Study on 32.5N/mm2 Grade Cement Using Slowly Cooled Blast Furnace Slag and Granulated Blast Furnace Slag.

The 32.5 N/mm2 grade cement (325 cement) using slowly cooled blast furnace slag and granulated blast furnace slag, has a tendency of small fluidity change in course of time compared with the 325 cement prepared with the ordinary portland cement (OPC) and limestone powder (LSP). On the other hand, this has a long setting time, and is slow in developing the early age strength. However, those were improved by substituting the high early strength cement for OPC. In addition, the compressive strength in 28 days was equal to the 325 cement from OPC and LSP, and the neutralizing resistivity has been improved keeping the high resistivity of the blast furnace slag cement to chloride ion permeation as it is. Besides, ecological evaluation results proved that the carbon discharge due to the cement manufacturing and the natural resources of limestone consumption will be largely reduced, thereby this 325 cement can be a cement of small environmental load. The industrial byproduct of the blast furnace slag is proportioned more than in the blast furnace slag cement, therefore this 325 cement can be serviceable also in view of increasing the byproduct reuse.