摘要
对于干燥环境下的水利水电抗磨蚀混凝土而言,由于采用低水胶比,导致混凝土收缩开裂和脱空等耐久性问题极为突出,维护及修复费用耗资巨大。为此,结合某工程配合比设计试验项目,在中热水泥掺合粉煤灰、硅粉基础上,掺入聚丙烯纤维、聚羧酸减水剂和减缩剂对混凝土进行改性研究。结果表明:与萘系混凝土减水剂相比,采用聚羧酸减水剂混凝土干缩率降低13%,开裂宽度减少76%;掺入聚丙烯纤维开裂宽度减少65%;掺入减缩剂降低混凝土干缩率约30%左右,混凝土裂缝宽度减少34%。针对干燥环境下抗磨蚀混凝土干缩率较大的特点,配合比设计建议采用聚羧酸减水剂,同时双掺聚丙烯纤维和减缩剂的技术方案,以更好地解决抗磨蚀混凝土收缩、开裂和脱空等耐久性问题。
For the water conservancy and hydropower anti-abrasion concrete in dry environment,due to the low water-binder ratio,the durability problems such as concrete shrinkage cracking and void are very prominent,and the cost of maintenance and repair is huge.For this reason,combined with a mix design test project,and based on moderate heat cement mixed with fly ash and silica powder,polypropylene fiber,polycarboxylic acid water reducing agent and shrinkage reducing agentare added to modify the concrete.The results show that compared with naphthalene water reducer,for concrete with polycarboxylic acid water reducing agent,the dry shrinkage rate is reduced by 13%,and the crack width is reduced by 76%;for concrete with polypropylene fiber,the crack width is reduced by 65%;while for concrete with shrinkage reducing agent,the dry shrinkage rate is reduced by about 30%,and the crack width is reduced by 34%.In view of the characteristics of high dry shrinkage of anti-abrasion concrete in dry environment,it is suggested to adopt the technical scheme of polycarboxylic acid water reducing agent added with polypropylene fiber and shrinkage reducing agent for mix design,so as to better solve the durability problems such as shrinkage,cracking and void of anti-abrasion concrete.
作者
胡宏峡
HU Hongxia(Investigation,Design and Research of Sinohydro Engineering Bureau 4 Co.,Ltd.,Xining 810000,China)
出处
《人民珠江》
2020年第7期118-125,共8页
Pearl River
关键词
高性能抗磨蚀混凝土
干缩变形
开裂时间
开裂宽度
耐久性
配合比设计
high performance anti-abrasion concrete
dry shrinkage deformation
cracking time
crack width
durability
mix design
