摘要：
Cement matrix is increasingly becoming the relatively weak phase, which limits the further enhancement of ballistic impact resistance of high performance cement composites. Cellulose-based fiber is a promising strengthening agent for cement matrix due to its internal curing and reinforcement effect. This study presents a comparative investigation on the effect of two cellulose-based fibers, synthetic wood pulp (SWP) and microfibrillated cellulose (MFC), on the ballistic impact resistance, as well as shrinkage and physical/mechanical properties of high strength mortars (HSMs). Ballistic impact resistance is evaluated at two different velocities of approximately 400 m/s and 675 m/s, using conical-nosed 8-mm-diameter projectiles. The results indicate that incorporating SWP or MFC leads to a considerable enhancement of ballistic impact resistance, in terms of reduced penetration depth, crater diameter and volume. The beneficial effect of SWP and MFC is more pronounced at 675 m/s in comparison to that at 400 m/s. The MFC appears more effective in decreasing the penetration depth and crater volume in comparison to SWP. The addition of SWP and MFC is also beneficial for reducing autogenous/drying shrinkage and improving compressive/flexural strengths and hardness of HSMs. The results of this study provide insights on further improving the impact resistance of HSMs for protective structures.
