Paper Title
Differences in the Internal Structure of Nanofiber-Cement Matrices Concerned with the Change of Cement Compressive Strength

Abstract
This study presents the effect of the hybrid nanofiber of nylon 66 and silica seeds in improving the compressive properties of cement-based materials. The observations from compression tests show an increase of 38 % and 24 % in compressive strength and toughness of cement pastes modified by the hybrid nanofibers, respectively. The behaviors of fibers inside the internal structures of cement paste were investigated through SEM images, showing the enhancement in the adhesive of nanofibers between cement hydration products and creating extra C-S-H products through the extra pozzolanic reactions. Keywords - Hybrid nanofibers, Nylon 66, Silica, Cement, SEM.