Rev. 9-11-95
SUBBASE FOR CEMENT
CONCRETE PAVEMENT
304-R-199
The Standard Specifications are revised as follows:
SECTION 304, AFTER LINE 22, INSERT AS FOLLOWS:
Subbase for cement concrete
pavement shall consist of 100 mm (4 in.) of an aggregate drainage
layer placed over an aggregate separation layer. The thickness of
the separation layer shall be 75 mm (3 in.) for all alignments in
rural areas and new alignments in urban areas. The thickness of
the separation layer shall be 150 mm (6 in.) for existing
alignments in urban areas. The drainage layer shall consist of
coarse aggregate size No. 8, in accordance with 904.02, except
that it shall be 100 % crushed stone or slag. The separation
layer shall consist of compacted aggregate base type O, size No.
53, in accordance with 904.02, except when air-cooled blast
furnace slag is used, the percent passing the 75 :m (No. 200)
sieve shall be 10 to 12 percent.
SECTION 304, AFTER LINE 75, INSERT AS FOLLOWS:
Compaction of coarse aggregate
size No. 8 for subbase for cement concrete pavement shall be as
follows:
(a) Two passes shall be made with an
approved vibratory roller before trimming.
(b) One pass shall be made with a
tandem roller after trimming.
SECTION 304, BEGIN LINE 81, INSERT AS FOLLOWS:
304.07 Method of Measurement.
Subbase and subbase for cement concrete pavement will be
measured by the cubic meter (cubic yard) based on the theoretical
volume to neat lines as shown on the plans. The
SECTION 304, BEGIN LINE 90, INSERT AS FOLLOWS:
304.08 Basis of Payment. The
accepted quantities of subbase and subbase for cement concrete
pavement will be paid for at the contract unit price per
cubic meter (cubic yard) complete in place.
SECTION 304, AFTER LINE 97, INSERT AS FOLLOWS:
Subbase for Cement Concrete
Pavement...................................................................
m3(CYS)