碳纳米管改性泡沫混凝土物理力学与阻尼性能

Physico-mechanical and damping performances of carbon nanotubes modified foamed concrete

以普通硅酸盐水泥为基体,结合化学发泡、表面活性剂超声分散纳米纤维法,制备碳纳米管(MCNT)改性泡沫混凝土(MCNT/FC)。在研究MCNT/FC的基本物理性能(干密度ρd、吸水率Wc、抗压强度fc)基础上,进一步采用平板导热法、自由激振-半功率带宽识别法研究其隔热保温性能(导热系数λc)及阻尼减振性能(阻尼比ζc),最后通过SEM分析微观结构。结果表明,相比于空白泡沫混凝土,适量中空、多层的MCNT(0.05%)可均匀分散于泡沫混凝土中,微观空隙变少、变小,实现对基体的增韧补强与稳泡成核效果,fc、Wc、ρd、λc分别提高50.0%、降低15.3%、提高13.3%、降低77.3%,性能达到最佳,但ζc未能明显提高;MCNT掺量0.10%时,fc增幅为30.0%,且ζc达到最大(0.060 1),增幅为36.2%,拥有平衡的力学与阻尼性能。泡沫混凝土内部细小孔隙、MCNT良好的层间摩擦力及其与水化产物间的内摩阻力对阻尼性能均有促进作用。

Using ordinary Portland cement as matrix,the multi-walled carbon nanotubes（ MCNT） modified foamed concrete（ MCNT/FC） was prepared combining with the methods of chemical foaming,surfactant ultrasonic nanofiber dispersion. On the basis of the study of physico-mechanical properties of the MCNT/FC（ dry density ρd,water absorption Wc,compressive strength fc）,its heat insulation performance（ thermal conductivity λc） and damping vibration reduction performance（ damping ratio ζc） was further studied by the method of flat heat conduction,free agitation and half-power bandwidth identification,respectively. Finally,its microstructures was analyzed through SEM. The results showcompared with the blank foamed concrete,hollow,multi-layer MCNT（ 0.05%by the mass） can be dispersed in foamed concrete uniformly,the microscopic voids to be fewer and smaller,and can implement the reinforcing and bridging effect and bubble nucleation effect of the matrix. the fc,Wc,ρd,λcincreases up to 50.0%,decreases up to15.3%,increases up to 13.3%,decreases up to77.3%,respectively,achieving the best performances,but ζcfails to improve significantly. When M CNT loading is 0.10%by the mass,fcincreases up to 30.0%,ζcreaches the maximum value（ 0.060 1）,and increases up to 36.2%,achieving the balanced mechanical and damping properties. These attribute to the tiny pore internally generated by foamed concrete and good friction between the layer in MCNT as well as the inner friction resistance between the hydration products.