Effect of mechanical grinding time on the particle groups characteristics and activation effect of Yellow River sediment

Abstract

Yellow River sediment(YRS) is an abundant resource of dredged sediment, and has found wide applications as various construction materials. However, its potential activity has seldom been reported. In this study, the activity of YRS was stimulated by mechanical grinding. The particle characteristics after different grinding times were investigated and the mechanism of activating YRS was illustrated. In the initial grinding stage (within 25 min), the size of YRS was significantly reduced and the particle size distribution (PSD) was uniform. In the ultrafine grinding stage (25–70 min), the particle size and distribution did not change further. Instead, the mineral crystal structure was destroyed, leading to a reduced crystallinity and an increased number of broken bridge oxygen bonds. After YRS was ground for 40 min, the activity index reached the maximum. YRS exhibited significantly improved activity, providing a theoretical basis for its application as supplementary cementitious materials to reduce cement dosage. When the grinding was further increased to 70 min, the activity of YRS decreased due to the reorganization of chemical bonds.