Circular 10—Natural Light-weight Building-Block Materials of New Mexico

By T. D. Benjovsky and D. M. Clippinger, 1945, 3 pp.

Lifting of the restrictions on building has brought the U.S. to the verge of a tremendous building boom. New homes, factories, warehouses, stores, and garages that have been planned for months may now become realities, and people are eager to begin construction. Because there is an acute shortage of building materials all over the country, New Mexico builders, calling upon their ingenuity, are manufacturing building blocks from materials provided by nature within the state. These blocks, which are durable, permanent and economical building material, are made for the most part from NM's volcanic rocks. Pumice, pumicite, scoria, or a mixture of two of these is combined with sand, cement, and water and is molded into building blocks. These blocks are of many sizes and shapes, depending upon the equipment used and the demands of the trade. The manufacturing of building blocks from gravel or coal cinders is not new, but the use of scoria and pumice is comparatively recent.

A building constructed out of pumice or scoria concrete blocks is literally a house of glass. Pumice is a natural silicic glass which was produced by volcanism as a molten froth. This froth, upon cooling rapidly, trapped tiny gas bubbles that caused it to remain extremely porous and minutely vesicular in structure. The pumice is nearly white in color and very light in weight; one cubic yard of the naturally crushed aggregate weighs only about 900 pounds. Scoria, or volcanic cinder, is a natural basic glass. Like pumice, it was deposited by eruption upon the Earth's surface. However, the cellular construction is larger and the walls of the cells are thicker. The scoria is slightly heavier and in itself stronger than the pumice. The color varies from red to black.