There’s a story in Technology Review about a Halifax, Nova
Scotia-based company called Carbon Sense Solutions that has
found a way to make precast concrete products CO2-sucking
vacuums. The interesting thing about concrete is that over
hundreds of years they absorb CO2, a natural process called
carbonation. The amount of absorption partially offsets the CO2
emissions that result from the calcination of limestone during
the manufacture of cement, which is a key active ingredient of
concrete. One problem, however, is that during the earlier
stages of carbonation the outer two or three millimetres of the
concrete forms a hardened crust that significantly slows down
CO2 absorption. What Carbon Sense claims to have done is packed
hundreds of years of carbonation into as little as one hour,
using a curing process that consumes dramatically less energy
than conventional heat/steam curing (see presentation here). In
fact, compared to steam curing, company CEO Robert Niven says
his approach — building on 40 years of r