Roman Concrete and Mortar (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption Ancient Roman concrete consists of coarse chunks of volcanic tuff and brick bound together by a volcanic ash-lime mortar that resists microcracking, a key to its longevity and endurance. Credit (Photo by Roy Kaltschmidt, Berkeley Lab) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.