河南省鸡湾水库工程骨料碱活性研究

Experimental Research on Aggregate Alkali Reactivity of Jiwan Reservoir Project in Henan Province

【目的】骨料质量的优劣直接关系到混凝土的耐久性和工程的安全运行,本研究采用多种方法检验骨料的碱活性,为准确判定骨料的碱活性提供依据,为工程建设提供技术支撑。【方法】通过岩相法、砂浆棒快速法和碳酸盐小岩石柱法对河南鸡湾水库工程骨料碱活性进行试验。【结果】岩相法检测结果表明,鸡湾水库工程拟选用骨料中含有一定量的碱活性组分,具有潜在的碱-骨料反应活性。砂浆棒快速法试验结果表明,11组骨料样品中4组块石骨料样品为非碱-硅酸反应活性骨料;5组样品为碱-硅酸反应活性骨料,工程应用中应对这些骨料应采取必要的抑制措施,以保证工程安全;2组骨料样品28 d砂浆膨胀率接近0.2%,且试件14 d后膨胀率发展速率未出现收敛状态,建议关注,工程应用中应采取相应的抑制措施。碳酸盐小岩石柱法试验结果表明,6组块石样品均为非碱-碳酸盐反应活性骨料。【结论】研究结果为准确判定鸡湾水库工程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。

[Purposes]The quality of aggregate is directly related to the durability of concrete and the safe operation of the project.This study uses a variety of methods to test aggregate alkali activity,so as to provide a basis for the accurate determination of aggregate alkali activity and provide technical support for the construction of the project.[Methods]In this study,the aggregate alkali activity in Jiwan Reservoir project of Henan Province was studied by petrographic analysis,accelerating mortar-bar method and small rock column method.[Findings]The results on aggregate alkali activity test of Jiwan Reservoir project in Henan province are introduced in detail.The results of petrographic analysis show that the selected aggregate of Jiwan Reservoir project contains a certain amount of alkali-active components,which has potential alkali-aggregate reaction activity.The results of Accelerating Mortar-bar Method showed that 4 of 11 groups of aggregate samples were non-alkali-silica reactive aggregate;5 of 12 groups of aggregate samples are active aggregate with potential harmful alkali-silica reaction,and necessary suppression measures should be taken to these aggregates in engineering application to ensure engineering safety.The mortar expansion ratio of the remaining two groups of aggregate samples was close to 0.2%at 28 days,and the expansion rate of the specimens did not converge after 14 days.Therefore,corresponding control measures should be taken in engineering application to ensure engineering safety.The test results of small rock column method showed that the 6 groups of block rock samples were non-alkalicarbonate active aggregates.[Conclusions]The research results can provide technical support for the accurate judgment of aggregate alkali reactivity,and thus benefit the project quality.