Concrete, Its Composition and Use: A Clear, Detailed, Complete Statement (Classic Reprint)

Lime, Puzzolans, and Natural Cement. All Rock Formed by Cement. The use of a cementing material for gluing hard, stony grains together to form larger masses of rocky substance is as old as the worlds history. Nature, in every rocky formation, has shown the way; in sandstones, limestones, slates, shales and conglomerates, the tiny grains have become skillfully cemented one upon another until massive, rocky solids, even mountains, have resulted. Man, keen to observe and analyze the whys and wherefores of all things, discovered the basis or principle of this accretion to be a chemical change, in which certain substances in solution, filtering through the loose grains, minute and great, of which the earths crust is so largely formed, have become deposited in crystalline form, interlocking the particles as in a grip of steel. Gypsum as an Example of a Crystalline Substance. Plaster of Paris is gypsum minus the water of crystallization. It is a white powder composed of the elements calcium, stdphur, and oxygen chemically combined. Gypsum has in addition a certain amount of water in combination to which it owes its solid, semiopaque appearance. On heating sufficiently, this combined water is given off as vapor and the white powder plaster of Paris remains. Now on mixing this powder with water again, it hardens and reassumes its crystalline structure. A ny gritty substance, admixed with this plaster paste, becomes locked in the structure. Here we have an example of a cementing process. The action of lime is very similar in fact this is the underlying principle of all cementitious action. A ny variation or apparent difference is a matter of modification or refinement, in order to improve upon the extent and uniformity of this crystallization. Portland cement, as it is known to-day, is the most perfected form of cementing materials the present final product of the evo
(Typographical errors above are due to OCR software and don't occur in the book.)