Concrete absorbs water.

Make it salty in the MN winter and you’ve got trouble. Saltwater rapidly corrodes reinforcing steel, which is bad news for parking ramps, bridges and roads.

Cover your damp foundation with insulation and drywall and you’ve got a potential mold problem.

Here is a solution that seems to solve the problem: Hycrete. It is an additive to concrete that fills the molecular gaps in the concrete, making it hydrophobic. From their website:

The corrosion resistant basics of all Hycrete formulations are constant. When used in concrete, Hycrete provides two levels of protection.

Hycrete protects the reinforcing steel. Hycrete coats the steel surface with a monomolecular film. One end of the Hycrete molecule is polar by nature and attaches to other polar particles, such as iron or other metallic molecules.

Hycrete provides water proofing properties to the concrete. Hycrete is reactive. It reacts with metals in the water, metals in the concrete, and metals of the reinforcement. From the reaction, a precipitate is formed where one end of the molecule has a long hydrocarbon chain. Like oil repels water, this precipitate fills the capillaries of the concrete, repelling water and shutting down capillary absorption.

And from a Hycrete press release:

“… According to William McDonough, founding partner of McDonough & Partners and a leader in the sustainable development and green office movements, “The need for external membrane and coating systems is eliminated [with Hycrete]. Any time a process in construction can be avoided, more is accomplished with less, and savings through time and material are realized.””

Via Treehugger.