42 Times People Asked The Internet A Strange Question And Got An Answer That Was Even More Interesting

10. Why Can Some Roman Concrete Survive 2,000 Years In Seawater When Modern Marine Concrete Can Need Repairs Much Sooner?

Some Roman harbor structures have remained exposed to Mediterranean seawater for centuries, and some are still remarkably well preserved. Modern concrete used in marine structures can also last for many decades, but may require repairs as deterioration sets in. That Roman builders had no modern understanding of cement chemistry, yet some of their concrete developed remarkable long-term durability in seawater. What was actually different about the way this concrete was made that allowed it to last so long? Throwawayxdryx: They survive as ruins, modern concrete probably would as well Frustrated9876 : Modern concrete will also last centuries without being repaired, but structures in use cannot be left to deteriorate to that state or they cease being useful.