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 x 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. 



