Bond Strength between Sealed Bridge Decks and Concrete Overlays

The bond strength between portland cement overlays and bridge decks treated with high-molecular-weight methacrylate sealers is examined. The data universally suggest that sealers reduce the available bond strength. However, extra surface preparation techniques, such as light sandblasting of the sealed surface or broadcasting sand over the surface immediately after sealing [at approximately 1 kg/m2 (20 lb/100 ft2)], restore the strengths to 80 or 85 percent, respectively, of the unsealed surface. Service-level fatigue testing and loading well beyond the serviceability limit state do not adversely affect the bond strength so long as the sealed surface is treated before the application of the overlay. Therefore, to seal the existing cracks, bridge decks may be sealed if either of the recommended secondary surface preparation techniques is followed.

Download Full-text

Shrinkage in Ultra-High Performance Concrete Overlays on Concrete Bridge Decks

MATEC Web of Conferences ◽

10.1051/matecconf/201927107008 ◽

2019 ◽

Vol 271 ◽

pp. 07008

Author(s):

William Toledo ◽

Leticia Davila ◽

Ahmed Al-Basha ◽

Craig Newtson ◽

Brad Weldon

Keyword(s):

High Performance ◽

High Performance Concrete ◽

Bridge Decks ◽

Plastic State ◽

Early Age ◽

Concrete Bridge ◽

Ultra High Performance Concrete ◽

Concrete Overlays ◽

Concrete Bridge Decks ◽

Normal Strength

This paper investigates the shrinkage and thermal effects of an ultra-high performance concrete (UHPC) mixture proposed for use as an overlay material for concrete bridge decks. In this study, early-age and longer-term shrinkage tests were performed on the locally produced UHPC. Thermal and shrinkage effects in normal strength concrete slabs overlaid with UHPC were also observed. Early-age shrinkage testing showed that approximately 55% of the strain occurred in the plastic state and may not contribute to bond stresses since the elastic modulus of the UHPC should be small at such early ages. Thickness of the substrate and amount of reinforcing steel were important factors for shrinkage in the slabs. The thickest slab experienced greater shrinkage than thinner slabs. Comparing this slab to a thinner slab with the same reinforcement indicated that reinforcement ratio is more important than the area of steel.

Download Full-text

Ultra-High Performance Concrete Overlays for Concrete Bridge Decks

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/471/3/032007 ◽

2019 ◽

Vol 471 ◽

pp. 032007 ◽

Cited By ~ 1

Author(s):

Ahmed J. Al-Basha ◽

William K. Toledo ◽

Craig M. Newtson ◽

Brad D. Weldon

Keyword(s):

High Performance ◽

High Performance Concrete ◽

Bridge Decks ◽

Concrete Bridge ◽

Ultra High Performance Concrete ◽

Concrete Overlays ◽

Concrete Bridge Decks

Download Full-text

Thin Conductive Concrete Overlay for Bridge Deck Deicing and Anti-Icing

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1698-07 ◽

2000 ◽

Vol 1698 (1) ◽

pp. 45-53 ◽

Cited By ~ 22

Author(s):

Sherif A. Yehia ◽

Christopher Y. Tuan

Keyword(s):

Bridge Deck ◽

Bridge Decks ◽

Average Power ◽

Public Works ◽

Concrete Bridge ◽

Concrete Overlays ◽

Concrete Bridge Decks ◽

Ice Accumulation ◽

Concrete Mix ◽

University Of Nebraska Lincoln

Concrete bridge decks are prone to ice accumulation. Bridge decks freeze before the roads approaching them freeze, making wintry highway travel treacherous. Road salts and deicing chemicals are effective for ice removal but cause damage to concrete and corrosion of reinforcing steel in concrete bridge decks. The resulting rapid degradation of existing concrete pavements and bridge decks is a major concern to transportation and public-works officials. The use of insulation materials for ice control and electric or thermal heating for deicing have been attempted, with unsatisfactory results. Conductive concrete is a cementitious admixture containing electrically conductive components to attain high and stable electrical conductivity. Due to its electrical resistance and impedance, a thin conductive concrete overlay can generate enough heat to prevent ice formation on a bridge deck when connected to a power source. In 1998, Yehia and Tuan, at the University of Nebraska–Lincoln, developed a conductive concrete mix specifically for bridge deck deicing. In this application, a conductive concrete overlay is cast on the top of a bridge deck for deicing or anti-icing. The mechanical and physical properties of the conductive concrete mix after 28 days have met ASTM and AASHTO specifications. Two concrete slabs were constructed with a 9-cm (3.5-in.) conductive concrete overlay for conducting deicing experiments in the natural environment. Deicing and anti-icing experiments were conducted in five 1998 snowstorms. Average power of about 590 W/m2 (55 W/ft2) was generated by the conductive concrete overlays to prevent snow and ice accumulation.

Download Full-text