Effect of carbon nanofibers on autogenous shrinkage and shrinkage cracking of cementitious nanocomposites

The addition of carbon nanofibers (CNF) has the potential to have a major impact in the concrete materials industry due to the high modulus and specific surface area of CNF. Past research has focused on characterization of the mechanical and flexural strength behavior of CNF-modified cement-based materials. In this study, the influence of CNF on the autogenous shrinkage and shrinkage cracking of cement mortar is investigated. It is found that CNF is not only able to mitigate the autogenous shrinkage of cement paste and mortar but is also effective in restraining shrinkage cracking. By comparing the fiber count in both paste and mortar, the effect in mortar is more pronounced than in paste, which suggests a modification of the interface area between the aggregate and the paste area. Targeting the large autogenous shrinkage of high-performance concrete at early age, CNF combines the beneficial effects of the traditional microfiber reinforcement and shrinkage-reducing admixture.