正负温交变环境对低热水泥性能的影响

在大体积混凝土工程中,低热水泥因其低水化热和高后期强度的特性而受到广泛关注和应用。考虑到西部高原地区复杂的环境服役条件,该研究选取低热水泥与普通水泥作为对比样本,系统分析正负温交变环境对水泥砂浆强度发展、孔隙结构演变和微观形貌的影响。结果表明:正负温度交变环境会导致水泥砂浆的抗压强度降低。然而,低热水泥砂浆在强度表现上相较于普通水泥砂浆展现出优越性:在水中养护条件下,低热水泥砂浆的强度较普通水泥砂浆高出5%,在正负温度交变环境中高出4%,表明低热水泥对正负温度变化的耐受性更强。微观结构分析进一步证实了低热水泥在孔结构方面的优越性。低热水泥的孔隙率、平均孔径和最可几孔径均低于普通水泥,这表明其结构更为致密,从而在正负温度交变环境下具有更好的耐久性。尽管正负温度交变环境会在两种水泥中引起孔隙裂缝的增大,但低热水泥显示出更强的耐受力。该研究的发现为低热水泥在极端气候条件下的应用提供了科学依据,尤其是在西部高原等环境复杂的地区,低热水泥因其出色的性能而展现出广泛的应用潜力。

Low heat cement has received widespread attention and application in large volume concrete engineering due to its low hydration heat and high post strength characteristics.Considering the complex environmental service conditions in the western plateau region,this study selected low heat cement and ordinary portland cement as comparative samples to systematically analyze the influence of positive and negative temperature alternating environments on the strength development,pore structure evolution,and microstructure of cement mortar.The results indicate that the alternating environment of positive and negative temperatures can lead to a decrease in the compressive strength of cement mortar.However,low heat cement mortar shows superiority in strength performance compared to ordinary portland cement mortar:under water curing conditions,the strength of low heat cement mortar is 5%higher than that of ordinary portland cement mortar,and 4%higher in positive and negative temperature alternating environments,indicating that low heat cement has stronger tolerance to positive and negative temperature changes.The microstructure analysis further confirms the superiority of low heat cement in terms of pore structure.The porosity,average pore size,and most probable pore size of low heat cement are all lower than those of ordinary portland cement,indicating that its structure is denser and therefore has better durability in positive and negative temperature alternating environments.Although the alternating environment of positive and negative temperatures can cause an increase in pore cracks in both types of cement,low heat cement exhibits stronger resistance.The findings of this study provide scientific basis for the application of low heat cement under extreme climate conditions,especially in complex environmental areas such as the western plateau.Low heat cement has shown extensive application potential due to its excellent performance.