Rehabilitation of asphalt concrete layers of road pavements using HIR technologies enables effective elimination of surface defects (rutting, cracking, raveling, bleeding (flushing)) including defects caused by the non-conformity of asphalt concrete to the standard specifications. Due to the economical and ecological advantages, HIR technologies belong to the present-day effective alternative methods of rehabilitation of asphalt concrete pavements.
In Ukraine, HIR technologies were first applied on intermediate repair works on an area of the international road I-01 “Kyiv-Chernihiv-Novyye Yarylovichi” in the 2013. Now, HIR technologies have been applied on repair works on numerical objects including areas on such state motor roads as I-01, I-06, N-09, R-10, R-67.
The presented paper analyzes the results of monitoring of materials and technologies which was aimed on HIR performance investigation supported by State Road Agency of Ukraine (Ukravtodor) throughout 2014-2018.
The results of monitoring of HIR technologies including laboratory evaluation of materials and also field testing of the rehabilitated pavements led to the conclusions fitted by the world-wide experience on implementation of HIR technologies.
1. Being applied to the structurally sound pavements, HIR provides effective elimination of surface defects of flexible pavement to a depth of (50-60) mm including defects caused by the non-conformity of asphalt concrete to the standard specifications. However, HIR is not suitable for existing asphalt pavements which have too much variation in asphalt concrete composition and thickness within the project limits.
2. The efficiency of asphalt pavement rehabilitation using HIR technologies largely depends on precise engineering consideration which determines the efficiency of preparatory (repair) works including some special works such as:
– correction of cracks in case of cracking that extends below the depth of hot recycling;
– re-compaction of an unbound base layer(s) in case of the insufficient compaction causing “alligatored” network-like cracking of asphalt pavement.
3. Proper technical and working conditions of the rehabilitated pavement during the nominal life cycle could be maintained by overlaying the surface treatment using bituminous emulsion materials or by single-pass overlaying a new hot-mixed asphalt concrete layer.
Investigations accomplished during the implementation of HIR technologies allow enhance quality of recycled materials and also promote the entire adaptation of HIR technologies to the Ukrainian standards.
Keywords: asphalt pavement rehabilitation, hot in-place recycling, recycled asphalt concrete, field testing, road pavement strength measurement, rutting measurement.
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