Pervious Concrete Chemical Degradation by Calcium Chloride Deicer

Abstract

The pervious concrete layer in a permeable pavement system may be susceptible to chemical degradation by various deicers applied during winter weather events. In this research, the chemical impacts of calcium chloride on pervious concrete specimens made in the laboratory were studied and compared with specimens with a water-only control. The 20 specimens were made with limestone aggregate and ordinary Portland cement (OPC) and were similar in porosity. Either 200 mL of deicer at a 3% mass concentration or 200 mL of water were poured onto the top of the 100 mm diameter specimens once weekly for 17 weeks and allowed to partially air dry in the laboratory in between applications. Debris started to fall from the bottoms of the specimens with the calcium chloride applications about halfway into the testing period. Unconfined compressive strength tests performed after the deicer applications were completed show a substantial decrease in strength for the specimens that received the calcium chloride applications. It is recommended that calcium chloride deicers not be used on pervious concrete made with limestone aggregate and OPC.