REALIZING STRUCTURAL DESIGN OBJECTIVES THROUGH MINIMIZATION OF CONSTRUCTION INDUCED CRACKING. SIXTH INTERNATIONAL CONFERENCE, STRUCTURAL DESIGN OF ASPHALT PAVEMENTS, VOLUME I, PROCEEDINGS, UNIVERSITY OF MICHIGAN, JULY 13-17, 1987, ANN ARBOR, MICHIGAN

The structural analysis of asphalt overlays is conventionally carried out for the inservice condition, over the traffic-serving life cycle of the pavement. However, there is a short period of time, during construction, when the overlay is quite different from its inservice condition but is not conventionally analyzed as a structure. This paper contends that the overlay's long-term behavior and performance may in fact be significantly affected by the construction procedures, aside from the usual requirements for density and voids. In other words, the overlay may not be as structurally sound when put into service as normally assumed. A theoretical analysis is first presented to compare stress, strain and displacement distributions for two representative overlays for both the construction and inservice situations. It is shown that there are major and significant differences. Then, the principle of relative rigidity is introduced and applied to the construction situation where a stiff compactor acts on a soft layer which has been placed on an underlying stiff layer. A coefficient of stability can be used to identify instabilities in this loaded system, and in turn to show that the critical interface for new overlays is at the top. This can result in the often observed roller cracking. It is contended that the conventional circular roller therefore creates a curvature incompatibility between it and the distorted surface of the new overlay because of the large relative difference in stiffness. An experimental investigation was carried out on mixes compacted with such conventional equipment and a new Asphalt Multi-Integrated Roller (AMIR) to verify this contention and to propose a new approach to compaction. The results showed roller cracking to be eliminated when the AMIR compactor was used, and maximum bending strengths of the overlay material to be 30 to 70 percent higher. These results, while preliminary, suggest that substantially better long term performance of overlays may be achieved by a new method of compaction.

• Corporate Authors:

  University of Michigan, Ann Arbor

  Department of Civil Engineering
  Ann Arbor, MI  United States  48109
• Authors:
  • Abd El Halim, A O
  • Phang, W A
  • Haas, R
• Publication Date: 1987

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 965-978
• Serial:
  • Publication of: Michigan University, Ann Arbor
  • Publisher: University of Michigan, Ann Arbor

Subject/Index Terms

• TRT Terms: Asphalt; Asphalt pavements; Compaction; Conferences; Construction management; Dislocation (Geology); Field studies; Overlays (Pavements); Pavement cracking; Rollers; Strain (Mechanics); Stresses; Structural design; Theory
• Old TRIS Terms: Asphalt multi-integrated roller; Field investigations; Strains
• Subject Areas: Construction; Design; Highways; Pavements; Vehicles and Equipment; I22: Design of Pavements, Railways and Guideways;

Filing Info

• Accession Number: 00485657
• Record Type: Publication
• Files: TRIS
• Created Date: Jul 31 1989 12:00AM