粉煤灰掺量对氯氧镁水泥混凝土物理力学性能的影响  

Influence of Fly ash Content on Physical and Mechanical Properties of Magnesium Oxychloride Cement Concrete

作　　者：刘盼 常成功[1,2] 刘秀泉 董金美 郑卫新[1,2] 肖学英 文静[1,2] LIU Pan;CHANG Chenggong;LIU Xiuquan;DONG Jinmei;ZHENG Weixin;XIAO Xueying;WEN Jing(Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining 810008,China;Qinghai Provincial Key Laboratory of Resources and Chemistry of Salt Lakes,Xining 810008,China;University of Chinese Academy of Science,Beijing 100049,China)

机构地区：[1]中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,西宁810008 [2]青海省盐湖资源化学重点实验室,西宁810008 [3]中国科学院大学,北京100049

出　　处：《硅酸盐通报》2021年第5期1564-1572,共9页Bulletin of the Chinese Ceramic Society

基　　金：青海省重点研发与转化计划(2019-GX-165);青海省应用基础研究项目(2020-ZJ-746);中国科学院青年创新促进会(2018467,2019423)。

摘　　要：为了拓展氯氧镁水泥(MOC)材料的应用领域,以盐湖提钾肥副产物水氯镁石、轻烧氧化镁和粉煤灰为胶凝材料,制备了不同粉煤灰掺量的氯氧镁水泥混凝土(MOCC)。研究了粉煤灰掺量对MOCC抗压强度、物相组成、微观形貌和孔结构的影响。结果表明:随着粉煤灰掺量的增加,MOCC的抗压强度逐渐降低,当粉煤灰掺量为40%(质量分数)时,其300 d抗压强度降低至39.99 MPa,降低了22.52%。MOCC的主要水化产物为5Mg(OH)_(2)·MgCl_(2)·8H_(2)O(5·1·8)和Mg(OH)_(2),掺加粉煤灰并没有产生新的晶相。掺入粉煤灰增加了MOCC的孔隙率和有害孔体积,从而降低了其抗压强度。采用相同水灰比制备了普通硅酸盐水泥混凝土,抗压强度对比测试结果表明:掺40%的粉煤灰MOCC的抗压强度虽然比未掺粉煤灰MOCC抗压强度低,但仍比普通硅酸盐水泥混凝土300 d龄期的抗压强度(33.42 MPa)高出19.66%,说明MOCC比普通硅酸盐水泥混凝土具有较高的抗压强度。In order to expand the application fields of magnesium oxychloride cement(MOC)materials,magnesium oxychloride cement concrete(MOCC)with different fly ash content was prepared by using bischofite,light burned magnesia and fly ash as cementitious materials,in which bischofite is a by-product of potassium fertilizer extracted from salt lake.The influence of fly ash content on compressive strength,phase composition,micromorphology and pore structure of MOCC were studied.The results show that with the increase of fly ash content,the compressive strength of MOCC gradually decreases.When the content of fly ash is 40%(mass fraction),its 300 d compressive strength decreases to 39.99 MPa,which is a decrease of 22.52%.The main hydration products of MOCC are 5Mg(OH)_(2)·MgCl_(2)·8H_(2)O(5·1·8)and Mg(OH)_(2).The addition of fly ash does not produce a new crystal phase.The addition of fly ash increases the porosity and harmful pore volume of MOCC,thereby reducing its compressive strength.Ordinary Portland cement concrete was prepared with the same water-cement ratio.The comparative test results of compressive strength show that although the compressive strength of MOCC with 40% fly ash is lower than that of MOCC without fly ash,it is still 19.66% higher than that of ordinary Portland cement concrete at 300 d age,indicating that MOCC has higher compressive strength than that of ordinary Portland cement concrete.

关 键 词：水氯镁石 氯氧镁水泥混凝土 微观结构 粉煤灰 抗压强度 凝结时间 

分 类 号：TU528[建筑科学—建筑技术科学]