Contractors in Colorado have been using intelliRock concrete maturity loggers in shotcrete for several years. In one instance in 2008, winter arrived and the contractor was concerned about construction speed and heating costs. The contractor developed a maturity calibration curve then place intelliRock maturity loggers along the retaining wall being built. Once the concrete was placed the wall was covered and the heaters were turned on.

In general, a typical Colorado winter spec requires the contractor to maintain the placement above 50 F for 7 days or until there's proof that the placement has achieved 75% of the required concrete strength. In this case, the contractor used intelliRock to determine that the placement achieved 75% strength well in advance of the turn-time on previous walls - and during this one it was snowing! The savings on the heating costs alone made the owner extremely happy, not to mention the time savings.

C-DOT has since added concrete maturity to its construction specifications under section 641. The 2009 revision can be found at http://www.dot.state.co.us/DesignSupport/Construction/Recently%20Issued%20Specs/2009-11-05/601641s.doc