The Canadian Standard CSA CAN3-A5.M83 allows the addition of up to 5% carbonate additions for Type 10, normal Portland cement, and this allowance has recently been extended to Type 30, high-early strength cement. The possibility of extending the carbonate additions to the other cement types, including those for sulfate resistance and moderate heat of hydration, has been discussed by the A5 Committee, and some concrete test data have been presented. However, the initial results did not include testing for the effects on sulfate resisting or heat of hydration properties. Therefore, this study was initiated.