STATE OF OHIO
DEPARTMENT OF TRANSPORTATION
SUPPLEMENTAL SPECIFICATION 874
ULTRATHINBONDED ASPHALT CONCRETE
April 18, 2008
874.01
874.02
874.03
874.04
874.05
874.06
874.07
874.08
874.09
874.10
Description
Materials
Composition
Equipment
Weather Limitations
Construction
Quality Control
Acceptance
Method of Measurement
Basis of Payment
874.01 Description. This work consists of constructing an ultrathin bonded asphalt concrete
wearing surface. The ultrathin bonded asphalt concrete consists of application of a warm polymer
modified asphalt emulsion followed immediately with a 5/8 inch (16mm) minimum hot asphalt
concrete overlay.
874.02 Materials. Conform to the following requirements:
A. Polymer Modified Emulsion. Conform to 702.16, Type B.
B.
PG Binder. Use a PG 70-22M asphalt binder.
C. Coarse Aggregate. Use approved coarse aggregates. Limit any coarse aggregate with
a water absorption value per Supplement 1031 of greater than 2.0 % to no more than 40% of
total coarse aggregate. Ensure coarse aggregates meet 703.05 and the following:
Tests
AASHTO T 104-94
ASTM D 4791
ASTM D 5821
AASHTO TP58-99
Description
Loss, sodium sulfate soundness test, % max
Flat & Elongated Ratio at 3:1, %
% Crushed, one / two faces
Micro-Deval, % loss
Specification
10 max
25 max
95 / 85 min
18 max
D. Fine Aggregate. Use approved fine aggregate. Ensure fine aggregate meets 703.05,
except for gradation, and the following:
Tests
Description
Specification
AASHTO T 176-86 Sand Equivalent
AASHTO TP 57-99 Methylene Blue, materials passing No. 200 (75 µm)
AASHTO T 304-96 Uncompacted Void Content
E.
45 min
10 max
40 min
Mineral Filler. Conform to 703.07.
874.03 Composition. Do not use reclaimed materials. Conform to 441.02 except as follows:
replace Table 441.02-1 with:
Sieve
1/2 inch (12.5 mm)
3/8 inch (9.5 mm)
No. 4
(4.75 mm)
No. 8
(2.36 mm)
No. 16
(1.18 mm)
No. 30
(600 um)
No. 50
(300 um)
No. 100 (150 um)
No. 200 (75 um)
Binder Content, %
(a)
Total Percent
Passing
100
85 - 100
28 – 38
25 – 32
15 – 24
10 – 18
8 – 14
6 – 10
4-6
4.8 - 5.6 (a)
Increase the upper limit on asphalt content by 0.5% when any coarse aggregate water
absorption value according to Supplement 1031 is greater than 2.0 %.
Select the JMF optimum PG binder content to meet the following criteria:
Perform tests A, B, and C of 441.04 and, if necessary, modify the mix per 441.04. Use 50 blow
Marshall compaction. Ensure the TSR is 0.80 minimum.
Perform draindown testing per AASHTO T 305. Use a test temperature of mixing temperature
plus 27 °F (15 °C) but do not exceed 350 °F (180 °C). Ensure the draindown is 0.10% maximum.
Calculate film thickness using effective PG binder content as follows. Film thickness will be 0.00035
inch (9 micron) minimum. If any coarse aggregate water absorption value per Supplement 1031 is
greater than 2.0 % film thickness will be 0.00039 inch (10 micron) minimum. If draindown is
exceeded 0.00035 inch (9 micron) will be allowed. Show data to validate draindown is
exceeded.
TF = V asp / SA x W
Where,
TF = Average film thickness, (in)
Vasp = Effective volume of asphalt cement (in3)
SA = Surface area of the aggregate (ft2 per lb. of aggregate)
W = Weight of aggregate (lb.)
Sieve size
1/2 inch (12.5 mm)*
3/8 inch (9.5 mm)*
No. 4 (4.75 mm)
No. 8 (2.36 mm)
No. 16 (1.18 mm)
No. 30 (600 :m)
No. 50 (300 :m)
No. 100 (150 :m)
No. 200 (75 :m)
Surface area
factor (constant)
(ft2/lb)
2
2
2
4
8
14
30
60
160
Example percent
Example
passing
surface area
(ft2/lb) **
100
92
1.84
36
0.72
26
1.04
17
1.36
13
1.82
10
3.00
8
4.80
4.5
7.20
Total surface area = 21.78 ft2/lb
* The surface area factor is 2 for any material above the No. 4 (4.75 mm) sieve
** Only calculate values if material is retained on the sieve
Film thickness calculation example:
Measured bulk specific gravity of the aggregates, G sb = 2.574
Effective specific gravity from the theoretical maximum density, G se = 2.627
Asphalt binder specific gravity, Gb = 1.025
Mixture asphalt content = 5.3%
Bulk density of the mixture, G mb = 2.161,
In accordance with AASHTO T 269 using 50 blow Marshall compaction.
