ITEM 309 – BITUMINOUS PLANT-MIX (STOCKPILE MAINTENANCEMIXTURE)
This Item shall consist of a bituminous stockpile maintenance mixture composed of aggregate, mineral filler, hydrated lime and bituminous material mixed in a central plant. The mixture is stockpiled for immediate or future maintenance needs.
309.2 Material Requirements
309.2.1 Composition and Quality of Bituminous Mixture
Same as Subsection 307.2.1
309.2.2 Bituminous Material
The type and grade of bituminous material shall be in accordance with the following guidelines:
MC 250 - For use within short time after stockpiling.
MC 800 - For immediate use under hot or moderate weather conditions, or for use within a short time after stockpiling.
CMS-2/2S - Mix can be designed for use within a short time after stockpiling or for long storage period.
*CMS - Cationic emulsified Asphalt.
309.2.3 Aggregate
It shall be crushed stone, crushed or natural gravel, slag, sand, stone or slag screenings, mineral dust, or a combination of these materials. The several aggregate fractions shall be combined in such proportions that the gradation of the composite aggregate shall conform to the grading requirements of Table 309.1.
The combined aggregate after going through the drier, shall have a sand equivalent value of not less than 40.
The coarse aggregate shall have a mass percent of wear not exceeding 40when tested by AASHTO T 96.Slag, if used, shall weigh not less than 1120 kg/m 3
Table 309.1 – Grading Requirements
Sieve Designation
|
Mass Percent Passing
|
|
Standard, mm
|
Alternate U.S. Standard
|
|
19.0
|
¾ in
|
100
|
12.5
|
½ in
|
80 – 100
|
9.5
|
3/8 in
|
70 – 90
|
4.75
|
No. 4
|
50 – 70
|
2.36
|
No. 8
|
35 – 50
|
0.60
|
No. 30
|
18 – 30
|
0.30
|
No. 50
|
15 – 25
|
0.15
|
No. 100
|
8 – 15
|
0.075
|
No. 200
|
4 - 10
|
309.2.4 Mineral Filler
It shall conform to the requirements of Item 307, Bituminous Plant Mix
Surface Course – General.
309.2.5 Hydrated Lime
It shall conform to the requirements of Item 307, Bituminous Plant Mix
Surface Course – General.
309.2.6 Proportioning of Mixture
The amount of bituminous material to be added will be from 4 to 10 mass
percent of total mix. The exact percentage to be used shall be fixed by the
Engineer in accordance with the job-mix formula and other quality control
requirements. Upper limit may be raised when using absorptive aggregate.
During the mixing operation, one-half to one (0.5 to 1.0) mass percent of
hydrated lime, dry aggregate basis, shall be added to the mixture. The
lower percentage limit is applicable to aggregates which are predominantly
calcareous.
309.3 Construction Requirements
309.3.1 Preparation of Mixture
The aggregate, mineral filler, and hydrated lime shall be fed into the
plant in the proportions required to provide a composite aggregate meeting
the grading requirements. The aggregate shall be free from visible moisture
at the time of mixing. The bituminous material shall be applied at the rate
and temperature specified by the Engineer. Mixing shall be thorough and
shall continue until all aggregate particles are well coated.
309.3.2 Stockpiling
The finished mixture shall be stockpiled on a platform level storage space.
309.4 Method of Measurement
The quantity of the bituminous mixture to be paid for will be the volume in
cubic meters as ordered and delivered in stockpiles.
309.5 Basis of Payment
The accepted quantity, measured as prescribed in Section 309.4, will be
paid for at the contract unit price for Bituminous Plant-Mix (Stockpile
Maintenance Mixture) which price and payment shall be full compensation for
furnishing and stockpiling the material including incidentals necessary to
complete the work prescribed in this Item.
Payment will be made under:
Pay Item Number
|
Description
|
Unit of Measurement
|
309
|
Bituminous Plant-Mix (Stockpile Maintenance Mixture)
|
Cubic Meter
|
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