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冬期混凝土施工,对于掺用各种不同的外加剂,以前大多数的研究是放在冰箱里,以旬平均温度作为混凝土抗冻的设计温度;而对自然条件下养护的混凝土研究却很少。冬天的气温,一天之内的变化是很大的,混凝土强度在不断变化的温度下有着不同的发展。另外,混凝土本身在水泥凝结硬化过程中也不断放出热量,它补充着混凝土内部的温度。这与在冰箱里按恒定的温度作冷冻试验所得出的结果有一些差别。为了与实际施工条件一致,我们做了在自然条件下混凝土掺复合外加剂的试验,并应用于现场施工。
In winter concrete construction, most of the previous studies were carried out in refrigerators with the addition of various admixtures. The mean ten-day temperature was used as the antifreeze design temperature for concrete; however, there were few studies on concrete under natural conditions. The temperature in winter, the change in one day is very big, the concrete strength has different development under the changing temperature. In addition, the concrete itself continuously releases heat during the setting and hardening of the cement, which supplements the temperature inside the concrete. This is somewhat different from the results obtained by freezing the test in a refrigerator at a constant temperature. In order to be consistent with the actual construction conditions, we have done experiments on concrete mixed admixtures under natural conditions and applied them on site.