The influence of calcium carbonate on the properties of four non-plastic lime-stabilized soils was studied. The four soils span a range in mica content and sand content. It was found that carbonate generally increased unconfined compressive strength and secant modulus of elasticity when included as part of the lime stabilizing agent. This effect was most pronounced with soils with a large sand content and low mioa content. A calcium hydroxide-calcium carbonate weight ratio of 3 to 1 was most effective for the case where six percent additive was used. It is hypothesized that the presence of carbonate enhances pozzolanic activity in lime-stabilized non-plastic soils by increasing the solubility of siliceous minerals at high pH levels. / Master of Science