Iowa Department of Transportation
Iowa Highway Research Board
Peter Taylorptaylor@iastate.edu email >
Director, CP Tech Center
Kejin Wangkejinw@iastate.edu email >
PCC Engineer, CP Tech Center
About the research
The main factors negatively impacting concrete durability in Iowa are governed by moisture saturation and deleterious chloride ion reactions from deicing salts. Penetrating sealers are a class of materials that show promise for increasing concrete durability by reducing moisture and chloride ion penetration. Specifically, extending time to critical saturation reduces freeze-thaw exposure conditions, and limiting chloride ingress reduces the potential for oxychloride formation.
Numerous products exist in the sealer marketplace with a range of performance claims. Sealers can be categorized based on their chemical structure, functional type, amount of active chemical, carrier solution, and action mechanism, and they vary widely in performance. In addition, the parameters to define satisfactory performance are not agreed upon.
Although penetrating sealers show great promise for improving concrete durability, significant questions need to be answered before departments of transportation (DOTs) and other concrete pavement owners can be assured of a positive cost-benefit. Lack of clear performance guidelines hinder potential beneficial use given that design engineers, contractors, and owner agencies are unable to evaluate or compare performance of the available products.
The researchers reviewed a number of test methods for assessing penetrating sealants using a wide range of available products under several failure modes. Guidance was developed on how the action of the sealant should be tied to the potential failure mechanism, and which tests should be conducted on new products to ensure that they meet the needs.
This guidance can be used by agencies when reviewing the products available to them for a range of applications.