基于混凝土骨料碱活性试验研究  

Experimental Study Based on Alkali Reactivity of Concrete Aggregate

作　　者：樊强[1] FAN Qiang(Xinjiang Water Resources and Hydropower Survey,Design and Research Institute CO.LTD.,Changji 831100,China)

机构地区：[1]新疆水利水电勘测设计研究院有限责任公司,新疆昌吉831100

出　　处：《河南水利与南水北调》2023年第7期109-110,共2页Henan Water Resources & South-to-North Water Diversion

摘　　要：对混凝土骨料中的碱活性矿物是否存在,进行了检测试验,通过采取岩相法与砂浆棒快速法来对合格的粗细骨料进行分析。结果表明:骨料母岩由粉晶微晶灰岩、弱蚀变沉凝灰岩以及碎裂巨晶灰岩等组成,骨料中均有碱活性矿物成分;通过观察水泥与骨料成型的砂浆棒28 d膨胀率,粗骨料的膨胀率为0.32%,比0.20%高,该细骨料的膨胀率为0.26%,比0.20%高,说明该粗骨料以及细骨料均是活性骨料;粗骨料与细骨料掺入15%粉煤灰之后,试件28 d的膨胀率分别为0.137%与0.127%,均比0.10%大,对于碱骨料反应不能有效地进行抑制。该组粗骨料与细骨料掺入20%粉煤灰之后,试件28 d的膨胀率分别为0.095%与0.077%,均比0.10%小,对于碱骨料反应能有效地进行抑制。该组粗骨料与细骨料掺入25%粉煤灰之后,试件28 d的膨胀率分别为0.046%与0.035%,均比0.10%小,对于碱骨料反应能有效地进行抑制。由此在粗骨料以及细骨料作为混凝土骨料时,建议掺入不低于20%的粉煤灰来对混凝土碱-骨料反应进行抑制。The existence of alkali-activated mineral in concrete aggregates is tested.The qualified coarse and fine aggregates are analyzed by using petrographic method and mortar bar rapid method.The results show the following three points.Firstly,the aggregate parent rock is composed of microcrystalline limestone,weakly altered sedimentary tuff and cataclastic megacrystalline limestone.There are alkali-activated mineral components in the aggregate.Secondly,by observing the 28-day expansion rate of the mortar bar formed by cement and aggregate,the expansion rate of the coarse aggregate is 0.32%,higher than 0.2%.The expansion rate of the fine aggregate is 0.26%,higher than 0.2%.These data indicating that the coarse aggregate and fine aggregate are both active aggregates.Thirdly,after adding 15%fly ash into the coarse aggregate and fine aggregate,the expansion rate of the specimen after 28 days is 0.137%and 0.127%,respectively.Both of them are higher than 0.1%,which can not effectively inhibit the alkali aggregate reaction.After adding 20%fly ash into the coarse aggregate and fine aggregate of this group,the expansion rate of the test piece after 28-day is 0.095%and 0.077%,respectively.Both of them are smaller than 0.1%,which can effectively inhibit the alkali aggregate reaction.After adding 25%fly ash into the coarse aggregate and fine aggregate of this group,the expansion rate of the test piece after 28-day is 0.046%and 0.035%,respectively.Both of them are smaller than 0.1%,which can effectively inhibit the alkali aggregate reaction.Therefore,when coarse aggregate and fine aggregate are used as concrete aggregate,it is recommended to add no less than 20%fly ash to inhibit the alkali-aggregate reaction of concrete.

关 键 词：混凝土 粗骨料 细骨料 岩相法 砂浆棒快速法 骨料碱活性 

分 类 号：TV41[水利工程—水工结构工程]