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Bremer Financial Corporation <br />Project B2008939 <br />November 17, 2020 <br />Page 13 <br /> <br /> <br />C.2.f. Pavement Subgrade Proofroll <br />After preparing the subgrade as described above and prior to the placement of the aggregate base, we <br />recommend proofrolling the subgrade soils with a fully loaded tandem-axle truck. We also recommend <br />having a geotechnical representative observe the proofroll. Areas that fail the proofroll likely indicate <br />soft or weak areas that will require additional soil correction work to support pavements. <br /> <br />The contractor should correct areas that display excessive yielding or rutting during the proofroll, as <br />determined by the geotechnical representative. Possible options for subgrade correction include <br />moisture conditioning and recompaction, subcutting and replacement with soil or crushed aggregate, <br />chemical stabilization and/or geotextiles. We recommend performing a second proofroll after the <br />aggregate base material is in place, and prior to placing bituminous or concrete pavement. <br /> <br />C.2.g. Engineered Fill Materials and Compaction <br />Table 5 below contains our recommendations for engineered fill materials. <br /> <br />Table 5. Engineered Fill Materials* <br />Locations To Be Used <br />Engineered Fill <br />Classification <br />Possible Soil <br />Type <br />Descriptions Gradation <br />Additional <br />Requirements <br />▪ Below foundations <br />▪ Below interior <br />slabs <br />Structural fill SP, SP-SM, SM, <br />SC, CL <br />100% passing 2-inch <br />sieve <br />< 2% Organic <br />Content (OC) <br />▪ Drainage layer <br />▪ Non-frost- <br />susceptible <br />▪ Free-draining <br />▪ Non-frost- <br />susceptible fill <br />GP, GW, SP, SW <br />100% passing 1-inch <br />sieve <br />< 50% passing #40 sieve <br />< 5% passing #200 sieve <br />< 2% OC <br />▪ Behind below- <br />grade walls, <br />beyond drainage <br />layer <br />▪ Fill more than <br />10 feet below slab <br />elevation <br />▪ Retained fill <br />▪ Deep Fill SP, SP-SM, SM <br />100% passing 3-inch <br />sieve <br />< 20% passing #200 <br />sieve <br />< 2% OC <br />Plasticity Index (PI) <br />< 4% <br />Pavements Pavement fill SP, SP-SM, SM, <br />SC, CL <br />100% passing 3-inch <br />sieve <br />< 2% OC <br />PI < 15% <br />Below landscaped <br />surfaces, where <br />subsidence is not a <br />concern <br />Non-structural <br />fill Any 100% passing 6-inch <br />sieve < 10% OC <br />*More select soils comprised of coarse sands with < 5% passing #200 sieve may be needed to accommodate work occurring in <br />periods of wet or freezing weather.