The continuous increase in the environmental impacts of the cement industry is of great concern to the society as population increases. Several reports have established that high CO2 emission, resource consumption and high-energy consumption are the major environmental impacts of the cement industry. One of the prescribed means recommended to reduce these impacts is the incorporation of fly ash into cement as it is considered environmentally benign. We have compared Portland cement with cement containing 5-15%, 11-35% and 36-55% of fly ash. A p-value higher than the significant level obtained ratified the hypothesis of a lower environmental impact with higher percentage of fly ash.