A model for top-down reflection cracking in composite pavements

Title: A model for top-down reflection cracking in composite pavements
Author(s): K. Nesnas, M. Nunn
Paper category : conference
Book title: Fifth International RILEM Conference on Reflective Cracking in Pavements
Editor(s): C. Petit, I.L. Al-Qadi and A. Millien
Print-ISBN: 2-912143-47-0
e-ISBN: 2912143764
Publisher: RILEM Publications SARL
Publication year: 2004
Pages: 409 - 416
Total Pages: 8
Nb references: 3
Language: English

Abstract: Investigations of as-laid composite roads in the UK have demonstrated that reflection cracks generally initiate at the surface and propagate down to the existing crack in the underlying concrete layer rather than travel up from the crack. The asphalt surfacing is normally treated as a passive layer that responds to the thermal movements of the crack in the cement bound base. This approach will predict bottom-up cracking. This paper presents a new response model, which treats the cement bound and asphalt layers as a complete system and recognises that:
· The asphalt thermal expansion coefficient is much higher than that of concrete;
· Larger temperature changes occur in the asphalt surfacing;
· Age hardening results in asphalt close to the surface becoming the most brittle region of the asphalt.
This response model predicts top-down cracking and, furthermore, it predicts that bottom-up cracking from the existing crack will not normally occur. Field data is also presented to support these predictions.

Online publication: 2004-04-15
Publication type : full_text
Public price (Euros): 0.00