Total volume of asphalt cement = total weight x asphalt content / (asphalt specific gravity x water
density)
= 1 lb. of mix x 5.3% / 1.025 x 8.34 lb./gallon
= 0.0062 gallon = 1.43 in3 total asphalt cement
Asphalt absorbed by weight of aggregate = 100 x (( G se - G sb) / Gsb Gse) x Gb
= 100 x ((2.627 – 2.574) / (2.574)(2.627)) x 1.025 = 0.803%
Weight of absorbed asphalt = percent of asphalt absorbed by weight of aggregate x weight of
aggregate
= 0.803% x 1 lb. of mix x 94.7% aggregate = 0.0076 lb. of absorbed asphalt
Volume of absorbed asphalt = weight of absorbed asphalt / asphalt specific gravity x water specific
gravity
= 0.0076 lb. / 1.025 x 8.34 lb./gallon = 0.000889 gallon
= 0.205 in3 absorbed asphalt
Effective volume of asphalt,
Vasp = total asphalt volume - volume of absorbed asphalt = 1.43 in3 – 0.205
in3 = 1.225 in3
Film thickness, TF = V a s p / SA x W
TF = (1.225 in3 / 21.94 ft2/lb x 1 lb. x 94.7%)
= 1.225 in3 / (20.78 ft2)(144 in2/ft2) = 0.00041 in
874.04 Equipment. Provide self-priming spreading equipment capable of spraying the polymer
modified asphalt emulsion with a metered mechanical pressure spray bar and applying the hot
asphalt concrete overlay in one pass at the rate of 30 to 90 ft/minute (10 to 30 m/minute). Place the
asphalt concrete on the polymer emulsion with no vehicle contact on the emulsion prior to asphalt
concrete placement. The selfpriming spreading equipment must incorporate a receiving hopper, feed
conveyor, storage tank for polymer modified asphalt emulsion, polymer modified asphalt emulsion
spray bar and a variable width, heated, vibratory tamper bar screed. Provide a screed with the ability
to be positively crowned at the center and have vertically adjustable extensions to accommodate the
desired pavement profile.
Use a minimum of two steel wheel rollers with a minimum capacity of 11 tons (10 metric
tons) and conforming to 401.13 for compaction.
Approval of the spreading equipment by the Engineer will be based on the demonstrated
capability of the equipment to uniformly apply the polymer modified asphalt emulsion, place the
asphalt mixture to the required cross-section, profile and alignment in an acceptable, finished
condition ready for rolling. All other equipment and tools will be approved by the Engineer. Maintain all
equipment and tools in satisfactory working condition at all times.
874.05 Weather Limitations. Place material only when the pavement surface temperature and the
ambient air temperature are not less than 50 °F (10 °C) at the time of placement. A damp pavement
surface is acceptable for placement if it is free of standing water and no rain is predicted to follow
prior to placement of the asphalt mixture.
874.06 Construction
A. Surface Preparation. Perform the following items prior to the commencement of paving
operations.
1. Protect and cover manhole covers, drains, grates catch basins and other such utility
structures with plastic or building felt prior to paving and clearly reference these for
location and adjustment after paving.
2. Remove thermoplastic traffic markings if greater than 1/4 inch (6 mm) thickness (ride
quality).
3. Fill surface irregularities greater than 1/2 inch (12 mm) deep with a material approved by
the Engineer. Ensure areas to be repaired are dry.
4. Thoroughly clean the entire pavement surface to be overlaid, giving specific attention to
accumulated mud and debris. Use pressurized water and/or vacuum systems to provide a
suitable surface for bonding.
B. Polymer Modified Emulsion Application. Spray the polymer modified asphalt
emulsion at a temperature 120 – 180 °F (50 – 80 °C). The sprayer will provide a uniform
application across the entire width to be overlaid. Apply emulsion at 0.17 gal/yd2 ± 0.07 gal/yd2
(0.8 l/m2 ± 0.3 l/m2). Make adjustments to the spray rate based upon the existing pavement
surface conditions and recommendations of the polymer modified asphalt emulsion supplier.
C. Asphalt Concrete Application. Apply the asphalt concrete at a temperature of 300 –
330 °F (150 – 165 °C) and spread over the polymer modified asphalt emulsion immediately after
its application. Use an application rate necessary to minimize fracturing of the top size aggregate
by the screed. The Engineer will determine the acceptable extent of fracturing at the edge of the
paving for tapering purposes.
D. Compaction. Compact the asphalt concrete using two rollers meeting the
requirements of Table 401.13-2 in the static mode. A three-wheel roller is not required. Do not
apply the roller capacity requirements of Table 401.12-1. Make a minimum of three roller
passes each. Complete roller passes before the material temperature has fallen below 185 °F (85
°C). Do not allow the rollers to remain stationary on the freshly placed asphalt concrete. Do not
open the asphalt concrete to traffic until the rolling operation is complete and the material has
cooled sufficiently to resist damage.
E. Hauling. Conform to 401.11.
874.07 Quality Control. The requirements of 441.09 will apply except as noted below.
Section B. Gradation: Do not apply requirements for the F-T value and F/A ratio.
Section C. Air Voids and MSG: Do not apply requirements for air voids and MSG.
874.08 Acceptance. Accept Ultrathin Bonded Asphalt Concrete according to 448. Do not
apply the requirements of Supplement 1055.
874.09 Method of Measurement. Measure the ultrathin bonded asphalt concrete according to
401.21
874.10 Basis of Payment. The Department will pay for accepted quantities, completed in place,
at the contract prices, or at the contract price as modified in 448.05, as follows:
Item
874
Unit
Cubic Yards ( Cubic Meters )
Description
Ultrathin Bonded Asphalt Concrete