Numerical simulation investigation on hydration heat temperature and early cracking risk of concrete box girder in cold regions  

作　　者：Shi Han Yongjian Liu Yi Lyu Jiang Liu Ning Zhang 

机构地区：[1]School of Highway,Chang'an University,Xian 710064,China [2]Qinghai Transportation Engineering Technical Service Center,Xining 810008,China [3]School of Civil Engineering,Chongqing University,Chongqing 400045,China [4]College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China

出　　处：《Journal of Traffic and Transportation Engineering(English Edition)》2023年第4期697-720,共24页交通运输工程学报（英文版）

基　　金：funded by the Key R&D Plan of Qinghai Province(2023-SF-110);the National Natural Science Foundation of China(52108111);the Special Fund for Basic Scientific Research of Central College of Chang’an University(300102212102)。

摘　　要：The temperature change caused by hydration leads to early-age cracking in concrete box girder.The early-age cracking risk is further improved with low air temperature and large daily temperature difference,especially in Northwest China.To fill this gap,a temperature experiment and numerical simulation were performed on an actual concrete box girder segment in Northwest China.The temperature field,thermal stress and cracking risk were analyzed using evolution curves,distribution curves and contours.The key parameters that influence the hydration heat temperature,including the cement hydration heat release,cement content,height-width ratio of web,initial temperature,convective coefficient of top plate surface,were analyzed.An anti-cracking case based on parameters analysis was put forward.The results indicated that the temperature evolution can be divided into three stages:warming,cooling and environment significantly impacting.Along the thickness of each plate,temperature distributed is single peak in the center.Along the width or height,temperature distributed is double peaks at axillary position for the top and bottom plates,and single peak in center for the web.The axillary position and web have high thermal stress and significant cracking risks.The temperature difference of each plate,and the early-age cracking risk can be reduced by effectively adjusting the key parameters.Among these,the former two parameters are the most significant factors.The maximum cracking risk can be decreased by 15.7%for every 50 kJ/kg hydration heat reduction.The maximum cracking risk can be decreased by 13.1%for every 50 kg/m^(3)cement content reduction.

关 键 词：Bridge engineering Concrete boxgirder Hydration heat Cold region Temperature action Thermal stress 

分 类 号：U445.57[建筑科学—桥梁与隧道工程]