Pavement Preservation Journal - Spring 2013 - (Page 29)

MnROAD Studies Pavement Preservation By B. Worel, R. Olson, E. Johnson and T. Burnham P avement preservation has been a part of the MnROAD test facility since it first opened in 1994. Many conventional as well as innovative treatments have been evaluated both on concrete and asphalt pavements designed for high and low volume traffic. The Minnesota Road Research Project (MnROAD) is an accelerated pavement test track, owned and operated by the Minnesota DOT. MnROAD is located adjacent to I-94, 40 miles northwest of Minneapolis/St. Paul. It consists of two separate roadway segments containing 51 distinct test cells. Each test cell is approximately 500 ft. long and consists of different combinations of surface materials (asphalt, concrete, pervious asphalt and concrete, aggregate), aggregate bases and subgrades as well as variations in structural design and drainage features. MnROAD is located in a wet-freeze zone, and over the years researchers have been able to study new construction, rehabilitation and preservation treatments as each test cell deteriorates. The two MnROAD road segments are: • A 3.5-mile, two-lane Interstate mainline carrying “live” I-94 traffic, averaging 26,500 vehicles per day with 13 percent trucks for the westbound lanes, or 750,000 flexible and 1 million rigid Equivalent Single Axle Loads (ESALs) per year, and • A 2 1/2-mile, two-lane closed-loop low-volume road (LVR). Traffic on the LVR is restricted to a MnROAD 18-wheel, five-axle tractor/trailer that averages 70 laps a day. Here are some of the significant findings from MnROAD related to pavement preservation: • Micro surfacing. MnROAD demonstrated the effectiveness MnROAD research is unique in that facility includes a closed test track but also a long section of I-94 open to public traffic of traditional and flexible micro surfacing during the course of four maintenance projects between 1999 and 2006. The benefits of different crack repair techniques prior to micro surfacing were studied during the major study effort in 2003 that focused on restoring ride quality. In 2003, a matrix of 12 test cells received crack re-sealing, leveling of cupped transverse cracks, filling of rutted wheel paths, and control treatments. MnROAD learned multiple applications (crack repair with two lifts) provide the longest effect on ride, but costs need to be taken into account. Flexible micro surfacing uses an asphalt binder that is rigid enough for rut filling but is also flexible enough to inhibit low-temperature cracking. In a 2006 MnROAD study four LVR cells were filled with flexible micro surfacing. The treatments showed promising results for reflective cracking and rut filling. These results encouraged a 2012 micro surfacing project utilizing high-polymer modified emulsion on an interstate test cell. Using a softer base asphalt (PG34) should enhance the performance of micro surfacing in the northern climate states. • Chip seals. A pooled-fund study (TPF-5(153))—involving the Minnesota Local Road Research Board, Maryland, Minnesota, Ohio, Texas and Wisconsin—is underway to understand how pavement preservation improves the performance of the existing asphalt pavements relative to aging, to help determine the optimal timing for the application of these treatments. Surface treatments are being applied to successive subsections throughout the pavement life (from immediately behind the paver to successive years). Spring 2013 pavement preservation journal 29

Table of Contents for the Digital Edition of Pavement Preservation Journal - Spring 2013

President’s Message
MAP-21: Pathway to Preservation at the Federal Funding Level
Cold-in-Place Recycling, Fiber Membrane and Seal Preserves Desert Highway
NCPP: New Online Tool Helps Measure Road Network Health
NCAT UPDATE: Axle Loads, Mileage Begin to Accumulate on NCAT Tests
NEPPP: Ribbon Cuttings Shine Spotlight on New Hampshire Pavement Preservation
TPPC: Micro Surfacing Training Offered at Texas Center
MnROAD Studies Pavement Preservation
Enlist News Media in Battle for Pavement Preservation
HIR Solves Cost Challenge to Runway Reconstruction
Shale Gas Boom Drives Town’s Bridge Renovation
Optimum Time for Slurry Seal Depends on Original Build Dat
Index of Advertisers

Pavement Preservation Journal - Spring 2013