Portland Cement Concrete at www.japanese-home-gardens.com

Grout came into use as a normal development following the discovery of portland cement in 1824. When the aggregate particles of portland cement concrete were left out of a concrete mixture, the result was grout; it was used to fill joints of masonry or to fill uneven surfaces and corners before placing concrete.

(5) Portland cement concrete. This is made by mix-ng Portland cement, sand, stone or gravel, and water. Portland cement is produced by mixing together argil-aceous and calcareous materials (such as clay or shale md limestone), heating them to a high temperature, and ;rinding the resulting clinker to a fine powder. (6) Miscellaneous materials. These are blast furnace ilag, seashells, coral rock, caliche (in natural deposits), ind the residue of the spontaneous combustion of waste 'rom lignite coal mines. They are useful in road sur-acing because they do not soften when it rains or break eadily under wheel loads.

The most important modern uses of grout are to fill the joints in concrete dams and to seal and stabilize the foundations of all types of dams. Other uses of grout include the filling of small spaces between the base plate of heavy machinery and its concrete foundation, filling cavities behind tunnel linings, and filling voids in preplaced particles of coarse aggregate. The term "grout" also includes chemical formulations that do not contain portland cement. A chemical grout, which is used for the same purposes as neat cement grout, can fill voids that are too small to permit the entrance of portland cement particles.