纤维素醚对砂浆塑性自由收缩的影响.pdf

免wx第15卷第5期
建筑材料学报
Vol 15, No 5
2012年10月
JOURNAL OF BUIIDING MATERIALS
文章编号:1007-9629(2012)05-0674-04
纤维素醚对砂浆塑性自由收缩的影响
刘斯风,王培铭,徐勇
(同济大学先进土木工程材料教育部重点实验室,上海201804)
摘要:采用非接触式激光位移传感器连续測试加速条件下甲基羟丙基纤维素醚(HPMC)改性水泥
砂浆的塑性自由收缩,并同时观测其失水率,分别建立了HPMC掺蚤与塑性自由收编、失水率回归
模型.结果表明:水泥砂浆塑性自由收缩随HPMC掺量的増加呈线性递减,掺0.1%~0.4%(质量
分数)的 HPMC可以减少水泥砂浆30%~50%的塑性自由收缩;随着HPMC掺量的増加,水泥砂
浆的失水率亦呈线性递减,掺0.1%~0.4%的HPMC可以降低水泥砂浆9%~29%的失水率;
HPMC掺量与自由收缩、砂浆失水率均呈明显的线性关系,HPMC减少水泥砂浆塑性自由收缩的
原因源于其优异的保水作用
关键词:甲基羟丙基纤维素醚(HPMC);砂浆;塑性自由收縮;失水率;回归模型
中图分类号:TU528.01
文献标志码:A
doi:10.3969/j.iss.1007-9629.2012.05.018
Effect of Cellulose Ether on Plastic Free Shrinkage of Mortar
LIU Si-feng, WANG Pei-ming, XU Yong
(Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, Tongji University
Abstract The plastic free shrinkage of the mortar modified by hydroxypropylmethyl cellulose(HPMC) under ac
celerating drying condition were determined by laser sensors equipped with digital computer systems. The water
loss of the mortar slab was weighed, and regression model of relationship between the use level of HPMC and
plastic free shrinkage, the use level of HPMC and loss of water in mortar, The results indicate that the plastic free
shrinkage of mortar linearly decreases with increasing HPMC content. Compared with normal cement mortar, the
plastic free shrinkage of the mortar modified by HPMC of 0. 1-0.4%(by mass)is reduced by 30-50%. The
water loss rate linearly reduces with increasing HPMC content, the water loss rate reaches about 9%-29% for the
mortar with 0. 1%0-0.A% HPMC. The fitting results show that both frcc shrinkage and loss of water change line-
arly with the use level of HPMC. Therefore, the reason of HPMC addition to reduce plastic free shrinkage of the
mortar is good water retaining property of HPMC.
Key words: hydroxypropylmethyl cellulose (HPMC); mortar; plastic free shrinkage; rate of water loss
regression model
与水泥混凝土相比,水泥砂浆更易开裂.除了原剂2別、掺入纤维等方法加以解决
材料本身的因素影响外,外界温度和湿度的变化会
作为商品水泥砂浆常用的聚合物外加剂一一一纤
使水泥砂浆快速失水,导致其加速开裂,对于水泥砂维素醚是由植物纤维素与烧碱反应、再经迷化后得
浆开裂问题,通常采用加强早期养护、使用膨胀到的纤维素衍生物?.詹镇峰等研究表明,釬维素
收稿目期:2011-06-03;修订日期:2011-07-13
基金项目:教育部新教师基金资助项目(20090072120007):同济大学先进土木工程材料教育部重点实验室开放基金资助项目(20]0105);
污染控制与资源化研究国家重点实验室开放课题资助项目( PCRRF11009)
第一作者:刘斯风(1970--),女,湖北江陵人,同济大学副教授,博十.FE-mail: isf(@ longji,edu,cn