Experimental Study on the Strengthening Effect of Polyaspartate Polyurea Lining on Concrete Pipes

ABSTRACT In this study, the mechanical properties of a novel polyaspartate polyurea (PAEP) material and its effectiveness in enhancing the structural strength of concrete pipes with varying damage levels were experimentally investigated. Results show that PAEP is a high densification matrix with superior strength performance, particularly in tensile and bending resistance. When applied as a lining for concrete pipes, PAEP forms a tightly fitted contact surface. A 3–6 mm PAEP lining enhances the load‐bearing capacity and stiffness of the damaged concrete pipes by about 71.2%–172.2% and 46.7%–150.4%, respectively. PAEP linings alter the failure process of concrete pipes, transforming instantaneous cracking into progressive cracking. PAEP lined pipes initially develop cracks near the spring lines but do not undergo complete failure until cracks occur near the crown/invert, which contributes to the enhanced structural strength of the pipes. The findings here provide a foundation for developing an innovative spray applied pipe lining rehabilitation technology using PAEP.