Admixture modified concrete shows deviation both in physical and chemical properties, compared to that of an ordinary cement concrete. The properties of these supplementary additives influence the characteristics of concrete to a great extent. Many researchers have proposed strength relationships incorporating the properties of the mineral admixtures and their influence on hydration mechanism for effective proportioning of such mixes. The present study aims to exhibit the suitability of a non-dimensional strength-cementitious material-water relationship as proposed by Chowdhury and Basu for fly ash based concrete, on commercially available PPC. Results obtained in case of commercial PPC are found to be within tolerance limits of ±4 % and ±1% of that derived using the lower bound relations of fly ash concrete for 28 and 56 days respectively. Test results also indicate that better utilization of material strength is possible if 56 days strength is considered while proportioning concrete mixture with PPC.