Asphalt pavement cracking: analysis of extraordinary life cycle variability in eastern and northeastern Ontario

X-ray fluorescence detection of waste engine oil residue in asphalt and its effect on cracking in service

“…Since current specifications generally under-design the pavement for thermal cracking, LS-308 provides a beneficial way forward since it consistently penalises poor performers more than superior performers. Figure 2 provides the maximum grade loss after 3 days of conditioning at 2108C vs. the cracking severity in the 20 contracts (Hesp et al 2009a). The graph shows that superior performers lost less than 38C from their low-temperature grade while poor performers lost more than 38C.…”

“…Thermal stresses are able to relax in sol-type asphalts but are retained in gel-type asphalts, often leading to premature and excessive cracking. However, few field observations regarding this problem have ever been published (McLeod 1972, Hesp and Subramani 2009, Hesp et al 2009a, 2009b, Soleimani et al 2009). …”

“…There is little reason for concern when the specifications ensure that the buyer gets a quality product that meets certain minimum performance criteria. However, when such a system is absent or incomplete, the consequences can be far reaching and often costly (Leclerc and Paradis 2002, Andriescu et al 2004, Yee et al 2006, Hesp et al 2009a. Given the typical 25 -40-year life cycle of asphalt pavements, it often takes a long time and trained eyes for problems to be recognised, which means that significant damage can be done to an entire network before corrective action is taken.…”

“…Low-temperature thermal stress cracking in asphalt pavements has long been recognised as a major form of pavement distress, with frequent studies aimed at finding a solution to this persistent problem. While the Superpave w specifications have been implemented in large parts of North America, the problem of thermal cracking seems unrelenting, with regular reports of premature and/or excessive failures (Andriescu et al 2004, Yee et al 2006, Hesp et al 2009a.…”

“…We have recently investigated a large number of regular paving contracts and trial sections in Ontario (Table 1) with the aim of validating improved asphalt cement specifications for thermal cracking (Hesp and Subramani 2009, Hesp et al 2009a, 2009b, Soleimani et al 2009). The current AASHTO M320 specification failed to accurately predict performance in a set of 20 regular contracts, of which nine had cracked prematurely and excessively and 11 had performed according to expectation.…”