Impact Resistance of Polyurea-Coated High-Performance Cementitious Composites

Polyurea is a polymeric material that can be used to provide environmental protection and structural enhancement. In this study, a low modulus polyurea coating, having high elongation, high energy absorption capacities, and a fast gel time, was sprayed under field conditions onto the surfaces of high-performance cementitious composites (HPC2). Flexure tests were conducted to measure toughness so that predictions could be made regarding the impact performance of two uncoated and coated matrices, one containing polyvinyl butyral (PVB) as the only aggregate, the other with polyvinyl alcohol (PVA) fibers added for reinforcement. Results from the flexure tests showed that encapsulation by plain polyurea increased the flexural strength of specimens by at least 60%. Results from drop-weight tests showed that the PVA fibers helped to improve impact resistance. A visible reduction in damage was seen when polyurea was applied to one surface, more so by coating the tension side opposite the striker. Coating both surfaces further increased impact resistance.