STP941

    Polymer-Modified Asphalt Properties Related to Asphalt Concrete Performance

    Published: Jan 1987


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    Abstract

    Mechanical properties of asphalts containing styrenic block copolymers and properties of dense-graded asphalt concrete produced from these binders are presented. Materials studied include unmodified AC-5 and AC-20 asphalts and AC-5 containing 3 and 6% styrenic block copolymers.

    Dynamic rheology of the binders was studied as a function of temperature and deformation rate. Complex viscosity of the polymer-modified asphalts exhibits less temperature susceptibility than that of control asphalts from 0°C (32°F) to 93°C (200°F) and slightly higher temperature susceptibility above 93°C (200°F). The modified asphalts are viscoelastic throughout the pavement operating temperature range with a significant elastic component. However, the unmodified asphalts are essentially nonelastic above 38°C (100°F).

    Increases in polymer content increase viscosity, ductility, toughness, tenacity, and elasticity of the materials tested. However, shear-thinning characteristics of the polymer-modified asphalts allow handling by familiar techniques at conventional temperatures. Asphalt concrete was evaluated by resilient modulus and indirect tension over a range of temperatures. Results indicate tensile modulus is lowered at low temperatures and raised at high temperatures by addition of the polymer.

    Keywords:

    styrene-butadiene-styrene block copolymers, rheology, mechanical properties, viscoelasticity, complex viscosity, resilient modulus of elasticity, indirect tensile strength, force ductility


    Author Information:

    Shuler, TS
    Senior research engineer, New Mexico Engineering Research Institute, University of New Mexico, Albuquerque, NM

    Collins, JH
    Research chemist and supervisor, Shell Development Co., Houston, TX

    Kirkpatrick, JP
    Research chemist and supervisor, Shell Development Co., Houston, TX


    Paper ID: STP18528S

    Committee/Subcommittee: D04.45

    DOI: 10.1520/STP18528S


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