Study on the effect of polyacrylonitrile fiber on the properties of steel slag-cement cementitious materials

Substitution of cement with steel slag (SS) is conducive to energy conservation and environmental governance. This work aimed to improve the volume stability and mechanical properties of SS-cement cementitious materials by incorporating polyacrylonitrile (PAN) fiber into SS. The rheological property, volume stability, mechanical strength, and the corresponding mechanisms of SS-cement sample with PAN fiber were investigated. A moderate addition of PAN fiber effectively improved the volume stability and mechanical properties of SS-cement cementitious materials. Compared with the reference sample, the compressive strength of sample added 0.1% PAN fiber was increased by 12.7%, and its autoclave expansion rate was reduced by 19.44%. Rheological tests showed that PAN fiber had only a slight effect on the rheological properties of SS-cement slurry samples. The hydration products of SS-cement cementitious materials were mainly Ca(OH)(2) and calcium silicate hydrate (C-S-H). The hydration product could be adhered to PAN fiber and finally cover the surface of the fiber to form a dense product layer, causing a high roughness at the fiber-matrix interface and inhibiting the volume expansion.