INSTRUCTIONS FOR RAM IN ASPHALT MIXTURES
This IM describes requirements for processing, storing, documenting, and sampling & testing of Recycled Asphalt Materials (RAM) intended for use in asphalt mixtures. RAM shall apply to Recycled Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS).
All notifications and documentation shall be submitted to the District Materials Engineer (DME) based on the District responsible for the location of the initial RAM stockpile.
A) RAP
RAP suitable for asphalt mixtures shall be processed by milling and/or crushing up to a maximum particle size of 1.5 inches. The Contractor shall notify the Engineer and DME 48 hours before processing begins.
Additional screening or blending may be done to achieve a more uniform stockpile. This processing may be done as the stockpile is built or as part of the asphalt plant production. Additional actions that may improve the consistency of the RAP include further crushing to reduce top size, screening into coarse and fine fractions, or blending by proportioning through a calibrated two-bin cold feed. Each individual RAP stockpile being incorporated into asphalt mixtures must have a dedicated totalizer for measuring quantities during production. When using multiple RAP stockpiles for a single mix, if the required number of totalizers are not available pre-blend the piles to the JMF proportions under the direction of the DME.
B) RAS
End users of RAS which also receive raw, unprocessed shingles and process the material for incorporation into an asphalt mixture, shall be considered a shingle Supplier and must adhere to Materials IM 506.
A) RAP
Place stockpiles on a base with adequate drainage, sufficient to prevent contamination, constructed in layers to minimize RAP segregation and ensure a workable face. Track equipment may operate on the stockpile during its construction.
To meet Classified RAP criteria, separate stockpiles shall be constructed for each source of RAP based on the quality of aggregate, type and quantity of asphalt binder, and size of processed material. Notify the Engineer and DME 48 hours prior to blending Classified RAP materials of the same aggregate quality to retain Classified status.
B) RAS
Place stockpiles on a base with adequate drainage sufficient to prevent contamination.
Separately stockpile pre-consumer RAS from post-consumer (tear-off) RAS. RAS may be pre-blended with RAP under the direction of the Engineer. Notify the Engineer and DME 48 hours prior to blending RAS materials with other materials or adding to a RAS stockpile. Equipment must be calibrated to ensure proper proportioning of blended piles. The Engineer may require verification testing for asphalt content, gradation, aggregate specific gravity, aggregate absorption, and fine aggregate angularity before the pile may be used.
A) RAP
Stockpiled RAP material will only retain its Classified status when the following documentation requirements are met. No documentation is required when the RAP is used on the project it came from, or a tied project.
§ Identification of the project from which the material was removed.
§ Mix data from the original project including mixture type.
§ Aggregate classification.
§ Location and depth in the pavement structure.
§ Extracted gradation information, if available.
§ Description of stockpile location and quantity.
§ Form 820009r (see Appendix A) is completed by the RAP owner and a copy is forwarded to the DME within 10 calendar days of completing the stockpile.
§ Any special handling, treatment or conditions of the RAP or its use should be described on this form.
§ Maps shall provide details that depict the stockpile site, including adjacent stockpiles of RAP or aggregates, permanent plant equipment, and landmarks.
Maps and signs shall identify the stockpile by RAP Identification Number.
The DME will review Form 820009r for accuracy. Portions of the form including assigning the RAP identification number, aggregate quality type, crushed particle and friction type credit, average values for extracted aggregate gradation, aggregate bulk specific gravity, aggregate absorption and asphalt binder content will be furnished by the DME.
Notify the DME at least 48 hours before relocating or reprocessing a Classified RAP stockpile for future use (not intended for a specific project). The notification shall include the estimated quantity of RAP being relocated or reprocessed and the new location of the stockpile. Relocation of RAP shall be reported on the appropriate Form (820009r) and submitted to the DME within 10 calendar days of completing the relocation. Reprocessing a Classified RAP stockpile may require additional sampling, testing, and a new Form (820009r) with reassignment of a RAP Identification Number.
Before January 1st of each year, the Contractor shall update Form 820009r on the status of each RAP stockpile. Report the estimated quantity of RAP removed for the construction season completed and the available RAP in each stockpile for future use.
B) RAS
The following documentation is required for owners of stockpiled RAS:
· Form 820009ras (see Appendix B) is completed by the stockpile owner and a copy is forwarded to the DME within 10 calendar days of completing the stockpile.
· Any special handling, treatment or conditions of the RAS should be described on this form.
· A record of addition and consumption of the RAS stockpile should be documented on this form.
