减水剂对高保坍UHPC150性能影响的室内试验研究及应用  

Laboratory experimental study and application of water reducing agent on performance of high slump retention UHPC150

作　　者：栾宏 逯春平 梁远博[1] LUAN Hong;LU Chun-ping;LIANG Yuan-bo(CCCC Shanghai Third Harbour Engineering Science and Technology Research Institute Co.,Ltd.,Shanghai 200032,China;The Eighth Engineering(Hunan)Co.,Ltd.of CCCC Third Harbor Engineering Co.,Ltd.,Zhuzhou,Hunan 412007,China)

机构地区：[1]中交上海三航科学研究院有限公司,上海200032 [2]中交三航局第八工程(湖南)有限公司,湖南株洲412007

出　　处：《中国港湾建设》2024年第6期45-49,77,共6页China Harbour Engineering

摘　　要：超高性能混凝土(UHPC)因其超高韧性和耐久性得到了越来越多的应用,但UHPC的拌合需要专用搅拌设备,在应用中存在其搅拌地与浇筑地相距较远的情况,需要UHPC具有高保坍效果。为配制高保坍UHPC,采用标准型、缓凝型2种聚羧酸高性能减水剂,研究了其掺量对UHPC的凝结时间、工作性(保坍效果)、匀质性和强度的影响。结果表明:随着减水剂掺量的增加,2种减水剂拌制的UHPC凝结时间均有所增大,保坍效果也有所增强,但UHPC黏度值、早期强度均有所下降。与标准型减水剂相比,缓凝型减水剂虽然可以显著延长UHPC的凝结时间,但拌制的UHPC初始坍落扩展度较小、保坍效果较差。清水塘大桥高保坍UHPC采用标准型减水剂配制,减水剂掺量为0.8%,拌制的UHPC出机0~5 h内的坍落扩展度在650~750 mm之间、黏度值在2700~3200 mPa·s之间,泵送性能和保坍效果优异,匀质性好,有效避免了钢纤维沉降,且1 d强度达35 MPa以上,工程应用效果良好。Ultra-high performance concrete(UHPC)has been increasingly applied due to its ultra-high toughness and durability.However,the mixing of UHPC requires specialized mixing equipment.In the application,the mixing ground is far away from the pouring ground,which requires UHPC to have a high slump retention effect.For the preparation of high slump retention UHPC,two kinds of high performance polycarboxylic acid water reducing agents,named standard type and retarding type,were used to study the effects of their dosage on the setting time,workability(slump retention effect),homogeneity and strength of UHPC.The results show that:With the increase of water reducing agent content,the setting time of UHPC mixed with two kinds of water reducing agents increased,and the slump retention effect also increased,but the viscosity value and early strength of UHPC decreased.Compared with standard water reducing agent,retarding type water reducing agent can significantly prolong the setting time of UHPC,but the initial slump expansion of mixed UHPC is smaller and the slump retention effect is poor.Qingshuitang Bridge high slump retention UHPC is prepared with standard water reducing agent,the content of water reducing agent is 0.8%,the slump expansion degree of mixed UHPC is between 650~750 mm and the viscosity value is between 2700~3200 mPa·s within 0~5 h after pouring out of the machine,the pumping performance and slump retention effect are excellent,with good homogeneity,effectively avoiding steel fiber settlement,and the 1-day strength reaches above 35 MPa.The engineering application effect is good.

关 键 词：高保坍UHPC 凝结时间 匀质性 早期强度 

分 类 号：U654[交通运输工程—港口、海岸及近海工程] TU528[交通运输工程—船舶与海洋工程]