Recycling

High quality aggregates for highway construction are in short supply in many parts of Minnesota. Although the current total supply is adequate, the distribution of sources results in localized shortages. In some areas, it is necessary to import high-quality aggregates from distant locations. Long haul distances can increase aggregate prices substantially, add significantly to the overall project cost, and require the expenditure of sizable amounts of energy. One available source of high-quality aggregate is existing portland cement concrete pavement currently in need of reconstruction. Re-using this aggregate would conserve natural resources, result in cost savings in areas experiencing aggregate shortages and conserve natural resources, result in cost savings in areas experiencing aggregate shortages, and conserve energy in the form off fuel savings when aggregates must be acquired from distant sources. A research study was undertaken to; Determine the feasibility of recycling portland cement concrete pavement; evaluate the new recycled pavement; determine the cost effectiveness of recycling versus conventional paving; and determine the amount of energy consumed and natural resources conserved. Economic and engineering factors led to the selection of a 16-mil (25.7 km.) segment of U.S. 59 from Worthington to Fulda in Southwestern Minnesota for :his study. The in place roadway which was constructed in 1955 and consisted of a 9-7-9 inch (23-18-23 cm.) thick, 24 foot (7.3 m) wide, non-reinforced "D"-cracked concrete pavement with soil shoulders was broken, salvaged, and crushed. Material passing the #4 sieve (0.187 in., 0.476 cm) was used for base stabilization and shoulder aggregate, and material retained on the #4 sieve but passing the 3/4 in. (1.905 cm) sieve was used] as the coarse aggregate for concrete paving. Pavement removal began May 15, 1980 and concrete paving was completed September 24. 1980.

The task force conducted research to determine the optimum size, configuration, cost, and placement of rest area recycle containers; effective signs; possible funding sources; partnership possibilities with counties and the private sector; the best ways to sort and haul recycled material; the feasibility of recycling at all rest areas versus at Class I rest areas only; and a myriad of other particulars in order to develop a complete set of recommendations with a detailed implementation plan. The task force surveyed recycling efforts of other state DOTs, including Iowa, Wisconsin, Michigan, Vermont, Washington, Oregon, and North Carolina to discover their experiences with recycling materials collected at rest areas.

This brochure was produced as part of report 2009-09, "Recycled Pavements Using Foamed Asphalt in Minnesota."

This brochure was produced as part of report 2009-09, "Recycled Pavements Using Foamed Asphalt in Minnesota."

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."

This is a project summary of Report 2010-09, "Incorporation of Recycled Asphalt Shingles in Hot-Mixed Asphalt Pavement Mixtures."

Full Depth Reclamation (FDR) is a particularly useful method for rehabilitating structurally failed pavements. City streets, once beyond their design life, tend to fail due to structural problems such as moisture damage in the base layer or alligator cracking. FDR is a relatively low-cost, energy saving method that is capable of solving pavement problems associated with the deeper layers of the base. It has been adopted as the preferred recycling technique in the USA and many other parts of the world. In addition, introducing an injected emulsion to the FDR materials further improves the overall pavement strength and resistance to moisture ingress. In this sense, FDR with injected emulsion is an ideal technique for rehabilitating or reconstructing low-volume roads that do not require a thick mat of hot mix asphalt (HMA), but could use some improvement of the pavement structure to resist moisture and improve strength.

This Technical Summary pertains to the LRRB-produced Report 2009-32, “Hydraulic and Mechanical Properties of Recycled Materials,” published October 2009.

This Technical Summary pertains to the LRRB-produced Report 2009-27, “Use of Fly Ash for Reconstruction of Bituminous Roads,” published August 2009.

This Technical Summary pertains to LRRB-produced Report 2018-33, “Field Investigation of Stabilized Full-Depth Reclamation (SFDR),” published November 2018.