Rut Resistant Asphalt Pavements
The author of this article examines the causes and potential cures of asphalt pavement rutting. He explains that rutting on the asphalt pavement surface commonly is the result of an unstable asphalt mix, heavy vehicle traffic, and high pavement temperatures. He notes that this type of rutting is often observed at intersections, bus stops, freeway off ramps, or under extreme loading situations on airport runways or dock loading facilities. He explains how an engineer can determine if rutting in the asphalt pavement surface is due to distress throughout the entire pavement structure or due to failure in the asphalt layer only. He suggests that asphalt mixes can be designed to resist rutting with the proper selection of materials, good construction practices, and use of appropriate mix design methods. Good compaction practices during construction will improve rut resistance by increasing the interlock of aggregate particles in the mix.
PERMANENT DEFORMATION RESPONSE OF ASPHALT AGGREGATE MIXES
This report describes the research conducted on permanent deformation of asphalt concrete mixes as part of the Strategic Highway Research Program (SHRP) Asphalt Research Program. Divided into three sections, the report addresses the following: the development of a series of accelerated performance tests to measure the permanent deformation response and a constitutive relationship to define it; validation of the binder properties included in the SHRP binder specification; and the use of the test methodology in an asphalt concrete mix design and analysis system.
Modelling Drought and Recovery in the Southern Murray‐Darling Basin
The prolonged drought from 2006–07 to 2008–09 in south-eastern Australia presented severe difficulties for dry-land and irrigation farmers in the southern Murray-Darling basin. A dynamic multi-regional computable general equilibrium model (TERMH2O) is used to estimate the economy-wide small region impacts during and after drought. Drought reduces real GDP in some small regions by up to 20 per cent. Irrigation water trading and farm factor movements alleviate losses. The drought results in an estimated 6000 jobs being lost across the southern basin. Depressed farm investment during drought results in farm capital not returning to baseline levels after drought. Consequently, job numbers in 2017–18 remain 1500 below forecast in the southern basin.