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SS- DS-01094
(New)




DEVELOPMENTAL SPECIFICATIONS
FOR
REDUCTION OF HMA QC/QA CRITERIA FOR LOCAL AGENCIES


Effective Date
May 15, 2007


THE STANDARD SPECIFICATIONS, SERIES 2001, ARE AMENDED BY THE FOLLOWING
MODIFICATIONS AND ADDITIONS. THESE ARE DEVELOPMENTAL SPECIFICATIONS AND THEY
SHALL PREVAIL OVER THOSE PUBLISHED IN THE STANDARD SPECIFICATIONS.

Section 2303 of the Standard Specifications shall apply with the following modifications:

Replace Article 2303.04, B, of the Standard Specifications:

B. Plant Production.
The Contractor shall perform the sampling and testing to provide the quality control of the mixture
during plant production. Certified Plant Inspection as described in Section 2521 will be required on all
HMA plant production. All personnel performing production quality control testing shall be certified by
the Department.

Easy and safe access shall be provided to the location in the plant where samples are to be taken.

A "significant mix change" is defined as a single occurrence of an aggregate interchange of greater
than 5%, a single occurrence of an asphalt content change greater than 0.2%, or any deletion or
introduction of a new material into the mix.

1. Sampling and Testing.
Asphalt binder shall be sampled and tested to verify the quality of the binder grade. Asphalt
binder samples shall be taken, at random times, as directed and witnessed by the Engineer in
accordance with Materials I.M. 204.

Aggregate gradation control shall be based on cold feed gradation.

Three Aaggregate samples shall be taken per lot, at random times, as directed and witnessed by
the Engineer in accordance with Materials I.M. 204 and secured in accordance with I.M. 511 to
determine that materials are being proportioned in accordance with the specifications.

The hot HMA mixture shall be sampled, at random locations, as directed and witnessed by the
Engineer, in accordance with Materials I.M. 322 and secured in accordance with Materials I.M.
511.

Each day's production of a mix design shall be considered a lot. When the anticipated quantity for
the day is 2000 tons (2000 Mg) or more, that day's production shall be divided into four sublots, DS-01094, Page 2 of 5
the first sublot of each day shall be the first 500 tons (500 Mg) produced. The remaining
anticipated quantity for the day shall be divided into three sublots of equal size.

When the anticipated mix design quantity for the day is less than 2000 tons (2000 Mg), the first
daily sublot shall be the first 500 tons (500 Mg) produced. Additional daily sublots of 750 tons
(750 Mg) each will be established for mix production exceeding the first 500 tons (500 Mg).

The maximum number of paired hot HMA mixture samples required for acceptance of a lot will
not exceed four.

Paired samples shall not be taken from the first 100 tons (100 Mg) of mix produced each day or
the first 100 tons (100 Mg) of mix following a significant mix change.

The Contractor shall test the quality control sample of each production paired sample as follows:

Two gyratory specimens shall be prepared and compacted in accordance with Materials I.M.
325G and the results averaged to determine sample results.

Density shall be determined for each specimen in accordance with Materials I.M. 321.

The Contractor's field quality control laboratory compaction shall be used for field density
control. The laboratory density for field control will be the bulk specific gravity of compacted
mixture (G
mb
) at N
design
. Bulk specific gravity at N
design
will be determined by compacting
specimens to N
max
and back calculating the bulk specific gravity at N
design
.

The Theoretical Maximum Specific Gravity of the uncompacted mixture shall be determined
in accordance with Materials I.M. 350 or other test methods recognized by AASHTO or
ASTM.

The laboratory air voids shall be determined in accordance with Materials I.M. 501.

When liquid anti-strip additives are used, the Contractor shall satisfy one of the following methods
to regulate the quantity of additive.

a. The Contractor shall present Certification that the equipment used to measure and blend
the liquid anti-strip additive meets the anti-strip suppliers recommended practice, that the
equipment is directly tied to the asphalt binder supply system, and that the equipment has
been calibrated to the equipment manufacturers guidelines.

b. The Contractor shall test the binder to measure the quantity of liquid anti-strip additive in
the binder every 5000 tons (5000 Mg) of HMA production. The suppliers test method shall be
approved by the Engineer prior to use of the test.

c. The Contractor shall run AASHTO T 283 during production. If the Contractor is unable to
certify or test for the presence and quality, the Contractor shall run AASHTO T 283 each
10,000 tons (10,000 Mg) of production to measure the effectiveness of the additive. The test
results shall satisfy 80% TSR when compared to the dry strength of specimens prepared with
asphalt binder containing the anti-strip additive.

