Category: Cement

Ordinary Portland Cement should possess certain physical and chemical properties for the best performance when it is used in a structure. Further, it is possible to compare the quality of cement from different sources for proper selection. Frequent tests are to be carried out on the cement directly, on hardened cement paste or continuous on…

Alkalis should be present only in small quantities. Excess quantities of alkalis cause efflorescence and straining when used in concrete or mortar.

It makes the cement sound when present in small quantities. Excess of sulphur trioxide causes the cement to become unsound.

The correct quantity of magnesium oxide imparts hardness and colour to the cement. Soundness of cement is seriously affected, if it is present in excess quantity.

It provides colour, hardness and strength to the cement.

The quick-setting quality is imparted to the cement by alumina. Excess alumina reduces the strength of cement.

It contributes to the strength of cement due to the formation of dicalcium and tricalcium silicates. The excess presence of silica prolongs the setting time of cement but increases its strength.

It is the main constituent which contributes to the strength. Its proportion has to be properly maintained so as to make the cement sound and strong. Excess of lime makes the cement unsound and causes the cement to expand and disintegrate. On the other hand, if lime is deficient, the strength of the cement is…

The main ingredients in the manufacturing of cement are lime, silica, alumina and other oxides. The ingredients present in Ordinary Portland Cement are given in Table 6.1. The contributions by different ingredients are discussed below. Table 6.1 Ingredients of Portland cement