To study the carbonation problem of concrete box girder under different CO2 concentrations and reac-tion times,a set of concrete box girder model were made. The accelerated carbonation experiment was carried out with 4 kinds of working conditions composed by two kinds of concentration(10%,20%), and two phase of car-bonization time(14 d,28 d). The results show that the ratio of reaction rate of outer angle part and one-dimen-sional part is about 1.56,which was slightly higher than the theoretical value. By comparing the carbonization de-gree under different working conditions,it is concluded that when the concentration of CO2 increases from 10% to 20%, the carbonation depth growth rate is about 1.2. When the reaction time increases from 14 d to 28 d,the car-bonation depth growth rate is about 1.32. It is indicated that the effect of time on carbonization depth is greater than that of concentration in the accelerated carbonation experiment. With the increase of reaction time,each meas-uring point carbonation coefficient decreased,it's showed that the carbonation rate decreases with the advance of re-action. With the increase of CO2 concentration,the carbonation coefficient tends to be stable.%为研究混凝土箱梁在不同CO2浓度和反应时间作用下的碳化问题,制作了一组混凝土箱梁模型,将10%、20%两种浓度和14 d、28 d碳化时间组合出4种工况进行了快速碳化试验研究.结果表明,外角部的反应速率与一维碳化的速率比值约为1.56,略高于理论值.通过比较各工况下的碳化程度得出,当CO2浓度从10%增大20%时,碳化深度增长倍数约为1.2;反应时间从14 d增大到28 d时,碳化深度增长倍数约为1.32,表明在快速碳化试验中,时间对碳化深度的影响大于浓度的影响.随着反应时间的增加,各测点碳化系数均有所下降,表明碳化速率随着反应的进行而减小;随着CO2浓度的升高,碳化系数趋于稳定.
展开▼
