Izevbekhai, Bernard I.

Storm-water runoff from the Woodbridge neighborhood of the City of Shoreview had previously been managed through culverts and other hydraulic structures. In adherence to the Clean Water Act, many watersheds instituted limits to the percentage of storm water that may be allowed into certain lakes and rivers. To minimize this run-off and the associated impacts and in accordance with the City’s sustainable design policy, the City of Shoreview built the Woodbridge neighborhood local roads using pervious concrete pavements in 2008. Pervious concrete pavements exhibit high hydraulic conductivity and high sound absorption coefficient in local or low volume roads. They also provide cost savings through the minimization of hydraulic structures.

The sound absorption test measures the sound absorptiveness of a pavement surface. The sound analyzed is not generated by the interaction of the rolling tire with pavement surface but by noise source above the impedance tube. During the test, the impedance tube is placed on the pavement surface and a set of sensitive microphones are attached to the pre-installed housing at the lower end of the tube. These microphones are also connected to an analyzer. The noise source sends the incident sound energy (white noise) to the surface and the incident and reflected waves are captured by the two microphones. Software analyzes the reflected waves and converts the data to the 3rd octave sound absorption coefficient at 315, 400, 500, 750, 1000, 1250 and 1650 Hertz. Thus, the sound absorption coefficients at each frequency are between one and zero, where a value of one would mean that all of the sound is being absorbed by the pavement surface.

Pervious pavement provides a solution for many highly developed urban areas where an excessive amount of contaminated water is diverted into storm and sewer systems and left untreated before entering natural water sources such as rivers and streams. By allowing water to flow through the pavement surface and infiltrate the underlying soil, pervious pavements can reduce the amount of this pollution. Test cells were constructed at MnROAD to be monitored for drainability to evaluate the possibility of using pervious pavements to mitigate this problem. Other important criteria influencing the performance of pervious concrete in pavements will also be monitored, including mechanical and structural properties, surface characteristics, noise, and durability. This document summarizes the research that went into Report 2011-23, "Pervious Concrete Test Cells on MnROAD Low-Volume Road.."

This study examines various new textures and monitors them over time with a litany of standard tests. In the process certain analytic initiatives are performed. This study was part of the basis for Report 2015-48, "Pavement Surface Characteristics Concrete New Construction (MnROAD Study)."

This paper discusses the construction and early performance of a pervious concrete test cell at the MnROAD facility. The cell is subjected to daily loading of an 80-Kip 5-axle semi-trailer, two times a day, four days a week and 102-Kip 5-axle semi-trailer twice a day, one day a week. Performance was evaluated by comparing Falling Weight Deflectometer (FWD) deflection basins to those of normal concrete pavements of similar thickness design. Stress-strain response of the pavement system was computed from dynamic strain gauge data. Temperatures and freeze-thaw cycles at various pavement depths where monitored. An in-situ method for measuring time rate of flow was developed. Petrographic analysis reveled differences in porosity between the surface and bottom layers as well as drying shrinkage cracking. Normal sanding and salting operations during the winter do not appear to have impacted the pore structure within the pervious concrete after three years of service. Spalling and raveling were prevalent at the tooled joints and occurred in sections where the surface could have prematurely dried due to overworking. The test cell driveway showed superficial wear near the joints after its first season in service. Large 12x12 ft rectangular block cracking was observed after 2 ½ years as well as reflective cracking propagated from joints of the surrounding curb. Critical parameters including time rate of flow, raveling, and cracking will continue to be monitored. This paper was submitted to the Transportation Research Board for the 2009 Annual Meeting.

