Characterization of mechanical behavior and mechanism of calcium carbonate whisker-reinforced cement mortar

• Published in: Construction & building materials Vol. 66; pp. 89 - 97
• Main Authors: Cao, Mingli, Zhang, Cong, Lv, Haifeng, Xu, Ling
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15-09-2014; Elsevier B.V
• Subjects: Calcium carbonate; Calcium carbonate whisker; Chemical properties; Fibrous material; Mechanical properties; Mechanical property; Mortar; Reinforcement; Reinforcing mechanism; China; Reinforcement; Fibrous material; Reinforcing mechanism; Mortar; Mechanical property; Calcium carbonate whisker
• ISSN: 0950-0618
• DOI: 10.1016/j.conbuildmat.2014.05.059

•CaCO3 whisker was incorporated into cement mortar.•Mechanical behavior and reinforcing mechanism were presented.•CaCO3 whisker-reinforced mortar showed satisfied properties.•An appropriate weak matrix is very beneficial to CaCO3 whiskers to play their roles.
In order to reinforce cement mortar, a new kind of micro-fibrous material, calcium carbonate whisker (CaCO3 whisker), was incorporated in this study. Microstructure, mechanical properties and reinforcing mechanism of this composite were characterized. It was found that the addition of CaCO3 whisker improved not only the compressive and flexural strength of cement mortar, but also the load–deflection curves and work of fracture. Further work using mercury intrusion porosimetry tests confirmed the filler effect and the refining of the pore distribution of whiskers in cement mortar. Scanning electron microscopy showed that the microscopic mechanism primarily consists of whisker pullout, crack deflection, whisker-cement coalition pullout, whisker bridging and whisker breakage. These mechanisms are related to the matrix strength. As compared to the strong matrix, the weak matrix that was modified with CaCO3 whisker achieved the highest increase in strength and toughness of the cement mortar. This is likely attributed to the crack deflection mechanism, which is weakened by the strong interfacial bonding between the CaCO3 whisker and cement matrix in the stronger mortar matrix.