南极低温环境用混凝土的制备与性能

Preparation and properties of concrete under cryogenic circumstance in Antarctica

为使混凝土在-40~-20℃且有风影响的南极低温环境下具有良好的工作性能、力学性能和抗冻性能,同时尽量减少使用加热或保温等辅助措施,采用自研的胶凝材料和增强剂,设置了3种低温和3种成型养护条件,开展了室内和室外的混凝土性能研究,并对混凝土的断面形貌进行了观察。结果表明:在南极低温环境下,制备的混凝土工作性能、力学性能和抗冻性能均满足相关要求,可用于南极低温环境下的混凝土工程,但至少须在混凝土浇筑后1 d内采用加热或保温等辅助措施保证拆模前强度的增长,拆模后即可低温自然养护。低温可以抑制水泥的水化反应,且环境温度越低,抑制效果越明显;南极低温环境下混凝土的水化反应主要发生在成型后的7 d内,加强混凝土早期尤其是前7 d的质量控制是南极低温环境下混凝土工程的关键。

In order to make sure that concrete has good working performance,mechanical property and frost resistance at-40 to-20 C and with the influence of winds under cryogenic circumstance in Antarctic and,at the same time,minimize the use of heating or thermal insulation and other auxiliary measures,three low temperatures and three types of curing conditions that were set and researched on both indoor and outdoor concrete properties was carried out with self-developed cementitious materials and reinforcing agents,and the cross-sectional morphological features of concrete were also observed.The research results show that the working performance,mechanical properties and frost resistance of thus prepared concrete meet the relevant requirements under cryogenic circumstance in Antarctic and can be used in concrete projects in Antarctic,but the concrete must be heated or thermally insulated or protected with auxiliary measures within at least 1 day after pouring to ensure the strength growth before formwork removal and can be normally cured in low temperature after formwork removal.Low temperature can inhibit the hydration reaction of cement and the lower the ambient temperature is,the more obvious the inhibition effect will be.The hydration reaction of concrete under cryogenic circumstance in Antarctic occurs significantly within 7 days after concrete is poured and molded,hence,intensification of quality control of concrete in its early age,especially in the first 7 days,is the key to concrete construction under cryogenic circumstance in Antarctic.