Fu Chao, Xie Chunyan, Liu Jing, Wei Xiuli, Wu Dake
College of Engineering and Technology, Southwest University, Chongqing 400715, China.
Chongqing Academy of Agricultural Sciences, Chongqing 401329, China.
Materials (Basel). 2020 Feb 13;13(4):857. doi: 10.3390/ma13040857.
The application of nano-materials to modify construction materials has become a research hotspot in recent years, but often different scholars use different research methods and reach different conclusions about the same material, which is not conducive to the performance comparison between different materials. In this paper, nano-SiO, carbon nanotubes (CNTs) and nanocrystalline cellulose (NCC) were used as raw materials to prepare cement-based composites to compare the effects of the three nanomaterials on the mechanical and water absorption properties under the same experimental conditions, and their principles were investigated via The scanning electron microscope (SEM), X-Ray Diffraction (XRD) and other microscopic analysis testing methods. At the same time, strength benefit indexes are introduced to comprehensively evaluate the economics of the strength improvement provided by the three kinds of nanomaterial. The results show that doping with nano-SiO, CNTs and NCC can promote the hydration process of cement effectively. The composite material exhibits excellent mechanical properties at the macro level because of the nucleation and filling effect of nano-SiO, and the bridging and strengthening effects of CNTs and NCC. The compressive strength increased by 45.13%, 28.31% and 44.19% at 7d, and 23.09%, 18.40% and 23.40% at 28d. The flexural strength of 7d increased by 31.00%, 36.22 and 54.81%, and 14.91%, 22.23% and 30.46% at 28d. The water absorption is SiO < NCC < CNTs, and the nano-SiO is lower than the other two materials at least 15.54%. CNTs group has the lowest compressive strength benefit, which is 16.91 yuan/m, and the lowest flexural strength benefit is NCC, which is 3.59 yuan/m.
近年来，纳米材料在建筑材料改性中的应用已成为研究热点，但不同学者往往采用不同的研究方法，对同一材料得出不同结论，这不利于不同材料之间的性能比较。本文以纳米二氧化硅（nano-SiO₂）、碳纳米管（CNTs）和纳米晶纤维素（NCC）为原料制备水泥基复合材料，在相同实验条件下比较这三种纳米材料对力学性能和吸水性能的影响，并通过扫描电子显微镜（SEM）、X射线衍射（XRD）等微观分析测试方法探究其作用原理。同时，引入强度效益指标来综合评价这三种纳米材料增强强度的经济性。结果表明，掺入纳米二氧化硅、碳纳米管和纳米晶纤维素能有效促进水泥的水化过程。由于纳米二氧化硅的成核和填充作用，以及碳纳米管和纳米晶纤维素的桥接和增强作用，复合材料在宏观层面表现出优异的力学性能。7d抗压强度分别提高了45.13%、28.31%和44.19%，28d分别提高了23.09%、18.40%和23.40%。7d抗折强度分别提高了31.00%、36.22%和54.81%，28d分别提高了14.91%、22.23%和30.46%。吸水率为SiO₂＜NCC＜CNTs，纳米二氧化硅的吸水率比其他两种材料至少低15.54%。碳纳米管组的抗压强度效益最低，为16.91元/m³，抗折强度效益最低的是纳米晶纤维素，为3.59元/m³。
