纳米级硅灰及碳管对水泥基材料减振性能的影响

Effect of Nanoscale Silica Fume and Carbon Nanotube on Damping Capacity of Cement-based Composite

将纳米级超细硅灰(USF)或/与多壁纳米碳管(MWCNT)引入水泥基体制备了3组纳米复合材料,并制备了参比试件(Plain/C)。先后采用自由衰减、半功率带宽法及三点弯曲法测试相应试件的阻尼系数(ζ)及抗折强度(σ),以评价USF或/与MWCNT对水泥基减振及力学性能的影响。结果表明:与Plain/C相比,USF的微填充及火山灰效应可显著提高基体的σ,但不利于ζ的提升;中空管状MWCNT的位错、黏滞效应可使复合材料具有良好的减振性能,但分散较差时,MWCNT易形成孔洞缺陷,不利于σ的提升;USF及MWCNT的结合很好地发挥各自优点,SEM显示相互能与基体形成良好的交联增强体系,相应ζ,σ的提高幅度分别达30.21%,24.13%。

Nanoscale Ultrafine Silica Fume （USF） or/and Multi-Walled Carbon Nanotube （MWCNT） were incorporated into cement matrix to fabricate 3 groups nanocomposites, with associated the reference （Plain/C）. The critical damping ratios （ζ） and flexural strengths （σ） of these composites were investigated with free attenuation method in an elastic system, half-power bandwidth technique and subsequently three-point bending testing method, respectively, to evaluate the effect of USF or/and MWCNT additives on the damping and mechanical properties of cement matrix. Relative to the refer- ence, the infilling and pozzolan effect of USF additive has positive influence on the enhancement of the a of matrix, yet somewhat negative effect on that of ζ. The dislocation, viscous deformation effects of hollow nanotubes render the nanocomposite good damping behavior, yet the formation of defect and porosity with bad dispersion of MWCNT may jeopardize the enhancement of the α. There are dual positive effects on the ζ and α of the nanocomposite when with combinatory incorporation of USF and MWCNT, microstructure reveals there exist good cross linkages between USF, MWCNT and cement matrix, and the enhancement amplitude of the ζ and α can increase by 30.21%, 24. 13%, relative to the reference, respectively.