If disposal of a material is an expense, one naturally thinks of ways to turn it into something useful. What better way could there be to dispose of materials that are otherwise useless, or nearly so, than ot form them into concrete, producing a structure or pavement? Interest has developed in using a variety of wastes in this way. Colored glass may be used as an exposed aggregate to impart deep hues with brilliance. Special colored glasses are manufactured for the purpose but waste glass is also available from member companies of the Glass Container Manufacturers Institute, who now operate 90 glass container redemption centers. A number of techniques are useful. One is to embed the dry aggregate into a freshly troweled surface, spray it with a retarder and later expose the aggregate by scrubbing and washing with water. Another is to make a special facing mix containing the aggregate and place it in the mold for a precast panel. In addition to reclaimed glass a variety of other waste materials including mine tailings, waste foundry sand, ocean bottom dredgings and garbage frit have been incorporated into experimental pressed concrete brick in a process that is now available for commercial use. Many other materials have also been tested for possible use in this process, alone or in combination, because most waste materials are not available everywhere and some can be obtained in only a few locations. What about salvaged plastics? Recent announcements have told of ground polyethylene scrap being used successfully as a partial replacement for sand in concrete. Compressive strengths equivalent to those of normal weight concrete are said to have been achieved with about a 109 to 15 percent saving in weight. More complete studies indicate that when from 20 to 40 percent of the sand volume in either normal weight or structural lightweight concrete is replaced by this kind of scrap, the 28 day compressive strength is lowered significantly. Furthermore, creep increases markedly with the substitution of plastic scrap for a portion of the fine aggregate.