微米和纳米Al2O3对水泥基材料力学与耐久性的影响

Effects of Micron-Al2O3 and Nano-Al2O3 on Mechanical Properties andDurability of Cement-based Material

为了明确微米和纳米Al2O3对水泥基材料力学性能与耐久性的改性作用,采用细度分别为1μm和10 nm的Al2O3替代水泥,制备低水胶比水泥基材料。通过宏观和微观测试手段,分析微米和纳米Al2O3对水泥基材料力学性能与耐久性的影响规律,并探析其作用机理。试验表明:掺量为0.5%~4.0%的微米Al2O3和纳米Al2O3能增强水泥基材料的力学性能,降低其干燥收缩;0.5%~2.0%微米Al2O3和0.5%~4.0%纳米Al2O3能降低水泥基材料的渗透系数,但4.0%微米Al2O3会增大水泥基材料的渗透系数。相对而言,纳米Al2O3对水泥基材料的改性作用优于微米Al2O3。电镜扫描和文献研究结果发现,纳米Al2O3和微米Al2O3在水泥基材料水化、硬化过程中发挥尺寸效应、填充效应和表面活性效应,进而达到增强水泥基材料的力学性能和耐久性的目的。研究成果为水泥基材料的改性提供试验基础。

By replacing cement with Al2O3 of 1μm and 10 nm,respectively,cement-based materials with low water-binder ratio were prepared for researching the modification effect of micron-Al 2O3 and nano-Al 2O3 on the mechanical properties and durability of cement-based material.Macro-and-microscopic approaches were adopted to examine the change law of mechanical performance and durability and to analyze the modification mechanism.Results demonstrated that both micron-Al 2 O 3 and nano-Al 2O3 at a dosage of 0.5%-4.0%could enhance the mechanical performance while reducing the drying shrinkage of cement-based material.Micron-Al 2O3 at a dosage of 0.5%-2.0%or nano-Al 2O3 at a dosage of 0.5%-4.0%could reduce the permeability coefficient;however,a 4.0%micron-Al2O 3 would increase the permeability coefficient.The modification effect of nano-Al2O3 is superior to that of micron-Al 2O3.SEM result and previous research findings prove that in the process of cement-based material’s hydration and hardening,micron-Al2O3 and nano-Al2O3 ameliorate the mechanical performance and durability through size effect,filling effect and surface activity effect.