Section 308 β Emulsified Asphalt-Treated Base Course
Description
308.01This work consists of constructing a course of emulsified asphalt -treated base on a prepared surface.
Material
308.02Conform to the following Subsections: Emulsified asphalt 702.02 Subbase or base course aggregate 703.05(b) Water for construction 725.01(c)
Construction Requirements
308.03General. Prepare the surface according to Section 204 or 303 as applicable. After a representative quantity of aggregate is produced and at least 14 days before incorporating the aggregate into the work, submit the following:
(a)Proposed target values for base aggregate within the gradation ranges shown in Table 703-1 for the req uired grading; and
(b)A representative 400 -pound aggregate sample. Stop placement and resubmit new target values if the calculated mean value for a tested sieve differs from the target value by more than the allowable deviation for that sieve.
308.04Mixing and Spreading. Use a stationary pugmill with weighing, volumetric, or other gauging equipment that can control the material entering the mixer. Interlock the controls for the aggregate feed with the emulsified asphalt and water controls to ensure uniform introduction of material into the mixer. Determine the optimum moisture content of the mixture according to AASHTO T 180, Method D. Add aggregate and water to the mixer before the emulsified asphalt. Add 1 percent emulsified asphalt by mass of aggregate. Adjust the total liquid content (emulsified asphalt and water) to within 1 percent of the optimum moisture content at the time of compaction. Mix until particles are uniformly coated. Haul and place the treated aggregate immediately after mixing. Do not stor e emulsified asphalt -treated aggregates in stockpiles. Spread the mixture on the prepared surface in a uniform lift. Shape the mixture to the required line, grade, and cross -section. Route hauling equipment uniformly over the full width of the surface to minimize non-uniform compaction.
308.05Compacting. Compact the mixture according to Subsection 301.05.
308.06Surface Tolerance. Finish the surface according to Subsection 301.06.
308.07Maintenance. Maintain the emulsified asphalt -treated aggregate base course according to Subsection 301.07.
308.08Acceptance. See Table 308-1 for sampling, testing, and acceptance requirements. Emulsified asphalt will be evaluated under Subsections 106.02 and 106.03. Aggregate gradation, ππππ ππ200Index (SEP), and fractured faces will be evaluated under Subsection 106.05.
(a)Aggregate gradation. The upper and lower specification limits are equal to the calculated mean of all test results plus or minus the allowable deviations shown in Tables 703-1 and 703-2, except as follows:
(1)If the calculated mean value for a tested sieve exceeds the maximum gradation range value shown in Table 703-1, then the upper specification is equal to the maximum gradation value in Table 703-1 plus or minus the allowable deviation in Table 703-2.
(2)If the calculated mean value for a tested sieve is less than the minimum gradation range value shown in Table 703-1, then the lower specification is equal to the minimum gradation value in Table 703-1 plus or minus the allowable deviation in Table 703-2.
(b)SEP. See Table 308-1, Note (2) . The lower specification limit is 1.000.
(c)Fractured faces. The lowe r specification limit is 50 percent. Other aggregate quality properties will be evaluated under Subsections 106.02 and 106.04. Construction of emulsified asphalt -treated base course will be evaluated under Subsections 106.02 and 106.04.
Measurement
308.09Measure the Section 308 pay items listed in the bid schedule according to Subsection 109.02 and the following as applicable: When measuring emulsified asphalt- treated aggregate base by the cubic yard, measure in place. When measuring emulsified asphalt -treated aggregate base by the square yard, measure the length horizontally along the centerline of the roadway. Measure the width horizontally to include the top of emulsified asphalt -treated aggregate base width and allowable widening.
Payment
308.10The accepted quantities will be paid at the contract price per unit of measurement for the Section 308 pay items listed in the bid schedule, except the emulsified asphalt -treated aggregate base course contra ct price will be adjusted according to Subsection 106.05. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05 . Table 308-1 Sampling, Testing, and Acceptance Requirements
Material or
Product
(Subsection) Type of
Acceptance
(Subsection) Characteristic Category Test Methods
Specifications Sampling
Frequency Point of
Sampling Split
Sample Reporting
Time Remarks
Source
Aggregate
quality (703.05 ) Measured & tested for conformance (106.04 & 105) LA abrasion (coarse) β AASHTO T 96 1 per rock type but not less than 5 per material source(1) Source of material Yes Before using in work Not required if using
Government-
furnished sources
Durability
index β AASHTO T 210 " " " " "
Soundness
using sodium sulfate β AASHTO T 104 " " " " "
Aggregate
base,
Grading
C, D, & E
(703.05 ) Process control (153.03 ) Gradation β AASHTO T 11 & T 27 2 per day per stockpile minimum Crusher belt No 24 hours Not required if using
Government-
furnished sources
Fractured
faces β AASHTO T 335 " " " " " Table 308- 1 (continued) Sampling, Testing, and Acceptance Requirements
Material or
Product
(Subsection) Type of
Acceptance
(Subsection) Characteristic Category Test Methods
Specifications Sampling
Frequency Point of
Sampling Split
Sample Reporting
Time Remarks
Production
Aggregate
base,
Grading C, D,
& E Measured & tested for conformance (106.04) Moisture - density (maximum density) β AASHTO T 180, Method D(3) 1 per type & source of material Stockpile or
Production
output Yes Before using in work β
Emulsified
asphalt -treated aggregate base,
Grading
C, D, & E
(703.05 ) Statistical (106.05) Gradation β
AASHTO
T 30 1 per 1000 tons In-place, after compaction Yes 4 hours β β in I No. 4 I
Other
specified sieves II
Fractured
faces I ASSHTO T 335 " " " " β
Sand
equivalent β AASHTO T 176,
Alternate
Method No. 2,
Reference
Method " Belt feed before adding emulsified asphalt " " β SEP I (2) " β No β β
Emulsified
asphalt -treated aggregate base,
Grading
C, D, & E Measured &
tested for conformance (106.04 ) Density β AASHTO T 310 or other approved procedures 1 per 500 tons but not less than 1 per lift In-place, after compaction No Before placing next lift β Table 308- 1 (continued) Sampling, Testing, and Acceptance Requirements
Material or
Product
(Subsection) Type of
Acceptance
(Subsection) Characteristic Category Test Methods
Specifications Sampling
Frequency Point of
Sampling Split
Sample Reporting
Time Remarks
Finished Product
Emulsified
asphalt -treated aggregate base Measured & tested for conformance (106.04) Surface tolerance & grade β Subsection
301.06As directed Completed base surface No Before placing next lift or as requested β
(1)Submit at least five reports, but at least one report per rock type for each source. Submit reports dated within 1 year of intended use and include rock type and sample location. Obtain samples representative of aggregates being provided.
(2)SEP is a measure of a materialβs ability to perform based on the quality and quantity of fines present. Quality is represented by the sand equivalent (SE) and quantity is represented by the percent passing the No. 200 sieve (ππ200). SEP is computed as follows: For SE β₯ 29, ππππππ =ππππ ππ200 + 25 and for SE < 29, ππππππ =ππππ + 4 ππππ + ππ200. Where: SE = Plastic fines in graded aggregates and soils by using the sand equivalent test. See AASHTO T 176, Alternate Method No.2, Reference Method. P200 = Material finer than the No. 200 sieve in mineral aggregates by washing. See AASHTO T 11.
(3)At least 5 points per proctor.