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City of Arden Hills <br />Project B2204011 <br />June 23, 2022 <br />Page 7 <br /> <br /> <br />C. Recommendations <br /> <br />C.1. Design and Construction Discussion <br /> <br />C.1.a. Reuse of On-Site Soils <br />The soils encountered within the borings are suitable for reuse as engineered fill. Soils with organic <br />contents greater than 5 percent, if encountered, should not be reused as fill. This may result in the <br />importing of soils to re-establish subgrade elevations. <br /> <br />C.1.b. Pavement Reclamation/Mill and Overlay <br />Based on our soil borings and our pavement cores obtained for the project, we have provided <br />recommendations for rehabilitation methods based on the observed core conditions for which streets <br />we recommend the mill-and-overlay approach for rehabilitation. A review of the pavement surface <br />conditions and the suitability for mill-and-overlay was not included in our scope of services, and we <br />assume the City has selected these streets for possible mill-and-overlay rehabilitation due to their <br />surface condition. <br /> <br />Based on our observations of the recovered samples, recommendations for streets that were in poor <br />condition (i.e., disintegrating, stripping or based on depth of debonding) will be noted later in the report <br />for which streets we recommend the FDR approach for rehabilitation. Roads subjected to reclamation <br />will consist of between 4 to 6 inches of bituminous pavement over a variable aggregate base layer. We <br />recommend performing a 9-inch FDR without pre-milling. Based on the measurements from the borings, <br />this generally will avoid subgrade soils through much of the project area; in areas where subgrade may <br />be penetrated due to a thin aggregate base, it appears the underlying soils are generally clayey with <br />some areas that are granular in nature. Areas of clayey subgrade should not be incorporated into the <br />reclaim. Areas consisting of granular subgrade soils can be incorporated into the reclaim. Variation of <br />existing pavement depth and materials should be anticipated. <br /> <br />If reclamation is performed on this project, we recommend frequent sieve analyses, depth checks, <br />asphalt content tests, and other quality control/assurance tests to ensure the proper section with <br />materials meeting the project specifications. <br /> <br />The gradation requirements of MnDOT Specification 3138 (Aggregate for Surface and Base Courses) can <br />be used for the aggregate base. We also suggest that the contractor assume some contingency for