Cement

Cement:
In the most general sense of the word, a cement is a takeer, a substance which sets and hardens independently, and can bind other materials together. The volcanic ash and pulverized brick additives which were added to the burnt calx to obtain a hydraulic binder were later referred to as cement. Cements used in construction be characterized as hydraulic or non-hydraulic. The most important use of cement is the issue of mortar and concrete.
Composition of Cements
The essential raw ingredients of Portland cement are limestone, 60 to 65%, alumina (A12O3) 4 to 8% silicon dioxide (SiO2) 20 to 25%, Ferrous Oxide (Fe2O3) 2 to 4 % and magnesium Oxide (MgO) 1 to 3%. The alumina and silica are commonly found combined as clay, which is a silicate of aluminum (Al2O32SiO2) + 2H2O. every last(predicate) cements contain other ingredients due to the essential materials non macrocosm pure in nature and from contact with fuel in calcinations. Some of these accidental ingredients may improve the cement, others are sluggish and harmless except that they exist in such mensuration as to displace essential ingredients, and others are positively harmful, if resign in quantity, because of the chemical action they produce. There are accidental ingredients usually amounting to about 5%, but these must not include everyplace 1.75% anhydrous sulphuric acid (So3), nor over 3% of magnesia (MgO).



Excess of clay causes a cement to set quickly, while excess of lime causes it to set easy or imperfectly. Iron oxide gives cement its color.
Types of Cement
1. hydraulic cement
2. Non-hydraulic Cement
3. Ordinary portland cement
4. rapid hardening cement
5. High alumina cement
6. Low heat cement
7. rapidly setting cement
8. Portland pozzolana cement
9. Blast furnace cement
10. White cement
11. Colored cement
12. Sulphate resisting cement
1. Hydraulic Cement
Major application of hydraulic cement is for the fabrication of concrete and mortar. It bonds the aggregate to...If you want to get a skillful essay, order it on our website: Orderessay



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