Florida State University, Tallahassee
Florida Department of Transportation
Admixtures, Compressive strength, Concrete pavements, Cracking, Flexural strength, Ground tires, Laboratory tests, Life cycle costing, Mix design, Shrinkage, Tires
The objectives of this study are to: (1) develop a revised formal mix design of the ground rubber concrete (GTR) paving concrete, with optimal selection of components based on established criteria of strength, workability, and sustainability; (2) design an experiment (considering factors such as air content, water cement ratio, etc.) for varying the amount of superfine or fine aggregate size GTR in trial mixes of rubber concrete; (3) establish pretreatment procedures for the GTR particles and any other component of the rubber concrete; (4) conduct laboratory tests, with the conventional pavement concrete mix as a control, to study in the rubber concrete mix, the following: workability, air content, compressive strength, flexural strength, stress-strain relationships, YoungÛªs modulus of elasticity, shrinkage crack, impact resistance, and the coefficient of thermal expansion; (5) select the GTR best percentage content of the mix; (6) document experience and observations regarding mixing of rubber concrete in the laboratory, in terms of air content, water cement ratio, and the GTRÛªs moisture content; (7) work with a paving concrete company and ready-mix plant as research partners to execute implementation of results from the laboratory experiments, in terms of the mix design and actually mixing at the ready plant; (8) identify and recommend methods for storing GTR at the ready mix plant and also methods for introducing the GTR into the ready-mix trucks; (9) perform a sustainability analysis of the GTR concrete, including a comparison with the conventional concrete mix, in terms of lifecycle costs; and (10) prepare a final comprehensive report documenting all results and recommendations in the form of specifications indicating range of mix parameters, strengths, shrinkage crack requirements, and coefficients of expansion.