早强型聚羧酸减水剂对水下灌注桩性能的影响研究  

Study on Influence of Early Strength Polycarboxylic Acid Superplasticizer on Performance of Underwater Cast-in Pile

作　　者：王君峰 WANG Jun-feng(Heibei Branch of South to North Water Transfer Middle Line Project ConstructionAdministration, Shijiazhuang 050000, China)

机构地区：[1]南北水调中线干线工程建设管理局河北分局,石家庄05000

出　　处：《黑龙江水利科技》2021年第7期43-45,49,共4页Heilongjiang Hydraulic Science and Technology

摘　　要：水下灌注桩要求混凝土具有良好的和易性能,成型过程中不出现断桩等质量问题,龄期强度达标。早强型聚羧酸减水剂在混凝土硬化期间促进整体水化反应,达到增加早期强度的目的。优质粉煤灰由于具有球形颗粒,对于改善混凝土和易性,降低整体黏度,具有重要作用。重新开展水下灌注桩混凝土配合比设计工作,优化原材料比例,通过现场制备验证的方式,确定影响水下灌注桩基本性能、力学性能的影响因素。结果表明:当粉煤灰掺量为20%时,混凝土流动性能、黏聚性能最佳;混凝土倒筒时间达到3.2s,初始扩展度达到635mm,1h扩展度达到640mm,2h扩展度达到630mm,混凝土2h流动性能未损失,施工性能正常;当早强型减水剂掺量为4.0%时,混凝土早期抗压强度最优。Good workability of concrete is needed by underwater cast-in-place pile requires,no quality problems such as broken piles occur during the process of molding,and the age strength reaches the standard.The early strength polycarboxylic acid superplasticizer promotes the overall hydration reaction during the hardening of concrete and achieves the purpose of increasing the early strength.Due to its spherical particles,high quality fly ash plays an important role in improving the workability of concrete and reducing the overall viscosity.The concrete mix ratio design of underwater cast-in-place pile was carried out again,the proportion of raw materials was optimized,and the factors affecting the basic mechanical properties of underwater cast-in-place pile were determined by the way of on-site preparation and verification.The results show that when the fly ash content is 20%,the flow property and cohesive property of concrete are the best.The concrete inverted drum time reaches 3.2s,the initial expansion degree reaches 635mm,and the expansion degree reaches 640mm when 1hour,reaching 630mm when 2 hours,the flowing performance of concrete is not lost when 2 hours,the construction performance is normal.The early compressive strength of concrete is the best when the content of early strength water reducer is 4.0%.

关 键 词：水下灌注桩混凝土 粉煤灰 强度 配合比设计 早强型减水剂 

分 类 号：U655.55[交通运输工程—港口、海岸及近海工程]