Chloride Systems

Our experience is that a one-year waiting period is not needed for concrete that is well made, well finished, of adequate strength, has undergone a short period of air drying, and has an effective air-void system. Concrete that does not meet these criteria is always vulnerable to scaling when it becomes saturated and freezes. De-icing chemicals increase that vulnerability and may lead to scaling in concrete that might otherwise have performed acceptably despite being marginally air-entrained or having surface defects caused by improper finishing. More

A passivating oxide layer protects embedded steel reinforcement from corrosion. Over time, however, chloride and carbonation can cause the passivating oxide layer to deteriorate, leaving rebar open to corrosion. One way to rehabilitate concrete that has been corroded by carbonation is to remove the contaminated concrete and expose the corroded rebar so corrosion can be removed. Another newer option stops corrosion by drawing chloride ions out of contaminated concrete and restoring the high pH level. This process can restore concrete in 10 days to 10 weeks, according to its developer. More

To improve the region’s surface water quality and avoid costly treatment plant upgrades, Madison Metropolitan Sewerage District is encouraging area businesses to reduce salt use. More