Multifunctional properties of carbon nanotube/fly ash geopolymer nanocomposites
Multifunctional properties of carbon nanotube/fly ash geopolymer nanocomposites
复制标题
DOI：
10.1016/j.conbuildmat.2013.08.007
复制
发表时间：
2013-12
影响因子：
7.4
通讯作者：
M. Saafi;K. Andrew;P. L. Tang;David McGhon;Steven Taylor;Mahubur Rahman;Shangtong Yang;Xiangming Zhou
中科院分区：
文献类型：
--
作者：
M. Saafi;K. Andrew;P. L. Tang;David McGhon;Steven Taylor;Mahubur Rahman;Shangtong Yang;Xiangming Zhou
基于粉煤灰的地质聚合物目前被认为是普通波特兰水泥（OPC）的可行替代品，这是由于其具有多方面的益处，例如成本效率、化学稳定性、耐腐蚀性、快速强度增加速率、低收缩性和抗冻融性。然而，地质聚合物往往比OPC更脆，因此由于安全问题而不适合混凝土结构。具有改进的电性能的地质聚合物也可以用作能够检测其自身结构损伤的自传感材料。因此，本文旨在研究多壁碳纳米管（MWCNTs）对粉煤灰（FA）土聚物复合材料的力学和电学性能的影响。合成了含有不同MWCNT浓度（0.0重量%、0.1重量%、0.5重量%和1.0重量%）的地聚合物基质，并测试了它们的机械性能（即，弯曲强度、杨氏模量、弯曲韧性和断裂能）、电导率和压阻响应。扫描电子显微镜（SEM）被用来评估多壁碳纳米管在基体中的分布质量，并确定其裂纹桥接机制。实验结果表明，多壁碳纳米管在0.1和0.5重量%的基体中均匀分布，它们分布不佳，严重团聚在基体中的1重量%。实验结果还表明，多壁碳纳米管的加入，提高了弯曲强度，杨氏模量和弯曲韧性高达160%，109%和275%，分别。多壁碳纳米管还提高了断裂能，并将电导率提高了194%。地质聚合物纳米复合材料表现出压阻响应与微裂纹扩展的高灵敏度。
Fly ash-based geopolymers are currently being considered as a viable replacement to ordinary Portland cement (OPC) due to multifold benefits such as cost efficiency, chemical stability, corrosion resistance, rapid strength gain rate, low shrinkage and freeze-thaw resistance. However, geopolymers tend to be more brittle than OPC and thus unsuitable for concrete structures due to safety concerns. Geopolymers with improved electrical properties can also be used as self-sensing materials capable of detect their own structural damage. Therefore, this paper is aimed at investigating the effect of multiwalled carbon nanotubes (MWCNTs) on the mechanical and electrical properties of fly ash (FA) geopolymeric composites. Geopolymeric matrices containing different MWCNTs concentrations (0.0%, 0.1%, 0.5% and 1.0% by weight) were synthesized and their mechanical properties (i.e., flexural strength, Young’s modulus, flexural toughness and fracture energy), electrical conductivity and piezoresistive response were determined. A scanning electron microscope (SEM) was employed to evaluate the distribution quality of MWCNTs within the matrix and determine their crack-bridging mechanism. The experimental results showed that the MWCNTs were uniformly distributed within the matrix at 0.1 and 0.5-wt% and they were poorly distributed and severely agglomerated within the matrix at 1-wt%. The experimental results also showed that the addition of MWCNTs increased the flexural strength, Young’s modulus and flexural toughness by as much as 160%, 109% and 275%, respectively. The MWCNTs also enhanced the fracture energy and increased the electrical conductivity by 194%. The geopolymeric nanocomposites exhibited a piezoresistive response with high sensitivity to micro-crack propagation.