摘要
为了探究煤系纳米偏高岭土(CNMK)对碱骨料反应的抑制作用,采用快速砂浆棒试验方法测量CNMK质量分数为1%、3%、5%、10%、15%时砂浆棒在不同浸泡时间下的膨胀率,利用超声波检测仪获得砂浆棒的相对动弹性模量,通过扫描电镜和能谱分析法从微观层次分析CNMK对碱骨料反应的作用机制.结果表明,CNMK可延迟砂浆棒表面裂缝的出现及扩展.随浸泡时间的增加,CNMK对水泥砂浆内部碱骨料反应的抑制作用逐渐减弱.浸泡时间为7和52 d时,CNMK质量分数为15%的砂浆棒膨胀率较普通砂浆棒分别降低78.06%和53.72%.CNMK砂浆棒的相对动弹性模量随浸泡龄期的变化小于普通砂浆棒.CNMK细化了水泥基体内部孔结构,使碱骨料反应区更加密实,导致砂浆棒内部钠与硅的原子数比值下降,从而有效抑制了砂浆棒内部碱骨料反应.
To investigate the inhibition effect of coal nano-metakaolin(CNMK)on the alkali-aggregate reaction,the expansion rates of the mortar bars with the CNMK mass fraction of 1%,3%,5%,10%,and 15%at different soaking ages were measured by the rapid mortar bar test method.The relative dynamic elasticity modulus of the mortar bars was obtained by an ultrasonic detector.Scanning electron microscopy and energy spectrum analysis measurements were conducted to analyze the action mechanism of CNMK on alkali-aggregate reaction at the micro-level.The results show that CNMK can delay the crack generation and propagation of the mortar bars.The inhibition effects of CNMK on alkali-aggregate reaction gradually weaken with the increase of the soaking age.The expansion rate of the mortar bars with the CNMK mass fraction of 15%decreased by 78.06%and 53.72%at 7 and 52 d compared with ordinary mortar bars,respectively.The change in the relative dynamic elastic modulus of the CNMK mortar bars with the change of the soaking age is smaller than that of the ordinary mortar bars.CNMK refines the pore structure of cement matrix,makes the zone of alkali-aggregate reaction more denser,leads to a decrease in the atomic amounts ratio of sodium and silicon in the mortar bar,and effectively inhibits the alkali-aggregate reaction of the mortar bars.
作者
李秋超
范颖芳
祁妍紫
张贵波
Li Qiuchao;Fan Yingfang;Qi Yanzi;Zhang Guibo(Department of Civil Engineering,Dalian Maritime University,Dalian 116026,China)
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2023年第3期455-462,共8页
Journal of Southeast University：Natural Science Edition
基金
国家自然科学基金资助项目(51578099).
关键词
煤系纳米偏高岭土
碱骨料反应
砂浆棒
膨胀率
相对动弹性模量
coal nano-metakaolin
alkali-aggregate reaction
mortar bar
expansion rate
relative dynamic elasticity modulus
