Indian Engineering Volume 40 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 Excerpt: ...that the concrete is to be thrown in full depth and the surface lightly smoothed. 7. Hydraulicity is the power possessed by hydraulic lime and cement of setting naturally under water. Pure lime can have this power conferred upon it by intimate mixture with puzznolama or powdered clay, ground to the fineness of very fine flour. All this is weli-known to Engineers, but somehow it is the rule on works rather than the exception to find the soorkhee made from first-class well-burnt bricks, and very gritty. Such soorkhee is inert. It possesses neither the power of rendering pure lime hydraulic; nor does it even possess the power of clean sand in assisting the hardening of the lime in unplastered thin walls, penetrable by the atmosphere. Soorkhee must either be burnt exactly to the right degree tor the lime employed, or it is better to use sand alone, and build slowly and allow the atmosphere to do its work. For absolutely fine lime the clay must be real clay, and not common brick earth, and the clay must be just burnt sufficiently to be no longer capable, when finely powdered, of forming a paste, or becoming sticky, with water. The more naturally nydraulic the lime, the greater the degree of burning necessary for the clay. Full knowledge is only to be attained by practice and-experience. 8. To employ the words of a good Civil Engineer: --Concrete has all the faults of ordinary building material and a few more. Material must be perfect, composition and mixing perfect, handling perfect. Should any one of these points be neglected, the resulting "concrete" will probably be no more useful than so much mud. To summarise: --1. Take care the lime or cement employed completely fills the interstices in the sand used, and a little over. 2. Allow extra for very fine...