Study on the dense structure and properties of cement-stabilized coral aggregates

Abstract

The performance of cement stabilized coral aggregates semi-rigid base of pavement with coral reef limestone fragments and biological debris as the main materials is essential in the current reef engineering constructions. The performance of inorganic mixtures such as cement-stabilized coral aggregates mainly depends on the packing state of aggregates and the interfacial bonding among each component. Via digital image analysis theory, a simulation model of the dense packing of particles method was established, considering the influence of arbitrary particles shape distribution, upper limit of particles size, and aggregates gradation. The influencing mechanism of different factors on the packing state was revealed. It was found that the dense packing of coral aggregates is a strong suspension dense structure which did not form the skeleton structure. The strengthening mechanism of the coral particle-coated cement slurry was studied through the experimental analysis of the pore structure of coral rocks and debris particles and the crushing strength of particle-coated cement slurry, combined with the microhardness test of the cement- coral particle interface and the analysis of hydration products. The physicochemical excitation mechanism of hydration products densification，“physical interlocking” and “micro pump” effect at the interface of the cement-coral particle was revealed. Furthermore, based on the macroscopic mechanical properties of cement stabilized coral aggregates, the optimal design ratio of coral aggregates with upper limit particle size of 53mm, fine aggregates content of 45% and cement content of 8% was proposed. The findings of this study can provide a reference for the design and application of cement stabilized coral aggregates semi-rigid pavement base.