AbstractsEarth & Environmental Science

"Definition:- Portland cement may be defined as the product obtained by finely pulverizing clinker produced by calcining to incipient fusion an intimate and properly proportioned mixture of argillaceous and calcareous materials with no additions subsequent to calcination excepting water and calcined or uncalcined gypsum. While a review of Portland cement analysis would show a wide variation in chemical composition, it must not be supposed that such latitude in proportioning the raw material really exists. If the resulting Portland cement is to be sound, normal setting, and of good strength it is imperative that the raw materials shall be correctly proportioned as to the balance between the silica and alumina on the one hand and the lime on the other. Cements from different mills often vary several percent from each other as to the silica, lime, and alumina, and yet one appears to be as good as the other. This variation in composition is due in part to addition of gypsum to, and the contamination by the coal ash of the clinker and also to the absorption of carbon dioxide from the air" – Introduction, p. 1.