J_2024 05 09_West Orange Stormwater Management Plan

PSE&G Mav 17.2011 Page 12 for corrosion of below grade concrete. Also, several samples of the soils were subjected to pH testing. The results of these tests are attached on Plate 8. Sulfates were not detected to the method detection limit in any of the samples. Chlorides were detected in SBH-1 and SBH-2 at concentrations of 52.4 and 103 parts per million and not detected to the method detection limit in the remaining samples. The pH test results ranged from 4.7 to 7.4. Based on American Concrete Institute (AC1) 318 guidelines, sulfate levels of less than 1000 parts per million indicate a negligible exposure for corrosion of concrete and ACI recommends the use of Type I cement. However, United States Department of Agriculture (USDA) guidelines indicate sandy soils with a pH of <5.5 are considered to have a high risk of corrosion potential and soils with a pH of 5.5 to 6.5 are considered to have a moderate risk of corrosion potential for concrete. Therefore, it may be prudent to use Type H cement in the construction which would provide at least a moderate resistance to attack. Pavement Design Criteria: Immediately prior to pavement construction, all exposed subgrades should be recompacted to a dense and stable consistency, and the upper twelve inches of the subgrade soils should be recompacted to at least 95 percent of the maximum dry density as determined by ASTM D-1557 test procedure. Any subgrade materials that cannot be compacted to the required densities should be excavated to stable subgrade materials and replaced with granular controlled compacted fill. Following compaction, new pavements may be supported by the recompacted existing near surface silty sand fill soils or by controlled compacted granular fill. Pavement subgrades consisting of the silty sand fill materials would provide a "medium" subgrade support condition for pavements, with an estimated California Bearing Ratio (CBR) value of approximately seven percent. No traffic data was provided to us. We have assumed areas would be subjected to sporadic automobile and