SPEC WRITER NOTES: Use following Article only if SELECT SUBBASE is specified. If Subbase is selected, delete the phrase (where required). SELECT SUBBASE (WHERE REQUIRED) Mixing: Proportion select subbase by weight or by volume in quantities so final approved jobmixed formula gradation, liquid limit, and plasticity index requirements will be met after subbase course has been placed and compacted. Add water in approved quantities, measured by weight or volume, to produce uniform blend. Placing: Place mixed material on prepared subgrade in uniform layer to required contour and grades, to maximum 200 mm (8 inches) loose depth that, when compacted, will produce layer of required thickness. When required compacted thickness exceeds 150 mm (6 inches), place subbase material in equal thickness layers. Remove unsatisfactory areas and replace with satisfactory mixture, or mix material in placement area. Adding thin layers of material to top in order to meet grade will not be permitted. When subbase elevation is 13 mm (1/2 inch) or more below grade, excavate top layer and replace with new material to minimum 75 mm (3 inches) compacted thickness. Compaction: Perform compaction with approved hand or mechanical equipment well suited to material being compacted. Moisten or aerate material as required to provide moisture content that will readily facilitate obtaining specified compaction with equipment used. Compact each subbase to minimum 95 percent or 100 percent of maximum density as specified by AASHTO T180 or AASHTO T99, respectively. Tolerances: Test completed subbase for grade and cross section with straight edge. Surface Variation: Maximum 10 mm (3/8 inch) each layer. Variation from Indicated Thickness: Maximum 13 mm (1/2 inch). Protection:
SPEC WRITER NOTES: Use following Article only if SELECT SUBBASE is specified. If Subbase is selected, delete the phrase (where required). SELECT SUBBASE (WHERE REQUIRED) Mixing: Proportion select subbase by weight or by volume in quantities so final approved jobmixed formula gradation, liquid limit, and plasticity index requirements will be met after subbase course has been placed and compacted. Add water in approved quantities, measured by weight or volume, to produce uniform blend. Placing: Place mixed material on prepared subgrade in uniform layer to required contour and grades, to maximum 200 mm (8 inches) loose depth that, when compacted, will produce layer of required thickness. When required compacted thickness exceeds 150 mm (6 inches), place subbase material in equal thickness layers. Remove unsatisfactory areas and replace with satisfactory mixture, or mix material in placement area. Adding thin layers of material to top in order to meet grade will not be permitted. When subbase elevation is 13 mm (1/2 inch) or more below grade, excavate top layer and replace with new material to minimum 75 mm (3 inches) compacted thickness. Compaction: Perform compaction with approved hand or mechanical equipment well suited to material being compacted. Moisten or aerate material as required to provide moisture content that will readily facilitate obtaining specified compaction with equipment used. Compact each subbase to minimum 95 percent or 100 percent of maximum density as specified by AASHTO T180 or AASHTO T99, respectively. Tolerances: Test completed subbase for grade and cross section with straight edge. Surface Variation: Maximum 10 mm (3/8 inch) each layer. Variation from Indicated Thickness: Maximum 13 mm (1/2 inch). Protection:
VA%20NCA%2032%2005%2023.docx