Properties and Microcosmic Mechanism of Coral Powder Modified Asphalt in Offshore Islands and Reefs Construction

Abstract

The application of waste coral fragments from natural weathering, harbor construction and channel excavation to infrastructure construction on offshore islands can help alleviate the problems of shortage of traditional materials, land use of waste materials, and long-distances transport. In order to promote the comprehensive application of coral materials in road engineering construction on offshore islands, and to develop road pavement materials with good service performances and economic and environmental benefits, this paper studies the base properties, high-temperature rheological properties, and microstructure of coral powder (CP) modified asphalt through indoor experiments. The base properties tests (penetration, softening point and ductility) showed that the incorporation of CP increased the stiffness and high-temperature stability of the asphalt, but decreased the ductility of the asphalt. The optimal dosing of CP in virgin asphalt (VA) and styrene-butadiene-styrene-modified asphalt (SA) is 12% and 15%, respectively. The results of viscosity and high-temperature rheology tests showed that the right amount of CP could improve the high-temperature rheological properties and resistance to permanent deformation of asphalt, but superfluous CP tends to have a negative effect. Microscopic test results show that in the recommended dosage, the combination effect of CP and asphalt is better. CP-modified asphalt is mainly based on physical modification.