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混凝土因在低温环境下具有优越的力学性能和耐久性,已被应用于液化天然气储藏塔外部保护层或内部接触层。但混凝土在低温环境下的热变形是一个复杂的过程。基于以前研究者所得水泥基材料超低温热形变宏观结果,采用差示扫描量热技术研究不同水灰比水饱和硬化水泥石中孔溶液的冰点,以解释热形变机理。结果表明:直径小于8 nm的孔中溶液的结冰对水泥基材料低温膨胀起主导作用;当环境最低温度低于–50℃时,水泥基材料热应变的变化和损失随水灰比增大逐渐明显。
Due to its superior mechanical properties and durability at low temperatures, concrete has been used in external protective layers or internal contact layers of liquefied natural gas storage tanks. However, the thermal deformation of concrete at low temperature is a complicated process. Based on the macroscopic results of ultra-low temperature thermal deformation of cement-based materials obtained by previous researchers, differential scanning calorimetry (DSC) was used to study the freezing point of pore solution in different water-cement ratio water-saturated hardened cement stones to explain the thermal deformation mechanism. The results show that the freezing of solution in the pores with diameter less than 8 nm plays a dominant role in the low temperature expansion of cement-based materials. When the minimum ambient temperature is lower than -50 ℃, the thermal strain of cement-based materials changes with the increase of water-cement ratio Gradually obvious.