Historic references Roman concrete

caesarea earliest known example have used underwater roman concrete technology on such large scale.

vitruvius, writing around 25 bc in ten books on architecture, distinguished types of aggregate appropriate preparation of lime mortars. structural mortars, recommended pozzolana, volcanic sands sandlike beds of pozzuoli brownish-yellow-gray in color near naples , reddish-brown @ rome. vitruvius specifies ratio of 1 part lime 3 parts pozzolana cements used in buildings , 1:2 ratio of lime pulvis puteolanus underwater work, same ratio mixed today concrete used @ sea.

by middle of 1st century, principles of underwater construction in concrete known roman builders. city of caesarea earliest known example have made use of underwater roman concrete technology on such large scale.

rebuilding rome after fire in 64 ad, destroyed large portions of city, new building code nero consisted of largely brick-faced concrete. appears have encouraged development of brick , concrete industries.

example of opus caementicium on tomb on ancient appian way in rome. original covering has been removed.