基于Arrhenius方程预测既有构件混凝土材料的潜在AAR安全性

Predicting the potential AAR risk of field concrete based on Arrhenius equation

针对具有潜在碱集料反应(AAR)影响的既有构件混凝土,探索了基于Arrhenius方程描述的反应动力学原理快速预测其AAR安全性的方法。以碱含量分别为2.99、3.89 kg/m^3两组混凝土为对象,综合混凝土材料组成与孔溶液碱度、芯样试体实验室快速膨胀数据拟合和Arrhenius模型寿命计算,结果表明:养护温度和养护液碱度对混凝土试体的膨胀具有明显的促进作用;根据高温、高碱条件下快速膨胀试验和拟合结果,可以获取混凝土在实际孔溶液碱度和常温条件下的膨胀速率常数和预期服役寿命;碱含量分别为2.99、3.89 kg/m^3的两组混凝土,其AAR风险预测结果有显著差别。建立混凝土AAR性能快速试验方法和优化基于AAR反应动力学的寿命预测模型是发展基于性能的混凝土AAR耐久性设计和评估的发展方向。

For predicting the potential alkali aggregate reaction （AAR） risk of field concrete,the accelerated method based on reaction kinetics described by Arrhenius equation was explored.For field concrete elements with alkali contents of 2.99 kg/m3 and 3.89 kg/m3 re- spectively, based on the concrete proportion, the alkalinity of concrete pore solution, the fitting results for the accelerated expansion on concrete cores, and life prediction model derived fiom Arrhenius equation, results indicate that the curing temperature and the alkalinity of curing solution can accelerate the expansion of concrete specimens significantly.Based on the accelerated expansion at high temperature and high alkalinity and the fitting results, the constant of expansion rate and service life at room temperature and normal alkalinity of con- crete pore solution can be obtained.The predicted service life of concretes with alkali contents of 2.99 kg/m3 and 3.89 kg/m3 show signifi- cant differences.Establishing the performance based accelerated AAR test method and optimizing the life prediction model based on the re- action kinetics of AAR are needed for developing performance based design and evaluation of AAR durable concrete.