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City of Arden Hills <br />Project B2502087 <br />June 13, 2025 <br />Page 16 <br />C.5. Karth Lake Park Trail <br />We understand that Karth Lake Park Trail is not anticipated to touch the subgrade and will be limited to <br />removal of existing bituminous pavement, placing additional aggregate base down and then repaving. <br />The following subsections provide general recommendations for this work. <br />C.5.a. Base Grade Proofroll <br />After preparing the aggregate base, we recommend proofrolling the aggregate base with a fully loaded <br />tandem-axle truck. We also recommend having a geotechnical representative observe the proofroll. <br />Areas that fail the proofroll likely indicate soft or weak areas that will require additional soil correction <br />work to support pavements. <br />The contractor should correct areas that display excessive yielding or rutting during the proofroll, as <br />determined by the geotechnical representative. If the aggregate base proofroll shows signs of distress, <br />possible options could be to correct the subgrade which could include moisture conditioning and <br />recompaction, subcutting and replacement with soil or crushed aggregate, chemical stabilization and/or <br />geotextiles. If subgrade corrections occur, we recommend performing a second proofroll after the aggregate <br />base material is in place (where aggregate base was removed), and prior to placing bituminous pavement. <br />C.5.b. Design Sections <br />Our scope of services for this project did not include laboratory tests on subgrade soils to determine an <br />R-value for pavement design. Based on our experience with similar _ soils anticipated at the pavement <br />subgrade elevation, we recommend pavement design assume an R-value of _. Note the contractor may <br />need to perform limited removal of unsuitable or less suitable soils to achieve this value. Table X provides <br />recommended pavement sections, based on the soils support and traffic loads. <br />Table 8. Proposed Bituminous Trail Pavement Section – Karth Lake Trail <br />Material <br />Thickness <br />(inches) Material Material Specification <br />Bituminous wear course 1 1/2 SPWEA240C MnDOT 2360 <br />Bituminous wear course 2 SPWEB230C MnDOT 2360 <br />Aggregate base 6* Class 5 or 6 MnDOT 2211 <br />Approved subgrade --- --- --- <br />*Could potentially incorporate residual apparent aggregate base on-site from existing section, depending on site observations.