早强抗拉剂在连续刚构箱梁中的应用研究  

Research on Application of Early Strength Agent in Box Girder Concrete of Continuous Rigid Frame

作　　者：李扬 陈金义 马骉 LI Yang;CHEN Jin-yi;MA Biao(Shanghai Municipal Engineering Design Institute(Group)Co.Ltd.,Shanghai 200092,China;Shanghai Municipal Engineering Design Institute Group 10th Design Institute Co.Ltd.,Lanzhou 730000,China)

机构地区：[1]上海市政工程设计研究总院(集团)有限公司,上海市200092 [2]上海市政工程设计研究总院集团第十市政设计院有限公司,兰州市730000

出　　处：《公路》2022年第10期150-155,共6页Highway

基　　金：国家自然科学基金项目,项目编号51878488;甘肃省科技计划资助项目,项目编号19YF3GA004。

摘　　要：从混凝土材料的角度,对某大跨径预应力混凝土连续刚构桥箱梁施工期间的开裂问题展开研究。在统计裂缝情况和归纳开裂原因的基础上,对箱梁混凝土的早期强度发展规律以及早强抗拉剂的应用效果进行了试验。结果表明:混凝土中掺入的粉煤灰与水泥浆之间存在较多薄弱界面,可导致早期抗拉强度降低;养护温度偏低对早期抗拉强度也有明显的负面作用;而早强抗拉剂的掺入可极大促进水化进程,在水化早期生成大量Aft(钙矾石),从而提高混凝土早期强度。经过实桥应用验证,早强抗拉剂对箱梁混凝土早期裂缝可以起到显著的预防效果。From the view of concrete material,a research on box girder cracking issue of a long-span prestressed concrete continuous rigid frame bridge is conducted.Based on the statistics of cracks and the induction of cracking reasons,the early strength development of girder concrete and the application effect of early strength agent are tested.The results show that there are many weak interfaces between fly ash and cement slurry,which can reduce the early tensile strength.Low curing temperature also has obvious negative effect on early tensile strength.Adding early strength agent can greatly promote the hydration process and generate a large amount of Aft at the beginning,thus improving the early strength of concrete.Through verification on a project practice,the early strength agent can play a significant role in preventing early cracks of box girder.

关 键 词：连续刚构箱梁 早强抗拉剂 混凝土开裂 应用研究 

分 类 号：U448.213[建筑科学—桥梁与隧道工程] TU375[交通运输工程—道路与铁道工程]