拌合工艺对煤矸石细骨料混凝土流动性和力学强度的影响  

Effect of Mixing Method on Fluidity and Mechanical Strength of Coal Gangue Fine Aggregate Concrete

作　　者：陈凤阁[1] 刘鑫 张亚鹏[2] 冯胜雷 孟文清[2] 崔邯龙[2] 郭秋硕 CHEN Fengge;LIU Xin;ZHANG Yapeng;FENG Shenglei;MENG Wenqing;CUI Hanlong;GUO Qiushuo(China Coal Handan Design Engineering Co.,Ltd.,Handan 056031,China;School of Civil Engineering,Hebei University of Engineering,Handan 056038,China)

机构地区：[1]中煤邯郸设计工程有限责任公司,河北邯郸056031 [2]河北工程大学土木工程学院,河北邯郸056038

出　　处：《金属矿山》2023年第9期263-268,共6页Metal Mine

基　　金：邯郸市科学技术开发项目(编号:21422111281,21422091238,214422053007);河北省自然科学基金项目(编号:E2022402050)。

摘　　要：洗选煤矸石具有杂质多、孔隙率大和吸水性强的特点,由其制备的混凝土流动性差、强度低。为解决上述问题,对洗选煤矸石细骨料混凝土的拌合工艺开展优化试验研究。首先对洗选煤矸石细骨料进行预湿处理,然后通过一次投料法来拌合混凝土,研究附加水量和预湿时间对混凝土拌合物流动性及硬化后强度的影响,最后利用扫描电镜观察预湿处理工艺对混凝土微观形貌的影响,并借助Image J软件对微观图像进行灰度分析。结果表明:随着附加水量的增加,混凝土拌合物的坍落度呈现上升的趋势,7 d和28 d抗压强度均随之增加;煤矸石细骨料预湿时间越长,拌合物坍落度越大,7 d和28 d抗压强度先增大后减小。预湿处理可以促进生成更多的C—S—H凝胶,改善混凝土的微孔结构,提高密实度。洗选煤矸石细骨料按饱和吸水率的100%加入附加水,预湿60 min后拌合的混凝土,可获得较好的坍落度和较高的抗压强度。研究成果有望为洗选煤矸石混凝土的商业化应用提供理论指导和技术支撑。Washing coal gangue has the characteristics of many impurities,large porosity and strong water absorption,and the concrete prepared from it has poor fluidity and low strength.In order to solve this problem,the mixing method of washing coal gangue was studied by optimization tests.Firstly,the washing coal gangue fine aggregate was pre-wetting,and then the con-crete was mixed by one feeding method.The effect of additional water amount and pre-wetting time on the fluidity and strength of concrete was studied.Finally,scanning electron microscope was used to observe the influence of pre-wetting method on the micromorphology of concrete,and the gray level of the micromorphology was analyzed by Image J.The results showed that with the increase of additional water,the slump of concrete mixture presents an upward trend,and the 7 d and 28 d compressive strength increases with it.The longer the pre-wetting time of coal gangue fine aggregate,the greater the slump of the mixture,and the 7 d and 28 d compressive strength first increased and then decreased.The pre-wetting treatment can promote the forma-tion of more C—S—H gels,improve the microporous structure of concrete,and increase the compactness.Better slump and higher compressive strength can be obtained by adding additional water to the washing coal gangue fine aggregate at 100%of saturated water absorption rate and mixing concrete after 60 minutes of prewetting.The research results are expected to provide theoretical guidance and technical support for the commercial application of washing gangue concrete.

关 键 词：洗选煤矸石 拌合工艺 附加水 预湿时间 坍落度 抗压强度 

分 类 号：TU528[建筑科学—建筑技术科学]