PORTLAND CEMENT CONCRETE PAVEMENTS. 31 
with a roller weighing not less than ten (10) tons. All existing slopes and 
surfaces of embankments shall be plowed or scarified where additional fill is 
to be made, in order that the old and new material may bond together. When 
sufficient material is not available within the fence lines to complete the em- 
bankments, suitable borrow pits from which the contractor must obtain the 
necessary material will be designated by the engineer. If there is more mate- 
rial taken from the cuts than is required to construct the embankments, as 
shown on the plans, the excess material shall be used in uniformly widening 
the embankments or shall be deposited where the engineer may direct. Where 
embankments are formed of stone, the material shall be carefully placed so 
that all large stones shall be well distributed and the interstices shall be com- 
pletely filled with smaller stone, earth, sand, or gravel, so as to form a solid 
embankment. 
During the work of grading, the sides of the road shall be kept lower than 
the center and the surface maintained in condition for adequate drainage. 
The grading of any portion of the road shall be complete before any surfacing 
material is placed on that portion, and where the plans do not call for any sub- 
stantial change in the grade of any existing section of the road, the surface 
shall be completely scarified to a depth of three (3) inches or more before the 
subgrade is prepared. 
All excavated material 1 will be classed as earth and rock. Only rock in 
place which requires blasting for its removal and boulders of one-half cubic 
yard or more in volume will be classed as rock excavation. 
Materials obtained from excavation and used in embankments will be paid 
for as excavation only, though the contractor is required to shape and trim 
the embankments properly. Materials obtained from excavation and used for 
surfacing will be paid for only once and at the price bid for surfacing material. 
Quantities of materials moved in grading will be measured in excavation 
and the volumes determined by the average end area method, and no payment 
will be made for materials excavated outside the slope lines shown on the 
plans unless the additional excavation is ordered by the engineer. 
The contract prices for excavation shall be compensation in full for all the 
work which is required to be done under the heading " grading," except that 
an additional allowance at the rate of one and one-half (1£) cents per cubic 
yard per one hundred (100) feet will be made for all materials of excavation 
necessarily hauled more than five hundred (500) feet. The centers of gravities 
of cuts and corresponding embankments will be used in determining the length 
of haul, and if the center of gravity of the cut is more than five hundred (500) 
feet from the center of gravity of the corresponding fill, overhaul will be 
allowed for the entire amount of material in the cut for the actual distance in 
excess of five hundred (500) feet. 
DRAINAGE STRUCTURES. 
[Insert technical specifications for necessary drainage structures.] 
SUBGRADE. 
The subgrade, or that portion of the road upon which the concrete surface 
is to be laid, shall consist of good sound earth brought to the proper elevation, 
1 In general, it is more satisfactory to classify the materials of excavation and to invite 
unit-price bids rather than lump-sum bids. However, if unit-price bids are invited, it is 
important that the various quantities be accurately determined in order that the best bid 
may be selected. If lump-sum bids are desired, omit the following paragraphs. 
