NRRA: Developing Best Practices for Rehabilitation of Concrete with Hot Mix Asphalt (HMA) Overlays Related to Density and Reflective Cracking

Status:  Complete
Report Date:  10/07/2021


Asphalt overlays are commonly used to rehabilitate deteriorated Portland cement concrete (PCC) pavements. However, mechanically or thermally driven movements at joints and cracks in the underlying pavement usually lead to development of reflective cracks in the overlay. The formation and propagation of reflection cracking is controlled by the mechanical properties of the asphalt and the condition of the overlaid pavement. Current state of practice for asphalt overlay design is policy oriented and lacking an engineered design approach. There is need for establishing state of practice in design of overlays as well as for assessment of PCC pavement condition and recommending improvements to existing pavement prior to overlay construction. The objective of this study is to develop a simple decision tree-based tool for selecting suitable asphalt mixtures and overlay designs to prolong overlay lives by lowering reflective cracking and improving in-situ density. This research will leverage the current National Road Research Alliance (NRRA) effort of constructing, instrumenting, and monitoring 12 MnROAD test sections, laboratory performance tests on asphalt mixtures from the test sections, and past field performance data. The proposed tool incorporates field performance data, performance modelling, and life-cycle cost analysis to develop best practices for rehabilitation of PCC with asphalt overlays.

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