· Maps shall provide details that depict the stockpile site, including adjacent stockpiles of RAP or aggregates, permanent plant equipment, and landmarks.
· Maps and signs shall identify the stockpile by RAS Identification Number.
The DME will review forms for accuracy. Portions of the form including assigning the stockpile identification number, average values for extracted aggregate gradation, and asphalt binder content will be completed by the DME.
Notify the DME at least 48 hours before relocating or reprocessing a RAS stockpile for future use (not intended for a specific project). The notification shall include the estimated quantity of RAS being relocated or reprocessed and the new location of the stockpile. Relocation of RAS shall be reported on the appropriate Form (820009ras) and submitted to the DME within 10 calendar days of completing the relocation. Reprocessing a RAS stockpile may require additional sampling, testing, and a new Form (820009ras) with reassignment of a RAS Identification Number.
Before January 1st of each year, the Contractor shall update Form 820009ras on the status of each RAS stockpile. Report the estimated quantity of RAS removed for the construction season completed and the available RAS in each stockpile for future use.
A) RAP
A certified Level I Aggregate Technician shall obtain the samples. Significant mixture differences in the pavement to be recycled may require separate stockpiles and samples. A sampling plan shall be developed by the Contractor and approved by the DME prior to sampling.
Samples for mix design obtained from the RAP stockpile are preferred, but not always available when the mix designs are performed. Samples shall be obtained from at least 3 locations. When stockpile samples are not available, RAP samples shall be obtained by milling a minimum of 50 feet of project length at each sample location. Other methods of sampling for mix design may only be used with the approval of the DME.
Obtain sufficient material for contractor mix design testing and owner agency RAP extraction testing as recommended in Materials I.M. 510. A representative 30 pound sample split from the total sample shall be delivered to the District Materials Laboratory for extraction testing. Results of the extraction test will be provided to the Contractor within 4 weeks of sample delivery.
B) RAS
When RAS is to be used on an existing contract, the DOT will perform mix design testing on samples from the certified stockpile dedicated to the project at the plant. Samples may also be collected at an in-state source. For out-of-state sources, the DME may approve mix design sampling and testing to be coordinated by the Contractor and Supplier at a qualified lab for preliminary information. Mix designs may then be given conditional approval pending DOT results. When the Contractor retains possession of the RAS, the DOT will sample and test. DOT results shall be available prior to start-up. Adjustments to the mix design may be required.
When mix design development needs to be expedited for an active DOT contract and the Supplier has not had sufficient time to certify the pile’s quality (gradation and deleterious content), extraction samples may be taken by the District directly at the Supplier’s site provided the material is certified free of asbestos containing materials (ACM). Provide a certification letter to the DME using guidelines in Materials IM 506 Appendix E. The Central lab will run extraction and material quality (gradation and deleterious content) testing on the sample. In the event of a failing quality test, the District may sample and test (gradation and deleterious) again after the Supplier has certified the material quality.
A certified Level I Aggregate Technician shall obtain the samples. RAS shall be sampled using methods similar to those for fine aggregate. Samples for mix design testing shall be obtained from at least 3 locations. A sampling plan shall be developed by the Contractor and approved by the DME prior to sampling.
Obtain sufficient material for contractor mix design testing and owner agency extraction testing as recommended in Materials I.M. 510. Samples shall be witnessed and secured. A representative 30 pound sample split from the total sample shall be delivered to the District Materials Laboratory for extraction testing. Results of the extraction test will be provided to the Contractor within 4 weeks of sample delivery.
Include extracted asphalt content and dry RAS gradation in testing.
In lieu of a sieve analysis on the extracted aggregate, the following gradation may be assumed for the RAS aggregate:
|
Shingle Aggregate Gradation |
|
|
Sieve Size |
Percent Passing by Weight |
|
3/8 in. |
100 |
|
No. 4 |
95 |
|
No. 8 |
85 |
|
No. 16 |
70 |
|
No. 30 |
50 |
|
No. 50 |
45 |
|
No. 100 |
35 |
|
No. 200 |
25 |
When the contractor elects to perform RAP quality control, use one of the following quality control sampling programs. A certified Level I Aggregate Technician shall obtain the samples.
· Stockpiles – The Contractor shall obtain a representative sample of RAP from the stockpile for each 1000 tons of RAP placed in the stockpile.
· Asphalt Plant – The Contractor shall obtain a representative sample of RAP from the RAP feed belt for each 7000 tons of mixture produced.
