I wrote about this more than years ago–How Roman concrete could significantly increase the longevity of church buildings. See Recreating Roman Concrete That Lasts 2,000 Years.
The fact that the Romans had a better formula for concrete than we have today is amazing:
U.S. Dept. of the Interior, Bureau of Reclamation tried to recreate Roman cement. See Taking Cues From the Ancient Romans.
Show me a building in the United States that will last as long as the Pantheon. See 10 FACTS ABOUT THE PANTHEON.