2. Production Control.
After the JMF is established, the combined aggregate furnished for the project, the quantity of
asphalt binder and laboratory air voids should consistently conform to the JMF, as target values,
and shall be controlled within the production tolerances given in Table 2. Plant production must
be controlled such that the plant produced HMA mixture will meet mixture design criteria for Air
Voids and VMA at N
design
gyrations of the gyratory compactor within the test tolerances given in
the table. The slope of the gyratory compaction curve of plant produced material shall be
DS-01094, Page 3 of 5
monitored and variations in excess of ±0.40 of the mixture design gyratory compaction curve
slope may indicate potential problems with uniformity of the mixture.

The gyratory mix design gradation control points for the size mixture designated in the project
plans will not apply to plant production control.

Table 2 - Production Tolerances
MEASURED CHARACTERISTIC
TARGET
VALUE (%)
SPECIFICATION
TOLERANCE (%)
(1)
Cold feed gradation No. 4 (4.75 mm)
and larger sieves
by JMF
± 7.0
Cold feed gradation No. 8 (2.36 mm)
by JMF
± 5.0
Cold feed gradation No. 30 (600 µm)
by JMF
± 4.0
Cold feed gradation No. 200 (75 µm)
by JMF
± 2.0
(2)
Daily asphalt binder content
by JMF
± 0.3
Field laboratory air voids
4.0
(3)
-0.5/+1.0
(4)
VMA
(5)
by JMF
± 1.0
(6)
(1)
- Based on single test unless otherwise noted.

(2)
- The filler/bitumen ratio of the plant produced mixture will be maintained
between 0.6 and 1.4.
(3)
- Unless otherwise specified.
(4)
- Based on the moving average of four test values.
(5)
- Restricted to an asphalt film thickness as specified for the level of HMA
mixture.
(6)
- Based on the daily lot average.

The Contractor shall strive for the target value of the percent air void and asphalt binder by
adjusting gradation and asphalt binder content.

The Contractor shall produce a mixture of uniform composition conforming to the JMF. If, during
production, the Contractor determines from quality control testing that adjustments are necessary
to the JMF to achieve the specified properties, adjustments to the JMF target gradation and
asphalt binder content values may be made.

Adjustments to the JMF aggregate proportions and asphalt binder content shall be made as a
result of the interactive process between the Contractor and the Engineer. The Contractor's
adjustment recommendations shall prevail, provided all specifications and established mix design
criteria are being met for plant production.

The voids in the mineral aggregate (VMA) and estimated film thickness shall be measured for
specification compliance every day of HMA production.

Quality control charts in accordance with Materials I.M. 511 shall be available and kept current
showing both individual test results and moving average values. Moving averages shall be based
on four consecutive test results. Moving averages may only restart in the event of a mandatory
plant shutdown for failure to maintain the average within the production tolerance. Control charts
shall include a target value and specification tolerances.

Laboratory voids for individual tests shall be calculated according to Materials I.M. 501, using the
individual density and individual maximum specific gravity determined for each sample. The
moving average of laboratory voids shall be the average of the last four individual laboratory
voids. DS-01094, Page 4 of 5

The Contractor shall monitor the test results and to make mix adjustments, when appropriate, to
keep the mixture near the target values. The Contractor shall notify the Engineer whenever the
process approaches a specification tolerance limit. One moving average point for laboratory air
voids outside the specification tolerance limit shall be cause to cease operations. The Contractor
shall assume the responsibility to cease operations, including not incorporating produced material
which has not been placed. The process shall not be started again until the Contractor notifies the
Engineer of the corrective action proposed.

Replace Article 2303.04, D, of the Standard Specifications:

D. Sampling and Testing.