Preparation and application of fine-grinded cement in cement-based material

Low water/cement ratio in cement-based materials can be obtained with the incorporation of the superplasticizer. However, another problem can be found: the hydration degree of the cement minerals is obviously reduced. Generally, the hydration degree can be promoted with finer particle size, while this also brings about the problem of too fast hydration process at very early age, resulting in little contribution to the mechanical performance. Additionally, the stability in storage and transportation process is also a concern that cannot be ignored. In this study, the fine-grinded cement (GC) was prepared in the presence of surface modifier and micro-grinding media (MGM), with intention to control the early hydration process and promote the grinding efficiency. The hydration products, porosity and interfacial transition zone (ITZ) of Portland cement (PC) paste or mortar with GC were investigated. The results show that the efficiency of GC preparation can be promoted and the hydration process in the early age can be controlled with the addition of the surface modifier and MGM. Partial replacement of PC by GC, with an optimal dosage of 20% GC, can obviously increase the cementitious efficiency, resulting in an obvious enhancement to the compressive strength. The hydration degree, pore structure and the microstructure in ITZ can be improved in the presence of GC, in comparison with PC single system. Such results can provide guidance on the design of the cementitious component system in concrete mixing plant.