Evaluation of Thin Polymer Overlays for Bridge Decks

Project Details
STATE

MT

SOURCE

MT DOT

START DATE

01/22/20

END DATE

12/31/23

RESEARCHERS

Krauss, Paul D.; Hawkins, Kathleen A.

SPONSORS

Montana DOT

KEYWORDS

Bridge decks, Concrete overlays, Polymer concrete, Preservation, Skid resistance, Surface treating

Project description

Polymer overlays consist of polymer resins and aggregates and are used on bridge decks to extend service life by providing waterproofing and chloride penetration resistance and restoring surface friction. High friction surface treatments (HFSTs) are a specific type of polymer overlay intended to provide long-term skid resistance by using aggregates with increased abrasion resistance. This study investigates the performance of HFSTs in Montana to address Montana Department of Transportation concerns regarding their durability and costeffectiveness. The objective of this research was to assess the factors that influence the long-term friction resistance and durability of polymer overlays, particularly HFSTs, in Montana. The study included a literature review of recent studies on thin polymer overlays and bridge HFSTs, a survey of the experiences of select transportation agencies across North America with polymer overlays, a field investigation in which the condition of HFSTs on select bridge decks across Montana was monitored over a period of three years, and laboratory work to supplement the field investigation and its findings. The study found that the HFSTs investigated are generally of good quality, had adequate installation practices, and have provided at least 5 years of satisfactory performance. The HFSTs demonstrated sufficient bond and excellent electrical resistance after up to 5 years of service and adequate skid resistance after up to 8 years of service. Defects observed in the HFSTs included reflective cracking, often around prior deck patch perimeters, likely due to the use of patch materials with relatively poor thermal compatibility or high shrinkage; reflective transverse cracking in the HFSTs that appeared to increase with time; wear of the HFST particularly in the wheel paths of the driving lanes, in the form of surface aggregate fracturing and loss of aggregate; and minor loss of the HFSTs at the approach joints likely due to snowplow abrasion and traffic impact.
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