CEMENT

CEMENT 

             cement is building material which used in construction industry. Cement sets well under water and hardens quickly and attains strength. Cement differ from lime by the property that it does not slake but sets readily. cement possesses hydraulic properties to it a great extent and acquires more strength on setting. The setting power of cement is more than that of lime . In actual, cement is an calcarious substance which is used in more or concrete for construction. 

TYPES OF CEMENT 

• Ordinary Portland cement 
• Rapid Hardening cement
• Quick Setting cement 
• Low Heat cement 
• Portland Pozzolana cement

Ordinary Portland Cement

         It is the most common cement used in  the construction industry. It has a low resistance to chemical  attack and it has a medium rate of hardening. Chemical constituents of ordinary Portland cement are lime, silica, alumina, iron oxide, magnesia, Sulphur Trioxide, soda and potash. Out of the total production of cement ordinary Portland cement accounts for about 80 to 90 percent. The color of ordinary Portland cement is grey or greenish grey. It has rate of strength developement and rate of evolution of hear of hydration are medium. It has medium cracking resistance. 

Rapid Hardening Cement

       This cement is similar to ordinary Portland cement. It develops strength rapidly so as it is called as high early strength cement. It develops at the age of three days, the same strength as that is expected of ordinary Portland cement at seven days. The rapid are of development of strength is due to the higher fineness of grinding and higher C3S and lower C2S constant. A higher fineness of cement particles gives greater surface area for action of water and higher C3S results in quicker hydration. It is used for condstruction of important structures and under water works. This cement contains high percentage of cement. The lighter weight of rapid hardening cement and the shorter period of water curing make its use economical compared with the normal setting cement.

Quick setting Cement

           This cement sets very early. This property is brought out by reducing the gypsum content at the time of clinker grinding. this cement is required to be mixed, placed and compacted very early. It is mostly used in under construction. It is also useful for the purpose of grouting. 

Low Hear Cement 

         The hydration of cement is an exothermic action which produces large quantity of heat during hydration. This heat of hydration results in cracks in large body of concrete. So technologist produced a cement, which produces less amount of heat at a low rate during the process of hydration. This type of cement is evolved by reducing the contents reducing the contents of C3S and C3A which are the compounds evolving the maximum heat of hydration and increasing C2S.

Portland Pozzolana Cement 

      This cement is specially useful in marine and under-water construction. Pozzolana is the name given to volcanic ashes which is chiefly a siliceous material. Pozzolana cement is prepared by mixing and grinding clinkers and pozzolana together. Pozzolana, present in cement, reacts with the free lime liberated during hydration of cement and prevents disruption in in concrete. The pozzolana constituent shall not be less than 10% and not more than 25% weight of of Portland cement. Portland pozzolana cement produces less heat of hydration and offers greater resistance to the attack of water than ordinary Portland cement.

TEST OF CEMENT
TEST OF BRICKS