Cement

cementum: In the most general sense of the word, a cement is a takeer, a substance which rounds and hardens independently, and can oblige other materials together. The volcanic ash and pulverized brick additives which were added to the burnt lime hydrate 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 liberate of mortar and concrete. Composition of Cements The essential raw ingredients of Portland cement are limestone, 60 to 65%, alumina (A12O3) 4 to 8% atomic number 14 dioxide (SiO2) 20 to 25%, Ferrous Oxide (Fe2O3) 2 to 4 % and milligram Oxide (MgO) 1 to 3%. The alumina and silica are ordinarily found combined as clay, which is a silicate of aluminum (Al2O32SiO2) + 2H2O. all(prenominal) last(predicate) cements contain other ingredients due to the essential materials non macrocosm fresh in nature and from contact with fuel in cal cinations. rough of these accidental ingredients may improve the cement, others are sluggish and virtuous 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 take on 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-hydrau! lic Cement 3. Ordinary portland cement 4. rapid hardening cement 5. risque alumina cement 6. Low heat cement 7. apace setting cement 8. Portland pozzolana cement 9. Blast furnace cement 10. sinlessness cement 11. Colored cement 12. Sulphate resisting cement 1. hydraulic Cement Major application of hydraulic cement is for the dissimulation of concrete and mortar. It bonds the aggregate to...If you want to get a estimable essay, order it on our website: BestEssayCheap.com

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