Evaluation of a long-lasting pavement patching material and surface treatment

Abstract

As the concrete pavement suffer from various degradation factors, maintenance and repair cost of pavement has been increased. Although there are various developed materials for the road repair, the existing repair materials containing ordinary Portland cement or hot mix asphalt may face degradation at the early curing phase due to the debondment of the repair material from the substrate. Owing to these problems, the magnesium phosphate cement was evaluated for a new road repair materials. Moreover, as a prevention method, the performance of the surface treatment was evaluated. The optimistic mix design of MPC mortar was determined in terms of the fundamental properties by modifying the ratio of activator and retarder. The hydration products and pore structure were determined by measuring X-ray diffraction and mercury intrusion porosimetry, respectively. The physical performance of MPC mortar was interpreted the interfacial pore distribution using BSE image analysis. The freezing and thawing test and rapid chloride penetration test were performed to evaluate the durability of MPC. As a result, the MPC shows high physical performance including compressive strength and accelerated setting. The tensile and flexural strengths also higher than OPC, accounting for 1.9 and 1.7MPa, respectively. It is presumed that the reduction of interfacial porosity may result in the increase of the adhesion of MPC mortar. Moreover, due to the reduction of the porosity at capillary, the MPC showed low penetrability and high resistance against frost damage. In terms of surface treatment, the ionic percolation was evaluated for silane and siloxine based products (SS Liquid and SS Crème). It was found that the surface treatment could significantly reduce the water absorption and chloride ingresses at all depths, due to a modification of the pore structure and/or generation of water repellent film on the surface. Thus, SS Crème could reduce a large margin for the chloride diffusivity, whilst SS liquid significantly lower the surface chloride concentration.