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.
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."
The need for new rehabilitation designs is very important as the funding for both maintenance and construction projects becomes increasingly difficult to obtain. The design thickness of a bituminous overlay on a PCC pavement has often been a matter of the past experience of individual engineers who have to make these recommendations. This special study was undertaken to gather data on three different thicknesses of bituminous overlays on cracked PCC pavement. This study will also provide additional data on the effects of cracking PCC pavement. It is anticipated that data from this study will provide the Design Engineer with information that will be helpful in selecting the thickness of bituminous overlay and specifications for pavement cracking. This study will continue for a minimum period of 5 years.
This review was part of ongoing research to determine how Bituminous over Concrete (BOC) pavement cracks, and how to reduce or eliminate cracking of the Hot Mix Asphalt (HMA) overlay
This specification includes the requirements for the construction of concrete flatwork including pavements, curb and gutter, sidewalks, driveways, and aprons. When using these specifications, designers need to pick one or more of the following as additional bid items for additional quality improvements: concrete field testing, smoothness, maturity testing for strength, and enhanced aggregate qualities. Also the designer needs to decide which testing rate will be used on a project from either Table 5 or 6 of these specifications.
