Design and Experimental Verification of Asphalt‐Based Material for Grouting of Prestressed Structure

Abstract

The quality of the grouting is an important factor affecting the durability of prestressed structures, especially in corrosive environment with stray current. Uncompacted grouting will lead to rapid corrosion and failure of steel strand. In this paper, an asphalt-based material as grouting material was designed to solve this problem due to the characteristics of asphalt material as impermeability, anticorrosion, and insulation. The viscosity and shear strength were considered as the main performance parameters of the grouting material for prestressed grouting. The composition and proportion of the asphalt-based material were determined through the tests, including natural asphalt (rock asphalt) being 12.5% and admixture (slaked lime and cement) being 40%. For this grouting material, the shear strength was 697.21 kPa at normal temperature, and the suitable grouting temperature was 115°C. Then, the grouting test of the prestressed concrete beam was carried out to verify the groutability of this material. The grouting slurry can be filled with prestressed duct, and the temperature stress of the concrete near the duct was lower than 1.4 MPa, which met the safety requirement of the concrete. This study provides a new option for guaranteeing the quality of grouting and improving the durability of prestressed structures in corrosive environment.