Macadam base course shall include the construction
of pavement base courses of macadam to the prescribed lines, grades,
and dimensions, at the prescribed locations, and in accordance with
the plans and specifications.
The crushed stone shall be two-and-one-half-inch size crushed stone, and the binder materials shall be screenings B. Both the crushed stone and screenings shall conform to the requirements therefor as set forth in Article II of this chapter.
A.
The subgrade shall be prepared as specified in Article X of this chapter, and shall be in a properly finished condition and not wet or frozen when the base course is about to be placed thereon. The crushed stone shall be spread on the subgrade in a layer of the proper depth, and shall be compacted with three-wheel power-driven rollers having a load of not less than 330 pounds per linear inch of tread of rear of wheels until thoroughly consolidated. The binder shall then be spread over the crushed stone in small quantities and shall be swept and rolled into the voids, care being taken to form no surface crust. More binder shall be spread, swept, and rolled as many times as may be necessary to fill all voids and until the crushed stone ceases to sink or creep under the roller. No rolling shall be done when the binder is wet, and the binder shall not be dumped or stored on the crushed stone. If, during the construction, the subgrade is forced below its proper level or up into the voids of the crushed stone, the contractor shall, without cost to the Borough, remove and replace loose and unstable subgrade material, reshape the subgrade, and replace and reconsolidate the base course to the satisfaction of the Borough Engineer.
B.
The finished base course shall be at the prescribed
grade and contour, shall have the required depth and width, shall
be free from excess binder, ruts, and loose stones, and shall show
no evidence of instability or other defects.
