Although the application of surface treatments on bridge decks is expected to positively impact bridge deck condition, the effectiveness of specific surface treatments on extending bridge deck life has not yet been quantified on Utah bridge decks. Therefore, the objectives of this research were to develop and analyze deterioration curves for bare concrete bridge decks and decks with specific treatments commonly used in Utah. The scope of this study was determined by the types and extent of electronically available data, including selected static inventory information; maintenance, rehabilitation, and reconstruction histories; and National Bridge Inventory (NBI) condition ratings for the bridge decks.

The results of the work show that the average diffusion coefficient for bridge decks with SIPMFs is approximately twice that of decks without SIPMFs and that, on average, each additional 0.5 in. of cover beyond 2.0 in. allows an extra 2 years for decks with SIPMFs and 5 years for decks without SIPMFs before a surface treatment must be placed to prevent excessive accumulation of chlorides. Although the data generated in this research are based on conditions typical of bridge decks in Utah, they clearly illustrate the effect of cover depth and the presence of SIPMFs.

This research suggests that epoxy-based surface treatments should be specified for concrete bridge decks when both a chloride barrier and improved skid resistance are desired. If a chloride barrier is all that is needed or desired, a silane surface treatment should be considered; silane treatments are less expensive and easier to apply than epoxy treatments. When a large amount of epoxy is to be mixed, automatic proportioning equipment that can precisely monitor and control the ratios of components should be employed.

Several evaluation techniques were employed to assess concrete bridge deck condition, including visual inspection, hammer sounding and chaining, dielectric measurements, ground-penetrating radar imaging, resistivity testing, half-cell potential testing, and chloride concentration testing. The condition assessment testing confirmed that chloride-induced corrosion of reinforcing steel is the primary mechanism of deck deterioration and that inadequate cover over the upper steel mat facilitated accelerated corrosion damage in many instances. The bridge deck condition analyses produced from the results of non-destructive testing were compared to the visual inspection ratings assigned to each deck by UDOT.

Performance of protective coatings for bridge decks is evaluated. Applications to bridges on the New York State highway system from 1961 through 1967 included 1) surface overlays, 2) membranes between the structural slab and bituminous wearing course, and 3) surface sealants. Overlays and membranes consisted of epoxies, polyesters, polyurethanes, latexes, neoprenes, silicone rubbers, and asphalt cutbacks. Surface sealants included silicones, distillate oils, and linseed oil. None of the surface overlays lasted more than 2 to 3 yr. However, a flexible polyester resin with fiber glass has provided satisfactory service for 1-1/2 yr and will remain under observation. Leakage of box-girder bridges with a membrane was primarily due to shear-key construction (since modified), while the same materials applied to composite bridges were associated with leakage that could not be explained. A more comprehensive survey of membranes is planned. Silicone and distillate oil sealants on non-air-entrained concrete did not improve long-term durability. Air-entrained concrete, both with and without linseed oil treatment, showed no evidence of deterioration after 4 yr of exposure.

Given the need for increasingly cost-effective strategies for bridge deck maintenance, rehabilitation, and replacement, the Utah Department of Transportation (UDOT) initiated this research to ultimately develop a protocol offering guidance as to whether deteriorated bridge decks should be rehabilitated or replaced.