Evaluation of carbon fiber dispersion in cement-based materials using mechanical properties, conductivity, mass variation coefficient, and microstructure. (10th January 2021)

• Record Type: Journal Article
• Authors: Zhu, Hongbo; Zhou, Haiyun; Gou, Hongxiang
• Is Part Of: Construction & building materials. Volume 266(2021)Part A
• Publication Date: 2021-01-10
• Subjects: Carbon fiber -- Dispersion evaluation -- Carbon fiber reinforced cement-based composites; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.120891
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: ·The ultrasonic vibration and dispersants are used to disperse carbon fibers in the mortar. ·The effect of multiple variables on the mechanical and electrical properties of CFRC are studied. ·The modified mass variation coefficient is proposed to evaluate the fiber dispersion directly. ·The micro information of CFRC is investigated by SEM, XRD, and BET. Abstract: Uniform dispersion of carbon fibers is key to improving the properties of carbon fiber reinforced cement-based composites (CFRC). For the sake of high reliability, several methods were applied to measure the dispersed state of carbon fibers in the matrix. The mechanical and electrical properties of CFRC are assessed directly, while the mass variation coefficient, SEM, XRD, and BET appraise the dispersity indirectly. Experimental results indicate that the high fiber content is beneficial to the promotion of toughness and conductivity of CFRC, while the uniformity becomes enhanced by the higher dispersant content; the carboxymethyl cellulose sodium (CMC) has outstanding dispersion effect compared with other additives. Moreover, the ductility of CFRC is more applicable for estimating the fiber dispersion, which eliminates the matrix interference, and the strength is considerably affected by the matrix defects. Finally, the fiber content has an impact on the macro-level properties of the composites, but the hydration products of mortar are hardly influenced by the dispersants.