Originally posted by Tacho
I will have to find out myself about mechanical properties.
Some patents (US 5.690.729, 5.650.562, 5.518.540) claim that using CO2, dense-phase CO2 or supercritical CO2 (!) diffusion does the job reacting with
the calcium hydroxide generated by setting. This carbonation also happens naturally and is a problem to reinforced concrete because the higher pH
leaves the steel rebars unprotected against corrosion. I have some samples under CO2 and some under carbonated water.
I thought of phosphoric acid as a neutralizer because it usually produces insoluble salts or even some cements. ZnO+H3PO4 is a well known dental
cement. H3PO3 + lime makes a solid mass, not very hard, but solid anyway.
Phosphoric acid does not seem to lower the mortar resistance substantially if diffused after setting, but I can only check it’s diffusion with an
indicator. Hence this thread.
Since phosphoric acid is more expensive to me than polyester resin, I am willing to pay more for a less resistant material that is not commercially
viable, but will suit my special needs. The idea is a laminated shell with many thin fiberglass/cement layers. Each layer has to be neutralized,
adding labor and increasing costs. Not something LaFarge would consider.
[Edited on 26-9-2006 by Tacho] |