溶蚀条件下水化硅酸钙结构演化与粉煤灰适宜掺量研究  

Structure evolution of calcium silicate hydrate and suitable content of fly ash among cementitious materials under dissolution

作　　者：蔡新华[1] 何真[1] 孙海燕[1] 范福平[2] 

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072 [2]中国水电顾问集团贵阳勘测设计研究院,贵州贵阳550081

出　　处：《水利学报》2012年第3期302-307,共6页Journal of Hydraulic Engineering

基　　金：国家自然科学基金(50972109);教育部博士点专项基金(20090141110021);国家重点基础研究发展计划(2009CB623201)

摘　　要：利用魔角旋转核磁共振(29Si MAS-NMR)测试技术从机理上分析了不同掺量粉煤灰(30%～70%)对水泥基材料强度发展和溶蚀条件下性能退化的影响规律。结果表明:随着粉煤灰掺量的增加,水泥硬化浆体强度逐渐下降,但掺量为50%时,强度下降率最小,超过这个掺量强度下降率增大;与此对应,水化硅酸钙(C-S-H)中Q1和Q2含量相应减少,特别是Q1的变化令人关注。粉煤灰掺量从0增加到50%时,Q0,Q1,Q2信号峰强度均较溶蚀前下降,但Q1信号峰下降幅度更大;当粉煤灰掺量为70%时,Q1信号峰已不明显,Q2也相应减少,此时引起强度降低和溶蚀后性能退化显著。溶蚀后Q(21Al)信号峰强度增大,粉煤灰掺量50%时最为明显。研究表明,Q1具有很强的工程特性,其变化对粉煤灰适宜掺量的确定起着关键作用。Cement pastes incorporated with fly ash（30%～70%） with and without dissolution were investigated employing 29Si MAS NMR（magic angle spinning nuclear magnetic resonance） technique.The mechanism of strength development with different fly ash content and property deterioration with dissolution was discussed.The results reveal that,the compressive strength of specimens decrease with the increase of fly ash content,and the descent ratio is the least when the content of fly ash is 50%.Accordingly,the intensity of Q1 and Q2 decreased with the increase of the content fly ash,and the attention of invesligation was captured by the change of Q1.The intensity of Q0,Q1 and Q2 decreased after dissolution when the content of fly ash was 0-50%,but Q1 did faster.The peak of Q1 was not distinct and the area under Q2 was lower than other series when the fly ash content was 70%.Correspondingly,the descent ratio of strength and property deterioration was significant.The intensity of Q2（1Al） increased obviously,especially with 50% fly ash.These results indicate that Q1 plays an important role of determining the suitable content of fly ash in cementitious materials,because it has a visible engineering property.

关 键 词：粉煤灰 适宜掺量 溶蚀 核磁共振 水化硅酸钙 

分 类 号：TU502[建筑科学—建筑技术科学]