Based on the mechanism of alkali silica reaction( ASR), the effective alkali was defined as the part of alkali that had diffused into the reactive aggregate and participated in the chemical reaction. Using glass aggregate as reactive aggregate, the influence of curing temperature, reactive aggregate size and reactive aggregate addition(by mass) on the effective alkali content(by mass) in single reactive aggregate particle was studied. Based on the Fick's first law and Fick's second law, a calculation method for effective alkali concentration was proposed. The results show that the effective alkali content is influenced by curing temperature obviously. However, the influence of reactive aggregate size on effective alkali content is not remarkable. Besides, the effective alkali content decreases with the increase of reactive aggregate addition. The proposed calculation method for effective alkali concentration can be used to evaluate the effect of curing temperature, reactive aggregate size and addition effectively.%从碱硅酸反应(ASR)的化学本质出发,将有效碱进一步定义为扩散进入活性集料内并与活性SiO2发生化学反应的液相碱.在此基础上,以熔融石英玻璃为活性集料,研究养护温度、活性集料粒径和活性集料掺量(质量分数)对单颗活性集料内有效碱含量(质量分数)的影响;结合Fick第一定律和第二定律,建立了有效碱浓度的计算模型,结果表明:养护温度对单颗活性集料内有效碱含量影响显著;活性集料粒径对单颗活性集料内有效碱含量无显著影响;随着活性集料掺量的增加,单颗活性集料内有效碱含量呈现出一定的下降趋势;所建立的有效碱浓度计算模型可以有效反映养护温度、活性集料粒径和活性集料掺量对其的影响,对后续建模工作有一定的参考价值.
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