萘系高效减水剂对砂浆早期变形性能影响的研究  

Influence of polynaphthalene sulphonate superplasticizer on early deformation of mortars

作　　者：王信刚[1] 梁文泉[2] 马保国[1] 李相国[1] 何真[2] 叶群山[2] 

机构地区：[1]武汉理工大学硅酸盐材料工程教育部重点实验室,湖北武汉430070 [2]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

出　　处：《混凝土》2004年第11期28-30,44,共4页Concrete

基　　金：国家重点基础研究发展规划"973计划"资助项目(编号:2001CB610704-3)

摘　　要：　高效减水剂是高性能水泥基材料不可缺少的组分,早期收缩开裂是导致水泥基材料劣化的根本原因。本文采用多通道椭圆环收缩开裂测试手段、自由收缩和强度试验综合评价了萘系高效减水剂对水泥砂浆早期收缩开裂和强度的影响。结果表明,掺萘系高效减水剂延长了砂浆初始开裂时间,从而降低了砂浆的开裂敏感性,且高浓型比普通型更能有效地降低砂浆开裂敏感性。掺萘系高效减水剂增大了砂浆自由收缩值,砂浆自由收缩值都随着UNF掺量的增大而增大,且在同等掺量条件下,掺高浓型UNF砂浆的自由收缩值要比掺普通型UNF的略大。在干燥养护条件下,普通型UNF比高浓型UNF更能有效地提高砂浆的28d强度。High range water-reducing agent is an indispensable ingredient in high performance cement-based materials.Initial cracking dues to shrinkage accelerates obviously the deteriorations of cement-based materials.The general effect of Polynaphthalene Sulphonate Superplasticizer (PNS) on shrinkage cracking of mortars has been investigated by means of multi-channel ellipse ring shrinkage cracking test,free shrinkage and strength under drying conditions.The results show that PNS has improved initial cracking time of mortars and has decreased cracking sensitivity.As for decreasing cracking sensitivity,high thickness type PNS is more effective than common thickness type PNS.The effect of PNS is to increase free shrinkage of mortars when keeping the constant W/B ratio and the content of cement pastes.Furthermore,free shrinkage of mortars with high thickness type PNS is slightly higher than those with common thickness type PNS.High thickness type PNS is more effective to improve flexural and compressive strength of mortars at 28 days than common thickness type PNS under drying conditions.

关 键 词：萘系高效减水剂 砂浆 开裂敏感性 自由收缩 变形性能 早期收缩 高性能水泥基材料 组分 降低 干燥 

分 类 号：TU528[建筑科学—建筑技术科学] TU375