Magnesium alloy is known as the green engineering metal structure material in 21st century. The massive magnesium slag produced in China via Pidgeon process has become a crucial problem. Much solid waste can be reused in building materials preparation,and magnesium slag are no exception but are rarely studied. The researches mainly concerned in the cementitious materials prepared from magnesium slag coupled other solid wastes and cement,so the hydration mechanism of magnesium slag and its effect on cement hydration is not clear yet. In this work, the properties,composition and structural of ultrafine magnesium slag powder-cement composites cementitious materials (MS-C)were investigated,and the influence of ultrafine magnesium slag powder on the hydration process of MS-C were discussed,further unlocking the cooperative hydration mechanism of MS-C. The low reactive γ-C2 S is the main form of dicalcium silicate in magnesium slag,so the ultrafine grinding is the key way to improve its filling effect. The content of pore larger than 1 000 nm in cement pastes was reduced from 7. 98% to 6. 83% when 30% of ultrafine magnesium slag powder was blended. The fluidity of MS-C fresh pastes increased with the addition of ultrafine magnesium slag powder under the action of superplasticizer,but the effect was opposite when there was no superplasticizer. The hydration and weak cementing of ultrafine magnesium slag powder with low dosage can enhance the contribution of its filling effect to strength,in which process more Ca(OH)2 and C-S-H gel were formed. Therefore,MS-C with low dosage of ultrafine magnesium slag powder obtained better mechanical properties than cement 28 d. The conclusions on the hydration characteristics of ultrafine magnesium slag powder-cement made in this study may provide a theoretical basis for improving the utilization value and rate of magnesium slag. © 2023 Cailiao Daobaoshe/ Materials Review. All rights reserved.
