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1 <br /> JJMD Buildings Bobs Burger&Brew JN 09266 <br /> November 18, 2009 Page 10 <br /> stabilize soft, wet, or unstable areas. Refer to the General section for subsurface drainage <br /> r measures where pavements are close to the surface of the glacial till. To evaluate pavement <br /> subgrade strength, we recommend that a proof roll be completed with a loaded dump truck <br /> immediately before paving. In most instances where unstable subgrade conditions are <br /> encountered, an additional 12 inches of granular structural fill will stabilize the subgrade, except for • <br /> very soft areas where additional fill could be required. The subgrade should be evaluated by <br /> Geotech Consultants, Inc., after the site is stripped and cut to grade. Recommendations for the <br /> compaction of structural fill beneath pavements are given in the section entitled General <br /> Earthwork and Structural Fill. The performance of site pavements is directly related to the <br /> strength and stability of the underlying subgrade. <br /> • <br /> The pavement for lightly loaded traffic and parking areas should consist of 2 inches of asphalt <br /> concrete (AC) over 6 inches of crushed rock base (CRB) or 3 inches of asphalt-treated base (ATB). <br /> ' We recommend providing heavily loaded areas with 3 inches of AC over 8 inches of CRB or 4 <br /> inches of ATB. Heavily loaded areas are typically main driveways, dumpster sites, or areas with <br /> truck traffic. Increased maintenance and more frequent repairs should be expected if thinner <br /> pavement sections are used. <br /> The pavement section recommendations and guidelines presented in this report are based on our <br /> experience in the area and on what has been successful in similar situations. As with any <br /> pavements, some maintenance and repair of limited areas can be expected as the pavement ages. <br /> Cracks in the pavement should be sealed as soon as possible after they become evident, in order <br /> to reduce the potential for degradation of the subgrade from infiltration of surface water. For the <br /> same reason, it is also prudent to seal the surface of the pavement after it has been in use for <br /> several years. To provide for a design without the need for any maintenance or repair would be <br /> uneconomical. • <br /> GENERAL EARTHWORK AND STRUCTURAL FILL <br /> All building and pavement areas should be stripped of surface vegetation, topsoil, organic soil, and <br /> other deleterious material. The stripped or removed materials should not be mixed with any <br /> materials to be used as structural fill, but they could be used in non-structural areas, such as <br /> landscape beds. <br /> Structural fill is defined as any fill, including utility backfill, placed under, or close to, a building, <br /> behind permanent retaining or foundation walls, or in other areas where the underlying soil needs <br /> to support loads. All structural fill should be placed in horizontal lifts with a moisture content at, or <br /> near, the optimum moisture content. The optimum moisture content is that moisture content that <br /> results in the greatest compacted dry density. The moisture content of fill is very important and <br /> must be closely controlled during the filling and compaction process. • <br /> The allowable thickness of the fill lift will depend on the material type selected, the compaction <br /> equipment used, and the number of passes made to compact the lift. The loose lift thickness <br /> should not exceed 12 inches. We recommend testing the fill as it is placed. If the fill is not <br /> sufficiently compacted, it can be recompacted before another lift is placed. This eliminates the <br /> need to remove the fill to achieve the required compaction. The following table presents <br /> �. recommended relative compactions for structural fill: <br /> I <br /> GEOTECH CONSULTANTS,INC. <br />