The bulk density of OPC varies considerably depending on how it is stored and handled as voids are considered in it.įor example, during transportation, cement gets consolidated because of vibration, thus increasing bulk density. It is an important measure based on which cement is graded. It is the compressive strength of cement at the end of 28 days. While final setting time is the time at which the cement loses its plasticity completely. Initial setting time is the time at which cement paste starts losing plasticity. Setting time of cement is related to the plasticity of cement paste. It is expressed in terms of the specific surface of cement 2. It is a measure of the size of cement particles. Ordinary Portland Cement Characteristics Physical Characteristics of Ordinary Portland Cement 1. It is used for general construction where special properties of cement type II, III, IV, and V are not required. Out of these, Type I cement is ordinary portland cement. There are five types of cement as per ASTM classification –Type I, Type II, Type III, Type IV, and Type V. Optimum particle size distribution and super crystallised structure account for the high strength of 53 grade cement. Ordinary Portland Cement 53 Gradeĥ3 grade Ordinary Portland Cement has a minimum compressive strength of 53 N/mm 2 at 28 days. It is the most commonly available cement grade in the Indian market today. Ordinary Portland Cement 43 GradeĤ3 grade Ordinary Portland Cement has a minimum compressive strength of 43 N/mm 2 at 28 days. The compressive strength should be tested as per the test procedure mentioned in IS: 4031- 1988. The actual strength obtained is much more than specified.
IS: 10262 has classified cement based on 28-day compressive strength as follows: Cement TypeĬlassification of Cement as per IS: 10262 Ordinary Portland Cement 33 Gradeįor OPC grade 33 cement, the compressive strength should not be less than 33 N/mm2 at28 days. It has a faster rate of development of strength.
Higher grades of cement can be achieved by improving the quality of cement. Hence, modern cement plants were established. With the advancement in cement technology, soon more and more factories started producing high grade cement. Therefore, Railways developed their own specification for sleeper cement that has minimum characteristic strength of 52.5 N/mm2 at 28 days. But OPC 33-grade could only give 33 N/mm2. In 1973-75, Indian Railway introduced prestressed concrete sleepers whose minimum characteristic strength requirement was 50 N/mm2. Until 1973, however, only grade 33 cement was available.
USA and UK have one specification for cement. To know detail step by step process of cement manufacture and comparison of wet and dry process, CLICK HERE. The clinkers are then grinded into fine powder and stored in silos.As a result, clinkers are obtained to which a small amount of gypsum is added to prevent flash setting.These are then mixed dry or wet and then crushed and grinded in a kiln.Calcareous materials like cement rock, limestone, chalk, marine shell, etc and argillaceous materials like clay, shale, slate, blast furnace slag, etc are taken first in specified proportions.In general, the manufacture of OPC can be understood as follows: Production of Ordinary Portland Cement is done either by wet process or by dry process. Gypsum is added in OPC at the time of grinding to adjust the setting time of cement and to prevent the flash setting of cement. Use of Gypsum in Ordinary Portland Cement To know the functions of these oxides in cement, Read Functions of Ingredients in Cement. The general composition of OPC is tabulated below: Oxide These can be cementitious materials or filler materials, which can enhance the workability or water retention capacity of cement.
Ordinary Portland Cement composition is given below:ĩ5-100 % portland cement clinker is used while 0-5 % of minor constituents are present. It possesses binding properties to bind the materials together as well as adhesive properties. Ordinary Portland Cement Definition: Ordinary portland cement is a cementing material obtained by fine grinding of portland clinkers with a little amount of gypsum to adjust the setting time and prevent flash setting. Chemical Characteristics of Ordinary Portland Cement.Physical Characteristics of Ordinary Portland Cement.Ordinary Portland Cement Characteristics.Manufacture of Ordinary Portland Cement.Use of Gypsum in Ordinary Portland Cement.Composition of Ordinary Portland Cement.
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