Is it substantially better than modern concrete with seawater-proof reinforcement? Stainless steel rebar, fiberglass rebar, and basalt rebar all exist. The latter sounds quite promising if you believe its manufacturers’ claims.
(A major cause of failure of concrete near or in the sea is that the rebar corrodes and expands, cause the concrete to break.)
Re:Instant stone (just add water) (2018)
by ChuckMcM on Monday November 18, 2019 @12:12AM
(#21562070)
Yes it is substantially better because it grows in sea water. Which is to say that it is self healing with respect to erosion. They give examples of roman maritime concrete that is over 2000 years old and still functional. No existing concrete does this (hence the DARPA call for research topics).
It is also why a concrete hulled boat using this stuff would not suffer hull erosion like the existing cement fleet did during world war II and afterwards.
It isn't clear to me (but I've not found a good paper on Roman "maritime" concrete either :-)) how it interacts with barnacles and other marine life.
"There does seem to be one particular application in which the Romans had a formula we would like to rediscover: maritime concrete, exposed to seawater. Normally, concrete in a pier or harbor erodes over time, both due to the salts and other minerals in the seawater, and due to the abrasion of sand and silt. However, some Roman marine structures have survived for 2,000 years. Geologists studying Roman concrete have recently discovered (2017) that the particular concrete formula used in those structures has a beneficial interaction with seawater, creating new crystals within the cementing matrix that actually increase strength. DARPA just announced that “Unlocking the Secrets of Roman Concrete” is one of many topics for exploration under a research awards program."