Multi-scale imaging, strength and permeability measurements: Understanding the durability of Roman marine concrete

Hot mixing: Mechanistic insights into the durability of ancient Roman concrete

“…1, D and E , and fig. S1) also show sulfur throughout the mortar, which, as proposed previously ( 38 ), could be due to primary sulfur originating from the components used to prepare the mortar, secondary sulfur that entered the binding matrix through the pores of the mortar, seen as rings, or a combination of these. While all of these considerations are possible, detailed elemental analysis (fig.…”

“…Raman mapping (fig. S2) demonstrates that the sulfur-bearing pore walls contain predominantly gypsum, thus precluding the use of calcium sulfoaluminate fibers as a filling agent in these samples ( 38 ). Despite centuries of exposure to environmental attack, however, the masonry wall remains well preserved around the perimeter of the archaeological site.…”

Revisiting Ancient Roman Cement: The Environmental-Friendly Cementitious Material Using Calcium Hydroxide-Sodium Sulfate-Calcined Clay

“…The creative idea of using CH and volcanic ash could promote the generation of the calcium aluminum silicate hydrate (C-A-S-H) gel and straẗlingite (C 2 ASH 8 ), which is beneficial to the compressive strength and durability. 3,4 However, it was completely replaced by ordinary Portland cement (OPC) due to the lack of early mechanical properties and the limited supplies of raw materials. 5 Meanwhile, with the widespread utilization of OPC, the high carbon footprint and energy consumption in the production process have become severe issues.…”

“…More than 2000 years ago, the ancient Romans began to use volcanic ash and lime to produce cementitious materials, some of which have been in service ever since. , It is well known that Roman cement was produced by a mixture of natural volcanic ash and slaked lime (CH). The creative idea of using CH and volcanic ash could promote the generation of the calcium aluminum silicate hydrate (C-A-S-H) gel and strätlingite (C 2 ASH 8 ), which is beneficial to the compressive strength and durability. , However, it was completely replaced by ordinary Portland cement (OPC) due to the lack of early mechanical properties and the limited supplies of raw materials . Meanwhile, with the widespread utilization of OPC, the high carbon footprint and energy consumption in the production process have become severe issues. − Despite the fact that 8% of the world’s global anthropogenic CO 2 emission stem from the cement industry, the demand for building materials has yet to peak, especially in developing countries .…”