Ordinary Portland Cement - an overview | ScienceDirect
According to Portland Cement, Ordinary Portland Cement (GB175-1999), the national standard, the strength grades of ordinary cement can be divided into: 32.5, 32.5 R, 42.5, 42.5 R, 52.5, 52.5 R, and their ages should be no less than the numerical value in Table 4.3.The initial setting time of ordinary cement should not be earlier than 45 min, and final setting time should not be later
