混凝土骨料碱活性综合判定的试验研究

Experimental research on the comprehensive judgment of concrete aggregate alkali reactivity

采用多种检测方法对某水电工程骨料碱活性进行了研究。岩相法检测结果表明,6个骨料样品中含有一定量的隐晶状石英和隐晶状玻璃质,这两种成分具有潜在的碱-硅酸反应活性。对于XJ-2骨料样品:砂浆棒快速法试验结果表明,该骨料为具有潜在碱-硅酸反应活性的骨料;混凝土棱柱体快速法和混凝土棱柱体法试验结果表明,该骨料属于后期膨胀较快的骨料。对于XJ-4骨料样品:混凝土棱柱体法试验结果表明,棱柱体试件一年膨胀率接近0.04%限值,且试件膨胀率仍继续发展,该骨料也属于后期膨胀较快的骨料,建议给予关注。研究结果为准确判定骨料的碱活性提供了技术支持,为保证工程质量奠定了基础。

Several test methods were adopted to study the alkali reactivity of six aggregate samples from a certain hydraulic project.The test results of petrography method indicated that a certain amount of cryptocrystalline quartz and cryptocrystalline glass was contained in all the six aggregate samples,and both of these two components were potentially alkali-reactive.For aggregate XJ-2,it was judged to be potentially alkali reactive in accelerating mortar bar tests,and showed a higher expansion rate in later stage in accelerating concrete prism tests and concrete prism tests.For aggregate XJ-4,its concrete prisms had an annual expansion ratio close to the limit value of 0.04%,and the expansion was also developing quickly in later stage,which deserved our attention.The research results can provide technical support for the accurate judgment of aggregate alkali reactivity,and thus benefit the project quality.test results of accelerating mortar bar method showed that the 28 d expansion ratio of mortar with aggregate XJ-2 was larger than the limit value of 0.2%,and aggregate XJ-2 should be potentially alkali reactive.