粉煤灰中不同CaO含量对水泥浆体安定性及抗裂性的影响研究

Study on the impact of different CaO contents in fly ash on the stability and crack resistance of cement paste

摘要

研究粉煤灰中不同的CaO含量对水泥浆体安定性及抗裂性的影响。选取4种CaO含量的粉煤灰，分别为3.42%、16.22%、10.35%及20.89%进行对比分析。结果显示：雷氏夹法安定性膨胀值随着CaO含量和掺量的增加略有增大，当4种粉煤灰在40%掺量范围内体积安定性良好；空气中28 d时，水泥砂浆都呈收缩状态，且都随着CaO含量的增加而收缩略有减小；水泥品种、粉煤灰掺量相同的条件下，CaO含量为20.89%的粉煤灰胶凝材料初始开裂时间比掺加其他3种粉煤灰短，掺加CaO含量为3.42%粉煤灰的胶凝材料初始开裂时间最长。

Abstract

The impact of varying CaO concentrations in fly ash on the stability and crack resistance of cement paste was studied. Four kinds of fly ash with CaO content of 3.42%, 16.22%, 10.35% and 20.89% were selected for comparative analysis. The findings reveal that, as the CaO content and its proportion in the mix increase, the stability expansion value measured by Ray's clip method exhibits a slight upward trend. Notably, all four fly ash varieties exhibit excellent volume stability within a 40% dosage range.Furthermore, after 28 days, it was observed that all cement mortars underwent shrinkage. However, interestingly, as the CaO content rose, the degree of shrinkage decreased marginally.When comparing cementitious materials with identical cement types and fly ash dosages, it was evident that the initial cracking time was significantly shorter for the fly ash containing 20.89% CaO compared to the other three types. Conversely, the cementitious material with 3.42% CaO content exhibited the longest initial cracking time.

关键词

高钙灰 / 氧化钙含量 / 安定性 / 抗裂性

Key words

high calcium ash / calcium oxide content / stability / crack resistance

基金资助

新疆水发建设集团科研项目(EQ098/ FY079)

新疆水发建设集团科研项目(QBT067/ FY28)