sentences:  Recent scientific breakthroughs examining Roman concrete have been gathering media and industry attention.Because of its unusual durability, longevity and lessened environmental footprint, corporations and municipalities are starting to explore the use of Roman-style concrete in North America, replacing the coal fly ash with volcanic ash that has similar properties.Proponents claim that concrete made with volcanic ash can cost up to 60% less because it requires less cement, and that it has a smaller environmental footprint due to its lower cooking temperature and much longer lifespan.