低温季节混凝土浇筑仓温度双控指标拟定及预警研究

Study on Drafting and Pre-warning of Double-control Index for Concrete Pouring Surface Temperature in Cold Seasons

低温季节浇筑混凝土,如果混凝土浇筑仓最高温度较低,将使早龄期混凝土力学性能发展较慢,对混凝土的早期抗裂不利。结合西南某建设中的混凝土特高拱坝低温季节浇筑仓实测温度,首先获得浇筑仓最高温度低于合适最高温度的概率,然后假设典型龄期的温度和温度变化率小于典型龄期的容许温度和容许温度变化率的概率与浇筑仓最高温度低于合适最高温度的概率相同,采用概率法拟定了混凝土浇筑仓温度双控指标,即混凝土浇筑仓达到最高温度前典型龄期对应的容许温度和容许温度变化率,以预警和控制混凝土浇筑仓出现最高温度过低的现象。

If the maximum temperature of concrete pouring surface is lower in cold seasons, the mechanics parameter of early age concrete will develop slowly, which is harmful to the early anti-cracking of concrete. Based on the measured temperatures of concrete pouting surface in the construction of an extra-high arch dam in southwest China in cold season, the probability of the maximum temperature of concrete pouring surface lower than the proper maximum temperature is firstly obtained, and then it is supposed that the probabilities of the temperature and temperature gradient lower than the allowable temperature and its gradient in typical age respectively are same with the probability of the maximum temperature of concrete pouring surface lower than the proper maximum temperature. Finally, the temperature double-control index, i.e. the allowable temperature and its gradient before the contract pouting surface reaching its maximum temperature in typical age, are put forward by probability method to warn and control the phenomenon of too low maximum temperature.