冻结井外壁高强混凝土的早期强度增长规律研究

Early-Stage Strength Growth of High-Strength Concrete in Outer Freezing Shaft Walls

针对冻结井外壁特殊的早期养护环境,开展了外壁混凝土早期强度增长规律的实验室及现场试验研究.结果表明:受大体积混凝土水化热的影响,外壁混凝土的早期强度增长迅速,1,3,7 d强度分别超过了配制强度的40%,70%,90%.外壁混凝土的早期强度增长速度明显超过标准养护试块,且越接近井壁厚度中央,混凝土的强度越高;龄期越短,上述差异越显著(尤其是3 d内).外壁采用现浇高强混凝土结构,其安全能够得到保障.

The early-stage strength growth of concrete in outer freezing shaft wall was studied by laboratory and field experiment. The results show that the strength growth at early stages proceeds rapidly due to heat of hydration in the mass of concrete. The strength measured at one, three or seven days exceeded the strength of the test article by 40, 70 and 90 percent, respectively. Strength growth in the outer shaft wall significantly exceeds the rate of strength growth in the standard test block. At short times, the closer the sample is to the center of the wall, the higher the strength compared to the test sample. This effect is most noticeable within three days after pouring. The safety of the outer shaft wall can be guaranteed if high-strength cast-in-place concrete is used.