Investigation of Concrete Aggregate and Riprap Stone for the Rend Lake Reservoir, St. Louis District

摘要

Five materials were tested for suitability for use as riprap stone; four materials were crushed and graded into 11/2-3 in., 3/4-11/2 in., and No. 4-3/4 in. size groups and tested for suitab ility for use as a concrete coarse aggregate; and three natural sands were tested for suitability for use as concrete fine aggregate with or without addition of small size fractions from an admixture and which was tested for suitability for this use. The results of the tests indicate that the materials were all essentially satisfactory for the purposes for which they were tested. However, the use of the aggregates in concrete would necessitate a low alkali cement being specified, and the shaly fractions of the stone could become concentrated enough in some samples to have an adverse effect upon the ability of the riprap stone or coarse aggregate to withstand severe weathering. (Author)