https://blockchaining.org/tags/opus-caementicium/ Recent content in Opus Caementicium on Blockchaining.org Hugo en-us Sat, 08 Aug 2026 00:00:00 +0000 https://blockchaining.org/roman-concrete-in-museum-fragments-what-the-cross-section-actually-shows/ Sat, 08 Aug 2026 00:00:00 +0000 https://blockchaining.org/roman-concrete-in-museum-fragments-what-the-cross-section-actually-shows/ <p>Museum displays of Roman building material tend to be badly labelled and quickly walked past. A broken lump of wall behind glass with a card reading &ldquo;concrete, 2nd century AD&rdquo; gives a visitor nothing. Which is a shame, because the cut face of that lump contains most of the answer to why Roman structures are still standing.</p> <p>Here is what to look for when you find one.</p> <h2 id="the-wall-is-a-sandwich-and-the-pretty-part-is-the-formwork">The wall is a sandwich, and the pretty part is the formwork</h2> <p>The single most common misreading is treating the visible facing as the wall. It is not. Roman walls of this type consist of a thick core of mortar and rubble, faced on both sides with a thinner skin of stone or brick that served as permanent shuttering during construction and as a finished surface afterwards.</p>