Agenda - Council - 10/26/2021 - Laserfiche WebLink

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above its optimum moisture content. The upper 3 feet of fill and backfill should be compacted to a minimum of 100 percent of its standard Proctor maximum dry density. Full Depth Reclamation For "Full Depth Reclamation" areas there may be instances where the recommended aggregate base thickness exceeds the existing aggregate base thickness. The preferred method of pavement repair would be to reclaim the existing bituminous, subcut the subgrade, replace the reclaim and add additional aggregate base as needed then construct the bituminous pavement. Subcutting the subgrade may not be feasible or cost effective. As an alternate it may be possible to use a thicker bituminous pavement along with the existing aggregate base or possibly subcutting some of the exiting aggregate base. Using MN/DOT granular equivalencies, one (1) inch of bituminous is equivalent to 2.25 inches of MN/DOT aggregate base. R-Values Laboratory tests to determine the soils Hveem Stabilometer R-Value (R-Value) was beyond the scope of this project. Information provided in the State of Minnesota Department of Transportation, Geotechnical & Pavement Manual, Part II, indicates that R-Values for granular materials meeting the ASTM Classification SM, SP-SM and/or SP can range from 30 to 70. In areas where the subgrade soils consist of silty sand (SM) it is our opinion that an R-Value of 30 can be used for pavement design. In areas where the subgrade soils consist of poorly graded sand (SP) or poorly graded sand with silt (SP-SM) it is our opinion that an R-Value of 50 can be used for pavement design. Recommended Pavement Section Thickness It should be noted that the pavement sections presented below are not absolutes. Depending on serviceability expectations, material availability, and cost, there could be circumstances under which alternative sections will be more practicable. Subgrade R-Value of 30 Based on an estimated R-value of 30 and a maximum of 50,000 ESAL's we recommend a pavement section consisting of a minimum of 4 inches of bituminous underlain by a minimum of 9 inches of Class 5 aggregate base. Subgrade R-Value of 50 Based on an estimated R-value of 50 and a maximum of 50,000 ESAL's we recommend a pavement section consisting of a minimum of 4 inches of bituminous underlain by a minimum of 6 inches of Class 5 aggregate base. 4.4 Materials We recommend aggregate base meeting MN/DOT specification 3138 for Class 5 aggregate base. We recommend the aggregate base be compacted to 100 percent of its maximum standard Proctor dry density. We recommend that the bituminous wear and base courses meet the requirement of MN/DOT specification 2360. We recommend the bituminous pavements be compacted to at least 92% of the maximum theoretical density. Pavement reconstruction could include installing concrete curb and gutter. We recommend specifying concrete that has a minimum 28-day compressive strength of 4,000 psi. We recommend specifying 5 to 8 percent entrained air for exposed concrete to provide resistance to freeze -thaw 11