Simulation of HVS Tests using CalME

Calibration of Reflection Cracking and Permanent Deformation Models for Overlays Using Heavy Vehicle Simulator Tests

Dynatest International, Naverland 32, Clostrup, DK 2600, DENMARK, Email: pullidtz@dynatest.com
University of California, Davis, California, USA, Email: jtharvey@ucdavis.edu
University of California, Davis, California, USA, Email: rzwu@ucdavis.edu
University of California, Davis, California, USA, Email: djjones@ucdavis.edu
University of California, Berkeley, California, USA, Email: clm@newton.berkeley.edu

| Abstract | Introduction | Simulation of HVS Tests using CalME | Reflection Cracking Model |
| Simulation of Pavement Response | Permanent Deformation | Cracking | Conclusion | Acknowledgement & References |


Introduction

The goal of the study described in this paper was to evaluate the reflection cracking and rutting performance of asphalt mixes used in overlays for rehabilitating cracked asphalt concrete pavement in California. The main objective was to compare the performance of three overlays with mixes containing binders using California Department of Transportation’s (Caltrans’) MB specification (binders including recycled tire rubber and polymers blended at the refinery) against two control overlay mixes [dense-graded asphalt concrete (DGAC) and gap-graded rubberized asphalt concrete (RAC-G)]. These control overlays represent typical pavement structures currently used throughout California.

The project was divided into two phases. In the first phase six test sections were trafficked with the HVS to induce fatigue cracking on the asphalt concrete layer. The original pavement consisted of 77 to 88 mm of DGAC on a design thickness of 410 mm of aggregate base (AB) on a clay subgrade. The AB consisted of 100% recycled building waste material with a high percentage of crushed concrete. Reactive cement was found in the AB. In the second phase, selected overlay mixes were placed both on the trafficked and on the untrafficked sections, to evaluate:

  • Reflection cracking (expected failure mode) under HVS trafficking at moderate temperatures (≈ 20 °C), and
  • Rutting performance under HVS loading at high temperature (45-50 °C).

A laboratory study, primarily investigating the shear and fatigue properties of the mixes, was undertaken in parallel with the HVS study.
Both the reflection cracking experiment and the rutting experiment had one of each of the following overlays:

  1. Half-thickness (45 mm) MB4 gap-graded overlay with minimum 15 percent recycled tire rubber (referred to as “MB15” in this paper)
  2. Half-thickness rubberized asphalt concrete gap-graded (RAC-G) overlay
  3. Full-thickness (90 mm) DGAC overlay (split into two subsections in the analysis)
  4. Half-thickness MB4 gap-graded overlay
  5. Full-thickness MB4 gap-graded overlay
  6. Half-thickness MAC15TR gap-graded overlay with minimum 15 percent recycled tire rubber.

The test sections were instrumented with Multi Depth Deflectometers (MDDs) and thermocouples. At regular intervals during the HVS tests the resilient deflections were recorded at several depths using the MDDs and at the pavement surface using a Road Surface Deflectometer (RSD, similar to a Benkelman beam).

The permanent deformations were also recorded by the MDDs and the pavement profile was measured using a laser profilometer. Any distress at the surface of the pavement was recorded. During HVS testing the temperature was controlled using a climate chamber. Falling Weight Deflectometer (FWD) tests were carried out before and after the HVS tests. Details on the HVS and the instrumentation can be found in Harvey et al., 1998 and on the overall study in Jones et al, 2007.

<< Abstract