化深度预测模型。经对比,模型预测值与试验实测值吻合程度良好,验证了该模型的精度。研究成果可为内河港口码头基础结构运营维护及耐久性评估提供技术支撑。

Prediction model of carbonation depth of wharf pile foundation concrete under fluctuation of inland river reservoir water level

Under an inland river environment, the corrosion of internal steel bars due to concrete carbonization is the primary cause for the durability failure of the port structure. To study the carbonation law of wharf pile foundation concrete under the effect of periodic fluctuation of water level in the inland reservoir,the accelerated carbonation test of concrete in general atmospheric environment and alternate dry-wet environment was carried out. Test results indicate that: 1) The carbonization depth of concrete gradually increases with the increase of the carbonization time,and the carbonization rate slows down as the carbonization age increases. 2) Compared with the atmospheric environment,carbonation depth of concrete under the alternating action of a dry-wet cycle is smaller. Based on the carbonation depth model derived from Fick’ s first law,through fitting and correction,a prediction model of concrete carbonation depth under an inland service environment is established and verified.Results show good consistency between the proposed model values and the tested values,which verifies the accuracy of the model. The research achievement can provide technical support for the operation,maintenance,and durability evaluation of the inland port terminal infrastructure.