Effect of Electrospun Nanofiber Additive on Selected Mechanical Properties of Hardened Cement Paste

This study presents an estimation of the mechanical property enhancing mechanism of electrospun-nanofiber-blended cementitious materials. Four types of electrospun nanofibers (NFs) were introduced into Portland cement: nylon 66 nanofibers, tetraethyl orthosilicate/polyvinylpyrrolidone nanofibers (TEOS/PVP), hybrid nanofibers containing carbon nanotubes (CNTs) and nylon 66, and hybrid nanofibers containing carbon nanotubes and TEOS/PVP (CNTs-TEOS/PVP NFs). Due to the mechanical strength results, there was an increase of 27.3% and 33.4% in compressive strength when adding TEOS/PVP nanofibers and the hybrid nanofibers containing carbon nanotubes and TEOS/PVP into the pastes, respectively. In addition, there was an increase of 25.7% and 54.3% in tensile strength when adding nylon 66 nanofibers and the hybrid nanofibers containing carbon nanotubes and nylon 66 into the pastes, respectively. The highest toughness of 61.7% was obtained by the paste blended with CNTs-TEOS/PVP NFs. The results observed from scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis clarified the change in the microstructure of the modified pastes, as well as the mechanical property enhancing mechanism of the electrospun-nanofiber-blended cementitious materials.