矿物掺合料调控界面过渡区微结构对混凝土力学性能的影响

发布时间：2018-06-16 06:53

本文选题：界面过渡区 + 力学性能　；参考：《硅酸盐学报》2017年05期

【摘要】：系统测试了利用石灰石粉、矿粉及不同集料体积掺量、粒径分布配制试件的抗压强度与动弹模量,采用压汞法对相应试件孔径分布特征进行对比分析,研究掺合料对基体及界面过渡区(ITZ)孔结构的作用,分析掺合料调控ITZ微结构对混凝土力学性能的影响机理。结果表明:掺加5%石灰石粉可细化样品孔结构,使总孔隙率及10 nm以上孔的含量有所降低;掺加10%石灰石粉则会提高总孔隙率和10~100 nm孔体积,但降低100 nm以上孔的含量;掺加35%矿粉虽然减少了试件的总孔隙率及10 nm以上孔的含量,但会提高10 nm以下孔的体积;在大掺量矿粉时(70%),大于10 nm的毛细孔有所减少,而小于10 nm的微孔含量显著增加;掺加5%石灰石粉或35%矿粉,试件56 d抗压强度、动弹模量略有增加,且增加幅度随集料体积掺量增加或集料平均粒径的减小而增大;混凝土力学性能的改善主要取决于100 nm以上区间即界面过渡区孔结构的优化。
[Abstract]:The compressive strength and dynamic elastic modulus of the specimens prepared with limestone powder, mineral powder and different aggregate volume distribution and particle size distribution were systematically tested. The pore size distribution characteristics of the corresponding specimens were compared and analyzed by mercury injection method. The effect of admixtures on matrix and interfacial transition zone (ITZ) pore structure was studied, and the mechanism of the influence of the admixtures on the mechanical properties of concrete was analyzed. The results show that the pore structure of the sample can be refined by adding 5% limestone powder, the total porosity and the content of the pore above 10 nm can be decreased, the total porosity and the volume of 100 nm pore can be increased by adding 10% limestone powder, but the content of the pore above 100 nm can be decreased. The addition of 35% ore powder can decrease the total porosity of the sample and increase the volume of the pore below 10 nm, but increase the volume of the pore below 10 nm, and increase the content of micropore less than 10 nm in the large amount of mineral powder, the capillary pore is larger than 10 nm, and the pore volume is less than 10 nm. With the addition of 5% limestone or 35% mineral powder, the compressive strength and dynamic modulus of the specimens increased slightly in 56 days, and the increasing amplitude increased with the increase of the volume content of aggregate or the decrease of average particle size of aggregate. The improvement of the mechanical properties of concrete mainly depends on the optimization of the pore structure in the transition zone of the interface over 100 nm.
【作者单位】：同济大学材料科学与工程学院;东南大学材料科学与工程学院;Faculty
【基金】：国家自然科学基金项目(51608382,51378390,51402216)
【分类号】：TU528

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