Use of Lightweight Concrete for Reducing Cracks in Bridge Decks

Cracks in bridge decks can be due to many factors related to environmental effects, chemical reactions, and structural loads. Careful selection of materials and mixture proportions can minimize cracking to some degree. To reduce cracking, shrinkage must be reduced; however, cracking also depends on other factors such as modulus of elasticity, creep, tensile strength, and restraint. A low modulus of elasticity and high creep help to minimize cracking. Lightweight concrete (LWC) has a lower modulus of elasticity, higher inelastic strains, a lower coefficient of thermal expansion, a more continuous contact zone between the aggregate and the paste, and more water in the pores of aggregates for continued internal curing when compared to normal weight concrete. These properties tend to reduce cracking in the concrete and are highly desirable in bridge decks. The Virginia Department of Transportation (VDOT) has been successfully using LWC in bridge structures. In most of these bridges, the coarse aggregate has been lightweight and the fine aggregate normal weight natural sand. The purpose of this study was to investigate the effectiveness of LWC in reducing cracks in bridge decks. Seven bridges from six VDOT districts were included in the study. Three bridge decks each were constructed in 2012 and 2013, and one was constructed in 2014. The results showed that bridge decks with fewer cracks than were typical of decks constructed with normal weight aggregate over the past 20 years or no cracks can be constructed with LWC mixtures. The study recommends that LWC with a maximum cementitious content of 650 lb/yd³ be used in VDOT bridge deck concrete mixtures.

• 
• Summary URL:
  http://vtrc.virginiadot.org/PubDetails.aspx?PubNo=16-R14
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/30705
• Corporate Authors:

  Virginia Transportation Research Council

  Charlottesville, VA  United States 

  Virginia Department of Transportation

  Richmond, VA  United States 

  Federal Highway Administration

  400 North 8th Street
  Richmond, VA  United States  23219-4825
• Authors:
  • Nair, Harikrishnan
  • Ozyildirim, Celik
  • Sprinkel, Michael M
• Publication Date: 2016-4

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Figures; Photos; References; Tables;
• Pagination: 23p

Subject/Index Terms

• TRT Terms: Bridge decks; Cracking; Lightweight concrete; Shrinkage
• Geographic Terms: Virginia
• Subject Areas: Bridges and other structures; Design; Highways; Materials;

Filing Info

• Accession Number: 01596817
• Record Type: Publication
• Report/Paper Numbers: FHWA/VTRC 16-R14, VTRC 16-R14
• Contract Numbers: 103636
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Apr 22 2016 10:46AM