Ground tire rubber (GTR) as a component material in concrete mixtures for paving concrete.

Details

• Creators:
  Sobanjo, John O. ; Tawfiq, Kamal S. ; Twumasi-Boakye, Richard ; Inkoom, Sylvester ; Gibbs, Sheldon
• Corporate Creators:
  Florida State University. Dept. of Civil and Environmental Engineering ; Gibbs Group Engineers
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Concrete pavements
  • Crumb rubber
  • Workability
  • Laboratory tests
  • Modulus of elasticity
  • Compressive strength
  • Shrinkage
  • Thermal expansion
  • Ready mixed concrete
  • Mechanical properties
• Publication/ Report Number:
  BDV30 977-08
• Resource Type:
  Tech Report
• Geographical Coverage:
  Florida
• Corporate Publisher:
  Florida. Dept. of Transportation. Research Center
• Abstract:
  This research was done to investigate if the problems associated with flexibility and temperature sensitivity (expansion and ; contraction) in roadway concrete pavements can be addressed by replacing some of the fine or coarse aggregate component ; with crumb rubber, specifically, Ground Tire Rubber (GTR). The research also intended to find out the general effects of ; adding the GTR to the conventional pavement concrete, in terms of the mechanical properties and workability, requiring ; several laboratory tests to be conducted as part of the study. Finally, the research was required to evaluate the practical ; implementation at a ready mix plant, of the proposed use of GTR as a component in the concrete. It was found from the ; study that the modulus of elasticity of concrete is reduced when GTR is used in concrete, thus the pavement concrete ; becomes more flexible. Based on the results of the tests for the coefficient of thermal expansion (CTE), it was not ; conclusive from this study, that adding GTR will significantly affect the expansion and contraction in the concrete ; pavement. ; Many valuable findings from this study include the following: the optimal content for GTR for use as a component in the ; paving concrete mixture is 15% by weight of the fine aggregate; at a water/cementitious ratio of 0.44, concrete with GTR of ; 15% by weight of the fine aggregate, using water-reducing admixtures, can achieve a 28-Day compressive strength of about ; 3000 psi as well as reasonable values of the flexural strength and split tensile strength; slump was observed to typically ; decrease with addition of GTR but use of the water-reducer will eliminate this problem; the unit weight of the GTR ; concrete is less than that of the conventional concrete; air content will always increase with addition of GTR to the concrete ; but the use of a defoaming agent will reduce the foam and air content; GTR concrete has a non-brittle mode of failure in ; compression and flexure; examining GTR concrete under the Scanning Electron Microscope (SEM) indicated that there is ; good bonding between the rubber particles and the cement matrix in the concrete; pretreatment of GTR by simple washing ; and drying may improve the compressive strength of the GTR concrete; GTR concrete has very good plastic and dry ; shrinkage attributes, with the ability to resist shrinkage cracking; the ready mix plant operations will require dry-safe ; storage of the GTR, customized packaging (bag sizes or bag material) of the GTR for convenient batching, and a less ; duration for mixing before placement (when compared to the 90 minutes mixing duration allowed for conventional ; concrete); the GTR concrete can be used in the following applications: Class I pavement; sidewalks; curbs and inlets; or ; applications where the compressive strength of 3000 psi or less is adequate and also where shrinkage may be a problem.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28743/dot_28743_DS1.pdf
• File Type:
  [PDF - 9.10 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:a3f85064a6adacfe5863145b6b9d46dac7ad7142a8b14cff4c4b97cfd1cc2b42