碳酸盐岩骨料碱活性综合判定的试验研究

Experimental Research on the Comprehensive Judgment of Alkali Activity of Carbonate Aggregate

选用某水电工程8组碳酸盐岩骨料样品,首先采用X射线衍射试验、化学组成法和岩相法对骨料的碱活性进行预判,然后通过砂浆棒快速法、小岩石柱法和混凝土棱柱体法等测长试验方法对这8组骨料样品碱活性进行综合判定。X射线衍射试验结果表明,8组岩石样品主要由方解石和白云石组成,角砾岩中还含有少量石英和高岭石;化学组成法试验结果表明,5组灰岩骨料样品不具有潜在碱-碳酸盐反应活性,而3组角砾岩骨料样品的碱活性需结合其他方法进行判定;岩相分析试验结果表明,8组骨料中有4组骨料为非活性骨料,其余4组骨料的碱活性需结合其他方法进行判定;砂浆棒快速法结果表明,8组骨料样品均为非碱-硅酸反应活性骨料;小岩石柱法试验结果表明,8组骨料样品均为非碱-碳酸盐反应活性骨料;混凝土棱柱体法试验结果表明,8组骨料样品均为非活性骨料。通过以上试验方法的结果综合判定8组碳酸盐岩骨料样品为非活性骨料。

In this paper,choose a hydropower project 8 groups of carbonate aggregate samples,first by X-ray diffraction test,chemical composition and petrographic method for aggregate alkali activity,and then by accelerating mortar-bar method,small rock column method and concrete prism method for the 8 rock samples of aggregate alkali activity comprehensive judgement.X-ray diffraction test results show that the 8 rock samples are mainly composed of calcite and dolomite,breccia also contains a small amount of quartz and kaolinite.The results of chemical composition test showed that the 5 groups of limestone aggregate samples did not have potential alkalicarbonate reactivity,while the alkali activity of the 3 groups of breccia aggregate samples should be determined by other methods.The results of petrographic analysis showed that 4 of the 8 groups of aggregate were non-alkali active aggregate,and the alkali activity of the remaining 4 groups of aggregate should be determined by other methods.The results of accelerating mortar-bar method showed that all the 8 rock samples were non-alkali-silicicate reactive aggregate.The results of small rock column test showed that all the 8 rock samples were non-alkali-carbonate reactive aggregate.The experimental results of concrete prism method show that 8 groups of aggregate samples are inactive aggregate.Based on the test results of the above test methods,8 groups of carbonate aggregate are comprehensively determined to be inactive aggregate.