Prior to 1987, theDIFFERENT GRADES OF CEMENT
Prior to 1987, there was only one grade of Ordinary Portland Cement which was governed by IS 269-1976. After 1987 higher-grade cements were introduced to India. The Ordinary Portland Cement was classified into three grades, namely 33 grade, 43 grade and 53 grade depending upon the strength of the cement at 28 days when tested as per IS 4031-1988. If the 28-day strength is not less than 33 N/mm2, it is called 33 grade cement. If the 28-day strength is not less than 43 N/mm2, it is called 43 grade cement. If the 28-day strength is not less than 53 N/mm2, it is called 53 grade cement. But the actual strength obtained by the cement at the factory is much higher than the BIS specification. Table 4.3 shows compressive strength of different grades of cement.
Table 4.3 Compressive Strength of Different Grades of Cement
N.S. – Not specified
The compressive strength of Ordinary Portland Cement increases with time. For example, 33 grade OPC (IS 269-1989) acquires a compressive strength of 16 N/mm2 at 3 days, 22 N/mm2 at 7 days and 33 N/mm2 at 28 days.re was only one grade of Ordinary Portland Cement which was governed by IS 269-1976. After 1987 higher-grade cements were introduced to India. The Ordinary Portland Cement was classified into three grades, namely 33 grade, 43 grade and 53 grade depending upon the strength of the cement at 28 days when tested as per IS 4031-1988. If the 28-day strength is not less than 33 N/mm2, it is called 33 grade cement. If the 28-day strength is not less than 43 N/mm2, it is called 43 grade cement. If the 28-day strength is not less than 53 N/mm2, it is called 53 grade cement. But the actual strength obtained by the cement at the factory is much higher than the BIS specification. Table 4.3 shows compressive strength of different grades of cement.
Table 4.3 Compressive Strength of Different Grades of Cement
N.S. – Not specified
The compressive strength of Ordinary Portland Cement increases with time. For example, 33 grade OPC (IS 269-1989) acquires a compressive strength of 16 N/mm2 at 3 days, 22 N/mm2 at 7 days and 33 N/mm2 at 28 days.