The purpose of this project is to assess the potential for replacing cement at levels of up to 15% in concrete mixtures. Sustainability is currently an ongoing push, especially in the field of cement production, which accounts for roughly 7% of the world's CO2 emissions. By replacing cement with a finely ground limestone, significant reductions in CO2 emissions may be realized. This research compared three commercially available ordinary portland cements with portland limestone cements containing 10-15% of interground limestone. An additional comparison was made to assess the effect of replacing the cement with a finely ground limestone instead of intergrinding the materials. To assess the potential implications of replacing the cement with ground limestone, the following aspects were investigated: the early age reactions and hydration process, early age and long term mechanical properties, durability in the presence of water and deicing salts, and the shrinkage performance.