This image shows a drill core of volcanic ash-hydrated lime mortar from the ancient port of Baiae in Pozzuloi Bay. Yellowish inclusions are pumice, dark stony fragments are lava, gray areas consist of other volcanic crystalline materials, and white spots are lime. The inset is a scanning electron microscope image of the special Al-tobermorite crystals that are key to the superior quality of Roman seawater concrete. (Credit: Lawrence Berkeley National Laboratory and University of California at Berkeley)

read more at: http://www.sciencedaily.com/releases/2013/06/130604135409.htm

Roman technology was very advanced, their society collapsed due to political and social forces not for a lack of tools.