Asphalt concrete

About: Asphalt concrete is a research topic. Over the lifetime, 9587 publications have been published within this topic receiving 93844 citations. The topic is also known as: blacktop & asphalt.

Hirsch model for estimating the modulus of asphalt concrete

Abstract: The purpose of this paper is to present a new, rational and effective model for estimating the modulus of asphalt concrete using binder modulus and volumetric composition. The model is based upon an existing version of the law of mixtures, called the Hirsch model, which combines series and parallel elements of phases. In applying the Hirsch model to asphalt concrete, the relative proportion of material in parallel arrangement, called the contact volume, is not constant but varies with time and temperature. Several versions of the Hirsch model were evaluated, including ones using mastic as the binder, and one in which the effect of film thickness on asphalt binder modulus was incorporated into the equation. The most effective model was the simplest, in which the modulus of the asphalt concrete is directly estimated from binder modulus, voids in mineral aggregate, and voids filled with asphalt binder. Models are presented for both dynamic complex shear modulus and dynamic complex extensional modulus. Semi-empirical equations are also presented for estimating phase angle in shear loading and in extensional loading. The proposed model was verified by comparing predicted modulus and phase angles to values reported in the literature for a range of mixtures.

Modeling of Asphalt Concrete

Abstract: Contributors Chapter 1. Modeling of Asphalt Concrete Part 1: Asphalt Rheology Chapter 2. Modeling of Asphalt Binder Rheology and Its Application to Modified Binders Part 2: Stiffness Characterization Chapter 3. Comprehensive Overview of the Stiffness Characterization of Asphalt Concrete Chapter 4. Complex Modulus Characterization of Asphalt Concrete Chapter 5. Complex Modulus from the Indirect Tension Test Chapter 6. Interrelationships among Asphalt Concrete Stiffnesses Part 3: Constitutive Models Chapter 7. VEPCD Modeling of Asphalt Concrete with Growing Damage Chapter 8. Unified Disturbed State Constitutive Modeling of Asphalt Concrete Chapter 9. DBN Law for the Thermo-Visco-Elasto-Plastic Behavior of Asphalt Concrete Part 4: Models for Rutting Chapter 10. Rutting Characterization of Asphalt Concrete Using Simple Shear Tests Chapter 11. Permanent Deformation Assessment for Asphalt Concrete Pavement and Mixture Design Part 5: Models for Fatigue Cracking and Moisture Damage Chapter 12. Micromechanics Modeling of Performance of Asphalt Concrete Based on Surface Energy Chapter 13. Field Evaluation of Moisture Damage in Asphalt Concrete Part 6: Models for Low-Temperature Cracking Chapter 14. Prediction of Thermal Cracking with TCMODEL Chapter 15. Low-Temperature Fracture in Asphalt Binders, Mastics, and Mixtures Index

Disk-shaped Compact Tension Test for Asphalt Concrete Fracture

Abstract: A disk-shaped compact tension (DC(T)) test has been developed as a practical method for obtaining the fracture energy of asphalt concrete. The main purpose of the development of this specimen geometry is the ability to test cylindrical cores obtained from in-place asphalt concrete pavements or gyratory-compacted specimens fabricated during the mixture design process. A suitable specimen geometry was developed using the ASTM E399 standard for compact tension testing of metals as a starting point. After finalizing the specimen geometry, a typical asphalt concrete surface mixture was tested at various temperatures and loading rates to evaluate the proposed DC(T) configuration. The variability of the fracture energy obtained from the DC(T) geometry was found to be comparable with the variability associated with other fracture tests for asphalt concrete. The ability of the test to detect changes in the fracture energy with the various testing conditions (temperature and loading rate) was the benchmark for determining the potential of using the DC(T) geometry. The test has the capability to capture the transition of asphalt concrete from a brittle material at low temperatures to a more ductile material at higher temperatures. Because testing was conducted on ungrooved specimens, special care was taken to quantify deviations of the crack path from the pure mode I crack path. An analysis of variance of test data revealed that the prototype DC(T) can detect statistical differences in fracture energy resulting for tests conducted across a useful range of test temperatures and loading rates. This specific analysis also indicated that fracture energy is not correlated to crack deviation angle. This paper also provides an overview of ongoing work integrating experimental results and observations with numerical analysis by means of a cohesive zone model tailored for asphalt concrete fracture behavior.