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本文以复掺硫铝酸钙-氧化钙类膨胀剂和粉煤灰的混凝土为研究对象,通过测试限制膨胀率、限制强度、碳化深度,研究不同养护温度对混凝土抗碳化性能的影响规律。研究结果表明:在20℃、40℃、60℃三种养护温度下,对于限制膨胀率均满足要求的混凝土(膨胀剂掺量5%),适当的高温养护能提高抗碳化性能,过高的温度会使孔隙率和大孔数量增多,反而不利于抗碳化,表现为40℃养护时碳化深度最小,60℃次之,20℃最大。过高的温度同样不利于后期强度发展,表现为28d强度60℃养护时低于40℃。这与压汞实验的分析结果相一致。所以,补偿收缩混凝土内部温升不宜过高,最好控制在40℃以下。
In this paper, the concrete doped with calcium sulphoaluminate-calcium oxide expansive agent and fly ash was taken as the research object. The influence of different curing temperature on the carbonation resistance of concrete was studied by testing the limiting expansion rate, limiting strength and carbonation depth. The results show that proper curing at high temperature can improve the carbonation resistance of concrete (the content of expanders is 5%) under the three curing temperatures of 20 ℃, 40 ℃ and 60 ℃, The temperature will increase the porosity and the number of macropores, but not conducive to anti-carbonation, the performance of 40 ℃ when curing the smallest depth of carbonization, followed by 60 ℃, 20 ℃ maximum. Excessive temperature is also not conducive to the development of late strength, manifested as 28d intensity 60 ℃ conservation less than 40 ℃. This is consistent with the results of mercury intrusion experiments. Therefore, the shrinkage compensation concrete interior temperature should not be too high, the best control at 40 ℃ below.