摘要
本文对武穴长江公路大桥南边跨宽幅PK断面混凝土箱梁温控防裂技术进行研究。通过对高性能混凝土配合比优化设计与早期抗裂性、长期收缩变形性能及耐久性试验,提出大掺量粉煤灰与矿粉复合掺合料可有效降低大体积混凝土水化热温升;基于温度与温度应力仿真计算结果制定了温控标准,提出各种温控防裂措施并对其应用效果进行评价。同时针对箱梁空腔薄壁结构易在变截面部位出现应力集中而导致开裂问题进行探讨分析。工程实践表明,施工所采取配合比、温控措施有效防止了有害裂缝的产生。
In this paper,the temperature control and crack prevention technology of concrete box girder with wide PK section in the south side span of Wuxue Yangtze River Highway Bridge is studied.The optimum design of mix proportion,early crack resistance,long-term shrinkage and deformation performance and durability test are studied and analyzed.It is put forward that the hydration heat of mass concrete can be reduced by large amount of fly ash and mineral powder compound admixture.Based on the simulation calculation of temperature and thermal stress,the temperature control standard is established.Various temperature control and crack prevention measures are put foward and the application effect is evaluated.At the same time,the cracking problem of box gir-der thin-walled structure with cavity is studied and analyzed because of stress concentration at variable cross-section.Engineering practice shows that the proportioning and temperature control measures adopted in construction effectively prevent the occurrence of harmful cracks.
作者
李福友
LI Fuyou(China Railway Construction Bridge Engineering Bureau Group First Engineering Co.Ltd.,Dalian Liaoning 116033,China)
出处
《铁道建筑技术》
2020年第8期107-111,共5页
Railway Construction Technology
基金
中国铁建股份有限公司科技研究开发计划项目(18-A03)。
关键词
宽幅PK断面箱梁
高性能混凝土
配合比优化
温控措施
防裂措施
数值计算及监测
wide PK section box girder
high performance concrete
mix ratio optimization
temperature control measure
crack prevention measure
numerical calculation and monitoring
