低气压养护对水泥净浆性能的影响

Effect of Low Air Pressure Curing on Performance of Cement Paste

高原气候环境下基础设施结构混凝土材料强度、耐久性所面临的问题逐渐凸显,研究高原气候环境对混凝土性能的影响具有重要意义。通过低气压试验箱模拟95.0、70.7、57.6、47.0和38.7 kPa气压环境,测试了不同养护气压下水泥净浆的抗压强度、孔结构和物相组成。结果表明,在同一龄期时,随着养护气压的降低,水泥净浆的抗压强度逐渐降低,孔隙率逐渐增加,最可几孔径逐渐增大,过渡孔比例减小,毛细孔和大孔的比例增加,水化产物中的Ca(OH)_(2)逐渐减少。此外,本文还分析了水泥净浆抗压强度与孔结构的关系,基于水泥净浆孔结构参数,建立了水泥净浆抗压强度预测模型。

The problems of strength and durability of concrete materials for infrastructure structures in plateau climate are becoming more and more prominent.It is of great significance to study the influence of plateau climate environment on concrete properties.The low pressure test chamber was used to simulate the air pressure environment of 95.0,70.7,57.6,47.0 and 38.7 kPa,and the performance indicators such as compressive strength,pore structure and phase composition of cement paste under different curing air pressures were tested.The results show that at the same age,with the decrease of curing air pressure,the compressive strength of cement paste decreases and the porosity increases,the most probable pore diameter of the sample increases,the proportion of transition pore decreases,the proportion of capillary pore and macropore increases,and the Ca(OH)_(2) in the hydration products of cement paste decreases.In addition,the correlation between the compressive strength of cement paste and pore structure was analyzed,based on the pore structure parameters of cement paste,and the prediction model of compressive strength of cement paste was established.