In this paper, S95 grade ultrafine mineral admixture was prepared by water quenched manganese slag and fly ash 1:1 compound mechanical ball milling to a specific surface area of 714 m²/kg. Its activity index was 86.8% at 7d and 96.3% at 28d. The S95 ultrafine mineral admixture prepared by ball milling has the characteristics of small particle size, high specific surface and high activity. Mixing with powders of different particle sizes, such as cement and silica fume, is helpful to improve particle gradation, reduce its pore structure and increase its compacting property for UHPC whose raw materials are fine aggregate. Ultra-high performance concrete (UHPC) was prepared by using the obtained ultrafine mineral admixture based on orthogonal test. The effects of different factors on the workability, mechanical properties, hydration heat and microstructure of UHPC were studied. The results show that when the silica fume content is 10%, the mineral admixture content is 10%, the binder-sand ratio is 1.1, and the water-binder ratio is 0.17, the fluidity of UHPC slurry can reach 261 mm, the compressive strength of 7d and 28d age can reach 128 MPa and 154.6 MPa, respectively. The hydration heat release of cementitious materials in 3d was 139.8 J/g. In terms of solid waste resource utilization, S95 grade ultrafine mineral admixture prepared by water-quench manganese slag and fly ash can replace 10% silica fume for the preparation of UHPC. It can not only solve the utilization problem of high added value of water quench manganese slag, but also reduce the preparation cost of UHPC to a certain extent.

As supplementary cementitious material, glass powder has been widely used in concrete, and many investigations on the mechanical properties of glass powder concrete have been carried out. However, there is a lack of investigations on the binary hydration kinetics model of glass powder-cement. Based on the pozzolanic reaction mechanism of glass powder, the purpose of this paper is to establish a theoretical model of the binary hydraulic kinetics model of glass powder-cement to investigate the effect of glass powder on cement hydration. The hydration process of glass powder-cement mixed cementitious materials with different glass powder contents (e.g., 0, 20%, 50%) was simulated using the finite element method (FEM). The numerical simulation results are in good agreement with the experimental data of hydration heat in the literature, which verifies the reliability of the proposed model. The results show that the glass powder can dilute and accelerate the hydration of cement. Compared to the sample with 5% glass powder content, the hydration degree of the glass powder decreased by 42.3% for the sample with 50% glass powder content. More importantly, the reactivity of the glass powder decreases exponentially with the increase in the glass particle size. In addition, the reactivity of the glass powder tends to be stable when the glass particle size is greater than 90 μm. With the increase in the replacement rate of the glass powder, the reactivity of the glass powder decreases. When the replacement rate of the glass powder is greater than 45%, the concentration of CH reaches a peak at the early stage of the reaction. The research in this paper reveals the hydration mechanism of glass powder and provides a theoretical basis for the application of glass powder in concrete.