Project: Woodland Park VII office building, fast drying concrete floors
Customer: Interactive Intelligence - Indianapolis, IN
Contractor: Duke Construction - Indianapolis, IN
Finisher: Lithko Contracting - Lebanon, IN
Project obstacles and solutions: In any concrete slab where floor coverings are adhered with a water-based adhesive, there is a danger that water vapor escaping the concrete will break down the adhesive and cause the covering to break loose, bubble or become a moisture source for mold and bacterial growth. This can cause delays in construction schedules waiting for the concrete to dry to an acceptable level. Many common flooring systems require a Moisture Vapor Emissions Rate (MVER) equal to or less than 5 lbs/1000 sq ft/24 hours at the time of flooring application for warranties to be valid.

The main floor of the Woodland Park VII building was used to test the relative humidity (RH) of floor slabs on grade using Aridus Rapid Drying Concrete and a spray on moisture barrier. One third of the main floor was poured with Aridus and one third was treated with the moisture barrier spray. These two test slabs were compared to a third control slab using conventional concrete without any drying agents. The concrete was poured at a depth of 4 inches with a 4,000 psi mix. The floor was poured on December 2014 and the building was yet to be closed up from outside humidity.

Duke Construction placed RH probes in the concrete and measured the internal humidity on regular intervals (click on the chart to the right.) Duke was looking for a RH below 80% before they would consider laying any flooring. Within two weeks, the Aridus had dropped to 84%, compared to the moisture barrier concrete at 97% and the conventional concrete at 96%. The Aridus concrete continued to drop just above the 80% barrier while the building was open.

At 49 days, the structure was closed off and was heated sporadically with propane heating units. The RH of the Aridus dropped below 80% within days of the building being closed even though the permanent heat and any conditioned air had yet to be turned on. At 84 days (12 weeks), the Aridus had a RH reading of 75%, well below Duke's threshold for laying any flooring. The spray on dryer had an RH of 98% and the conventional concrete had an RH of 99%. At that same time, the MVER was 1.8 for the Aridus concrete.

To see the results of the testing, click here.
For more information on Aridus, click here.