A pile-supported embankment constructed on TH 241 near St. Michael, MN was instrumented with 48 sensors, including strain gages on the piles and on the geogrid, as well as earth pressure cells and settlement systems near the base of the embankment. Pile supported embankments are relatively novel structures employed largely at bridge approaches and highway expansions where soft soils would otherwise lead to unacceptably large differential settlements. The structure typically consists of a number of capped piles, well-compacted gravel, and one or more layers of geogrid reinforcement above the piles. Analyses of the data suggest that the redistribution of the embankment load to the piles occurs within and above the so-called load transfer platform, a 1 m layer of geogrid reinforced gravel. Arching seemed to take place within the embankment, such that the stress at the top of the platform was concentrated above the piles.
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.
St. Louis County performed two HMA reconstructions on portions of County State Aid Highways during 2004 and 2005; CSAH 4 south of Biwabik, and CSAH 16 east of US Highway 53. The county saw differences in initial cracking performance and identified the two roads as potential research sections in 2005. Both projects were HMA reconstructions consisting of two 12-ft driving lanes with 6-ft shoulders. 24 in. of select granular modified (less than 7 percent passing the #200 sieve) was placed above the natural soil, followed by 6 in. of class 5 base material, and 5.5 in. of bituminous pavement. The bituminous pavement was constructed as 2.5 in. base lift, 1.5 in. binder lift, and 1.5 in. wear course lift. The recycled Asphalt Pavement (RAP) for the two projects all came from CSAH 16 millings. Bituminous mixtures were designed using Marshall MV criteria.
This study is a continuation of Report 2009-15, "Best Practices for RAP Use Based on Field Performance."
Micro-milling provides an innovative way to rehabilitate asphalt pavements. Micro-milling uses a milling drum with more teeth and a tighter lacing pattern to create a smoother surface than the traditional milling process (about 3 times the teeth than regular milling heads). The smoother surface provides a better surface for thin overlays, ultra-thin bonded wearing course (UTBWC), chip seals, and microsurfacing.
This Technical Summary pertains to Report 2023-31, “Evaluation of Slurry Spreaders and Plows (Underbody, Wing and Two-Way Reversible),” published August 2023.
Colored concrete can provide many benefits to pavement, such as improved aesthetics and safety. However, several recently constructed colored concrete pavements in Minnesota have experienced a considerable amount of early joint deterioration. Determining the cause for such deterioration is difficult, as there is very little knowledge in the literature on the performance of the material, especially in relation to its durability. Many different techniques have been used for obtaining colored concrete, such as granular pigments, acid dyes and stains, and dry shake powders. The various materials used to add color are all expected to influence the material properties of concrete differently.
This study resulted in Report 2014-26, "Investigation and Assessment of Colored Concrete Pavement," published in August 2014.
Thin bonded concrete overlays of existing asphalt pavements (BCOA), also known as “whitetoppings”, are becoming increasingly popular as an economical way to extend the life of an in-place pavement. While there had been several procedures developed in the past to structurally design this pavement rehabilitation option, the need for a more rational mechanistic-empirical based procedure still existed. Recognizing this gap in knowledge, the Minnesota Department of Transportation began in 1993 to construct various BCOA test sections designed to develop data for a comprehensive new design procedure for BCOA. By 2007, many other states in the U.S. were also interested in improved design procedures for BCOA. So in 2008, a 5-year long pooled fund research project was initiated and funded by 6 states, including Minnesota, Missouri, Mississippi, New York, Pennsylvania and Texas. By the completion of the project, the states of Iowa, Kansas, North Carolina and South Dakota had also joined the project.
The goal of this research is to investigate each agencies current design method to discover similarities and differences in the way each agency designs and builds roadways for both low and high volume roads. Each agency was given design specific inputs of common climate, traffic, and existing subgrade soil (from MnROAD) and was asked to develop a design based on current design practice/standards. This paper documented the differences in construction, materials, and expectations on performance to provide and will provide a bases for future agency discussion. The initial survey contained more information that could be covered in this paper. Future goals could include the additional information for other research topics, developing possible test sections, and again to provide a common point of discussion for future efforts. This work also builds off of the efforts started with the NVF34/Nord FOU concept at the 2007 Iceland workshop.
This is a project summary of the research that went into Report 2013-15, " Recycled Asphalt Pavement: Study of High-RAP Asphalt Mixtures on Minnesota County Roads."
