Fatigue Durability of Stabilized Recycled Aggregate Base Course Containing Fly Ash and Waste-Plastic Strip Reinforcement

The report presented herein describes a laboratory investigation to evaluate the performance of a cement-stabilized pavement base course material consisting of recycled concrete aggregate, ASTM Class C fly ash, and waste plastic (high-density polyethylene) strips obtained from post-consumer water and milk containers. The primary focus of the study was to systematically characterize the new composite base course under both static and dynamic (fatigue) loading conditions to gain some insights into the long-term durability of the material. To achieve these goals, a coordinated experimental program was undertaken that consisted of the following four Phases: (1) Phase I: Selection of initial mix-design, (2) Phase II: Instrumented split tensile test program, (3) Phase III: Static flexural test program, and (4) Phase IV: Flexural fatigue test program. Since a stabilized layer within a pavement structure is subjected to repeated tensile (flexural) stresses due to dynamic traffic loadings, the experimental program primarily involved material characterization under split tensile or flexural modes. The main objective of utilizing plastic strip reinforcement was to inhibit the propagation of tensile cracks, and thus improve the overall toughness and fatigue resistance of the material. The cement content in all mixes used in this study was either 4% or 8% by total dry weight of the mixture implying that at least 92% of the base course composite consisted of waste or recycled materials. It was found that a mixture containing only 4% cement, 4% fly ash, and 92% recycled aggregate (by weight) achieved a compressive strength of about 5 MPa (725 psi), a split tensile strength of about 0.75 MPa (109 psi), and a flexural strength of about 0.95 MPa (138 psi), indicating a moderately strong stabilized base course material. Flexural fatigue tests conducted on the same mixture reinforced with 1.25% (by weight) of recycled plastic strips (51 mm long and 6.3 mm wide) showed that the performance of the composite base course was comparable to or better than other traditional stabilized material used in pavement construction. Significant results from the repeated load test program include: (a) the relationship between the stress ratio and the number of cycles to failure (S-N curve), (b) the resilient modulus, (c) fatigue endurance limit, and (d) damage accumulation characteristics in the material due to cyclic loading. The study indicates that the new composite base course consisting primarily of waste products holds considerable promise as an alternative material for the construction and rehabilitation of highway pavements.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; Photos; References; Tables;
  • Pagination: 55p

Subject/Index Terms

Filing Info

  • Accession Number: 01531728
  • Record Type: Publication
  • Files: TRIS, ATRI, USDOT
  • Created Date: Jul 18 2014 2:10PM