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Section 23 – Asphalt Concrete

When placing the initial mat of asphalt concrete on existing pavement, the end of the screed

nearest the centerline shall be controlled by a sensor activated by a ski device not less than

twenty-eight feet (28’) long. When paving contiguously with previously placed mats, the end of

the screed adjacent to the previously placed mat shall be controlled by a sensor that responds

to the grade of the previously placed mat and will reproduce the grade in the new mat within a

0.01-foot tolerance. The end of the screed farthest from the previously placed mat shall be

controlled in the same manner as when placing the initial mat.

Should the automatic screed controls fail to operate properly during any day’s work, the

Contractor may use manual control of spreading equipment for the remainder of that day.

However, the equipment shall be corrected or replaced with alternative automatically controlled

equipment conforming to the requirements in this Section before starting another day’s work.

Lines for the paver to follow in placing individual lanes shall be parallel to the centerline of

the roadway or to a baseline established by the Agency. Longitudinal pavement joints shall be

on, or as close as possible to, the lane lines shown on the Plans. The Agency shall determine

the locations of the longitudinal pavement joints.

Transverse construction joints and temporary runoff tapers shall be constructed so that no

gradual ramping down of the mat occurs back from the joint. Bond breaking paper may be

required under the runoff taper for later removal if specified by the Special Provisions.

The Contractor shall furnish equipment capable of producing the required compaction. For

vibratory rollers, the vibratory mode shall automatically shut off when machine direction is

23-8.05.A Density requirements - Minor Streets

All asphalt concrete paving placed on minor streets shall be constructed so as to produce

material with a density of not less than 94%, nor greater than 99%, as determined by nuclear

gage testing. For all such paving, the Contractor shall provide quality control testing at

directed by the County inspector, but not less than one test per five hundred (500)

tons. The average density shall fall in a range of 95% - 97%. The Contractor shall notify the

County inspector prior to paving and provide contact information for outside lab personnel. The

Agency reserves the right to conduct parallel quality assurance testing at its discretion in

accordance with Caltrans test methods 304, 308, and 375. Asphalt concrete paving placed on

residential and collector streets as defined above are exempt from the pay reduction factors

included in Section 23-9.02, “Pay Factors”, in these Standard Construction Specifications. If the

contractor elects to place the asphalt in two lifts, the base course of paving, the layer of asphalt

concrete that is constructed upon aggregate base (or upon subgrade for deep lift applications)

and that is to be followed by additional courses of asphalt concrete paving, shall be constructed

conforming to the requirements of Section 39-6.03, “Compacting”, of the State Standard

Specifications. For the base course of paving, the pay reduction factor included in Section 23-

9.02, “Pay Factors”, in these

Specifications shall not apply. Pavement sections consisting of a

single lift of asphalt concrete placed three inches (3”) thick shall not be considered to be base

23-8.05.B Density Requirements - Major Streets

On major streets, the base course of paving, the layer of asphalt concrete that is

constructed upon aggregate base (or upon subgrade for deep lift applications) and followed by

additional courses of asphalt concrete paving, shall be constructed conforming to the

requirements of Section 39-6.03, “Compacting”, of the State Specifications. For the base

course of paving, the pay reduction faction included in Section 23-9.02, “Pay Factors”, in these

Specifications shall not apply. Unless otherwise indicated in the Special Provisions, all