This report documents study of the field performance of an inlay type thermoplastic pavement marking material along with the two-year-old bituminous pavement to which it was applied. Evaluation included physical performance of the product and the effect on overall durability of the pavement surface. The installation was performed in May, 2006 on a bituminous test cell at MnROAD’s Low Volume Road. 524 square feet of inlaid thermoplastic pavement marking material were installed on a surface of 4 in. Superpave hot mix asphalt, including one segment installed along 100 ft of left wheel path of a lane that received standard truck load configurations, and two crosswalks that received load configurations that varied by lane. During the period between May 16, 2006 and August 1, 2007 Cell 26 received 6,809 and 2,003 repetitions of the standard 80K and overloaded 102K truck configurations respectively. The installation was a decorative treatment, not a retrofit of longitudinal lines on the existing pavement. This paper was submitted to the Transportation Research Board for the 2009 Annual Meeting.

In Minnesota, concrete pavements are finished by dragging an inverted turf or a stiff-bristled broom longitudinally on the surface of freshly placed concrete pavements, right behind the paving machine. Prior to 1998, most concrete pavements were finished with a combination of the burlap-drag and transverse-tining. Subsequently those pavements were reconstructed and finished with current broom or turf drag. The study sought to ascertain if current texturing techniques resulted in higher wet weather accident events. A Minnesota Department of Transportation (Mn/DOT) study selected segments in the network where current texturing techniques replaced previous textures. Annual wet weather accidents data from the Mn/DOT database were analyzed. By examining annual wet weather accident counts, total accident counts and crash rates for a ten year period, current textures were compared to previous textures. The paper discusses how 3 statistical tools were used to compare wet weather accident data from previous texturing to data from current texturing. Statistical tools showed that current texturing practices did not cause increase in the annual wet weather accidents, crash rates as well as ratio of wet to dry weather accidents in the chosen test sections. This paper was submitted to the Transportation Research Board for the 2008 Annual Meeting.

 The Minnesota Department of Transportation (Mn/DOT) is currently evaluating a change from the Profile Index (PI) to the International Roughness Index (IRI) for smoothness specifications for portland cement concrete (PCC) pavements. This change has already occurred for bituminous pavements in Minnesota. The Mn/DOT Office of Materials, as well as paving contractors in Minnesota, is naturally concerned with the effects that this change will have on the quality of pavement surfaces and on the incentives paid for new pavement smoothness. The Office of Materials has funded an “implementation” project to compare the two smoothness statistics and to provide recommendations for implementing the new specification. This paper contains several analyses and comparisons of the relative effects of pavement features in design and construction with regard to the results of pavement surface smoothness and incentive computations. It also contains an analysis of segment length for incentive/disincentive calculations on PCC pavement projects. The information presented in this paper can be useful to those considering changing pavement smoothness specifications from profile index to international roughness index. This paper was submitted to the Transportation Research Board for the 2007 Annual Meeting.

The Minnesota Department of Transportation and many municipalities in Minnesota have built sidewalks city streets, low volume roads, boat ramps and parking lots with pervious concrete. Since 2005 when the first pervious concrete initiative was constructed at the MnROAD facility, three test cells have been constructed, monitored and maintained. Paradoxically, non pervious pavements are similar to pervious pavements in their requirements for drainability for durability. However pervious concrete requires that the voids should be connected and free of clogging agents for durability of conductive and acoustic properties. The effect of clogging and the characteristics of pervious concrete, clogged with various agents are examined. Desirable acoustic absorption and hydraulic conductivity are reduced when pervious concrete is clogged and may be restored with adequate maintenance practices.

 Some improvements made over the single laser equipped accelerometers often used in light weight profilers include the triple point laser (TriODs) and the line (Roline) laser. In the specifications for post-construction pavement smoothness acceptance of concrete pavements, a distinction is not made of the type of laser to be used. However preliminary research shows a consistent disparity between the TriODs generated roughness index and the line laser generated roughness index in most concrete textures. Moreover in certain longitudinal box car configurations including the quiet innovative diamond grind configurations, the two data sets are significantly different. Construction induced skewness and waviness as well as squirm phenomena trigger effective lateral traversing of these longitudinal textures, causing anomalous IRI when the single or triple laser is used. This anomalous observation is expatiated and possible remedies applicable to pavement construction specification enunciated. This paper was submitted to the Transportation Research Board for the January 2012 Annual Meeting.