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I I AET #93-1379 - Page 10 f . Overlay - Although this approach may have the lowest initial cost, this approach may not I be appropriate on any of the streets over the long term. Existing streets would continue to have frost/drainage problems, and reflection cracking would appear within the new I pavement. This approach would include continued higher maintenance cost, and would I not perform as well. The approach could be considered on Keithson Drive; although with the sags in the road, thicker bituminous overlay materials would be needed to - provide a more level surface in sag areas. I . Cold In-place Recycling - This approach may have limited results in the Bussard, Amble, I and Dunlap Street areas, as again frost/drainage problems would be expected to continue. I However, this approach may be appropriate for Keithson Drive since the subgrade already includes a granular borrow layer. .. . Roadway Reconstruction - If the budget allows, we recommend you consider I reconstructing Amble Drive, Bussard Court and Dunlap Street so that the subgrade frost/drainage characteristics can be improved. The subgrade preparation should include I placing a sand drainage layer. Because portions of the subgrade are reasonably stable, it should be possible to significantly improve subgrade performance with only a l' I minimum thickness layer. Where subgrade strength is poor, we recommend increasing this to 2', as subcuts to improve strength in the lower portion of the 3' subgrade zone I will already be needed; and improving the currently wet subgrade soils can be difficult, particularly when underlying soils are of poor quality. I RECOMMENDATIONS I Sube:rade Preparation/Reconstruction Areas I We recommend streets being reconstructed undergo sub grade preparation with a select granular {' layer at the top of subgrade. We recommend this layer be a minimum of l' thick. Therefore, I