While the need for good natural aggregates for concrete is increasing the known supplies are becoming depleted in some parts of the country. At the same time the problem of disposing of waste concrete is increasing. Obviously it would be desirable to reclaim this concrete for use as concrete aggregate. A study has recently been made at the U. S. Army Engineer Waterways Experiment Station in Vicksburg, Mississippi to determine what quality of concrete can be made from aggregate manufactured by crushing old concrete. It was found that suitable concretes could be made, though with slightly different strengths and other properties than obtained with natural aggregates. The study concerned itself with aggregates made from two kinds of concrete: one made with a siliceous (chert) gravel and natural sand aggregate, and other with a limestone aggregate. These are representative of a large portion of the aggregates used in this country. Concretes were made of these reclaimed aggregates as well as with fresh unreclaimed aggregates using low-alkali Type II cement. The crushed concrete aggregate was used in two ways. First, both the coarse and fine crushed materials were used in the mixtures to make test specimens. Second, mixtures were made with only the coarse portion of the crushed concrete aggregate and with natural sand as the fine aggregate. The concretes were made at a water-cement ratio of .49, an air content of 6 and one-half percent, and a slump of two and one-half inches plus or minus one-half inch. Neither fine aggregate satisfied the grading requirements of the test method but they were used without modification. Laboratory specimens were evaluated for compressive strength, frost resistance, and linear coefficient of thermal expansion. The result was that the mixture that contained crushed concrete as well as coarse aggregate and natural sand as fine aggregate compressive strengths were lower than in the corresponding concrete made entirely with natural aggregates but there was in the recycled concrete a striking improvement in resistance to freezing and thawing.