HYDRAULIC CEMENT.
The rapid hardening under water of the cement which from that property derives its name of “Hydraulic Cement,” has been, and indeed is still, a subject of discussion as to the true theory of such action. We find in the June number of the Chemical News a paragraph which must prove very interesting to manufacturers as well as to all who use and take an interest in that most useful of building materials to which the Architect and the Engineer are so deeply indebted.
“In order to test the truth of the different hypotheses made concerning this subject, A. Schulatschenko, seeing the impossibility of separating, from a mixture of silicates, each special combination thereof, repeated Fuch’s experiment, by separating the silica from 100 parts of pure soluble silicate of potassa, and, after mixing it with fifty parts of lime, and placing the mass under water, when it hardened rapidly. A similar mixture was submitted to a very high temperature, and in this case, also, a cement was made. As a third experiment, a similar mixture was heated till it was fused; after having been cooled and pulverized, the fused mass did not harden any more under water. Hence it follows that hardening does take place in cement made by the wet as well as dry process, and that the so-called over-burned cement is inactive, in consequence of its particles having suffered a physical change.”
IRON STORE-FRONTS, No. V.
By Wm. J. Fryer, Jr., with
Messrs. J. J. Jackson & Bros., New York.