On the grinding effects of high-silicon iron tailings.

The main chemical component of high-silicon iron tailings (HSITs) is SiO; HSITs also include some oxides such as AlO and CaO. Mechanical activation can reduce the particle size of HSITs and enhance their pozzolanic activity such that they can be used as a type of mineral admixture for cement-based materials (CBMs). This study aims to investigate the mechanical activation (ultrafine grinding) effects of HSITs, including physical and crystallization structure effects.

Design of Concrete Mix Proportion Based on Particle Packing Voidage and Test Research on Compressive Strength and Elastic Modulus of Concrete.

According to the basic principle of dense packing of particles, and considering the interaction between particles, a dense packing model of granular materials in concrete was proposed. During the establishment of this model, binary particle packing tests of crushed stone and sand were carried out. The fitting analysis of the test results determines the relationship between the particle size ratio and the remaining volume fraction of the particle packing, and then the actual void fraction of the particle packing was obtained, based on which the water-binder ratio was combined to determine the amount of various materials in the concrete.