The contractor shall prepare the subgrade to a width of 32 feet to receive
the pavement and concrete curbs in conformity with the lines and grades as
shown on the plans. Before the base material is placed upon the subgrade,
it shall be shaped to line and grade and compacted with an approved self-propelled
roller weighing not less than 10 tons. All hollows and depressions which develop
under rolling shall be filled with acceptable granular material and shall
again be rolled. Granular materials used to fill depressions shall consist
of approved hard, durable particles, 100% of which shall pass a one-half-inch
sieve and not more than 5% of which shall pass a No. 200 sieve. This process
of shaping and rolling and filling shall be repeated until no depressions
develop. The subgrade shall not be muddy nor otherwise unsatisfactory when
the base material is placed upon it. If soft spots develop during the rolling,
the material shall be removed and replaced with acceptable granular material
as above.