Section 10: Alternate Pavement Rehabilitation Options
Alternate pavement rehabilitation options are used to allow more competition on pavement rehabilitation projects when using specialty processes.
This section will provide information on alternate pavement rehabilitation options to:
- hot in-place recycling (HIR)
- ultrathin bonded hot mix wearing course (UBHMWC)
- thin bonded permeable friction course (TBPFC)
- reflective crack relief interlayer (RCRI)
Alternate Options to Hot In-Place Recycling
The purpose of hot in-place recycling (HIR) is to correct asphalt pavement surface distress such as surface cracking, roughness, or lack of skid resistance through recycling the existing pavement. HIR can be effective in correcting surface defects, as long as the defects are not caused by structural inadequacy of the pavement.
The Cutler HIR process involves recycling the existing asphalt surface layer by heating, scarifying and adding a recycling agent. The recycled material is placed on the roadway surface, a thin overlay of new hot mix is placed over the recycled layer and the entire pavement layer is compacted using conventional compaction equipment.
Alternate options are mill and overlay or surface recycling process also referred to as the Dustrol process. Mill and overlay involves milling one inch of the existing top layer and replacing it with two inches of new overlay. A high percentage of RAP should be allowed in the new two-inch overlay.
The Dustrol process is an alternate to the Cutler process. The Dustrol process is a surface recycling process. The Dustrol process involves heating and scarifying the top layer of asphaltic pavement (typically the top one inch), mixing a recycling agent. A new overlay is placed on top of the new recycled surface using standard paving operations.Anchor: #i1075281
Alternate Options to Ultrathin Bonded Hot Mix Wearing Course (UBHMWC)
The ultrathin bonded hot mix wearing course (UBHMWC) is used as a preventative maintenance treatment to restore skid resistance and improve ride quality.
The UBHMWC is an open-graded mix placed on polymer modified rapid setting emulsion tack coat. The mix is placed before the emulsion breaks using a specialty paver. Note: The paver must meet the requirements of the Special Specifications 3142.
The UBHMWC may also be used when there are restrictions on overlay thickness due to clearance requirements.
The alternate option to this process is placing an underseal (seal coat) plus a 3/4-inch thick PFC with two separate pieces of equipment.Anchor: #i1075462
Alternate Options to Thin Bonded PFC (TBPFC)
Placement of a thin bonded PFC (TBPFC) surface is intended to provide increased safety and better ride quality on a high speed roadway.
The conventional use of TBPFC involves a surface course placed on a sealed pavement surface. TBPFC is the PFC mix placed on a polymer-modified rapid setting emulsion tack coat before the emulsion breaks using a specialty paver.
The alternate option to this process is placing an underseal (seal coat) plus a PFC, with two separate pieces of equipment.Anchor: #i1075523
Alternate Options to Reflection Crack Relief Interlayer (RCRI)
The purpose of the reflection crack relief interlayer (RCRI) is to retard reflection cracks on asphalt concrete overlays located on top of jointed concrete pavements.
The RCRI is a fine mix that is designed for cracking resistance using the flexural beam fatigue. The mix is typically placed one-inch thick and should be covered with an adequate overlay thickness to provide adequate resistance to rutting.
An alternate option is the crack attenuating mix (CAM). The cracking resistance of the CAM will be evaluated using the overlay tester.