The Contractor shall use the ignition oven (Materials I.M. 338) or chemical extraction (AASHTO T 164) to extract the aggregate from the RAP sample. Calibration of the asphalt binder content from the ignition oven extraction is not required for the RAP quality control program. The gradation of the extracted RAP aggregate and the un-calibrated asphalt binder content shall be logged and charted within 24 hours of sampling. Report results to the DME upon completion of testing.
To retain Classified RAP status for undocumented sources, the stockpile shall be uniform in gradation and binder content. The contractor shall perform ignition oven (Materials IM 338) testing for aggregate gradation and binder content at 1/1000 tons as the stockpile is built or during processing of the stockpile. Regardless of tonnage, a minimum of three tests shall be required. Interior samples from the stockpile cross section shall be included in quality control testing. The contractor shall perform and report aggregate specific gravity and absorption testing at the above frequencies. Retain a split portion of each sample for testing by the Iowa DOT.
Gradation and asphalt content uniformity will be based on the standard deviation requirements listed in Table 1. If the Contractor results satisfy the requirements in Table 1, the District will select a sample to test a burn-off gradation for verification. If the tolerances in IM 216 are met, the Contractor’s results will be validated and the pile will be classified. Asphalt content need not be verified with IM 216 tolerances. Log, chart, and report all test results to the DME using the spreadsheet (http://www.iowadot.gov/Construction_Materials/hma/CertifiedRAPWorksheet.xlsx). The procedure outlined in Materials I.M. 501 will be used to identify an outlier on each sieve size and binder content.
Table 1: Variability requirements for Classified RAP from Undocumented Source
|
Property |
Maximum Standard Deviation |
|
1 ½ (% Passing) |
5.0 |
|
1 (% Passing) |
5.0 |
|
¾ (% Passing) |
5.0 |
|
⅜ (% Passing) |
5.0 |
|
#4 (% Passing) |
5.0 |
|
#8 (% Passing) |
5.0 |
|
#30 (% Passing) |
5.0 |
|
#200 (% Passing) |
1.5 |
|
Asphalt Content (%) |
0.50 |
The DME will provide notification of Classified status when the above requirements are satisfied.
Only when the owner of the stockpile of a RAP material is an asphalt contractor, the Iowa Department of Transportation or a local agency, should RAP samples be submitted to the Office of Construction & Materials for Vacuum Extraction of Bitumen and Mechanical Analysis of Extracted Aggregate. Ownership of the RAP should be verified so the test results are provided to the rightful owner.
These tests on samples representing stockpiles of any RAP not owned by one of the owners described in the preceding paragraph, shall not be submitted to Office of Construction & Materials for testing, unless directed by the DME. Until it is certain that these RAP materials will be used in Department projects, the owner may be advised to seek a qualified commercial testing lab to perform these tests.
CREDIT FOR FRICTION AND CRUSHED PARTICLES
The Engineer will use the following guidelines to determine credit for friction and crushed particles when blending multiple piles or milling multiple lifts:
Example:
Your firm is milling 3” of existing pavement using 1 pass of the mill. Of that 3”, 2” is from a surface mix, 1” was from a base mix.
From the paving records you determine the base mix had:
A. 20% crushed clean 3/4” type 4 limestone with 15% passing the number 4 sieve.
B. 20% crushed 3/4” type 4 limestone with 36% passing the number 4 sieve.
C. 10% crushed 1/2” type 4 limestone with 42% passing the number 4 sieve.
D. 25% crushed type 4 limestone manufactured sand with 97% passing the number 4 sieve.
E. 25% type 5 washed sand with 98% passing the number 4 sieve.
From the paving records you determine the surface mix had:
F. 17% crushed 3/4” type 3 gravel with 6% passing the number 4 sieve.
G. 16% crushed 3/8” type 4 limestone with 57% passing the number 4 sieve.
H. 11% crushed 1/2” type 4 limestone with 42% passing the number 4 sieve.
I. 32% crushed limestone manufactured sand with 95% passing the number 4 sieve.
J. 24% type 5 washed sand with 98% passing the number 4 sieve.
The base lift is 1”/ 3” or 33.33% of the rap.
The surface lift is 2”/ 3” or 66.67% of the rap.
Aggregate A from above was 20% of the original base mix aggregate. The base was 33 1/3% of the total rap milled. 85% was retained on the 4. 15% passed the 4. For this rap blend:
· Aggregate A contributed (20%)*(33 1/3%)*(85%) or 5.67% (see below) Type 4 plus 4 sieve material to the aggregate total.
· Aggregate A contributed (20%)*(33 1/3%)*(15%) or 1% (see below) Type 4 minus 4 sieve material to the aggregate total.
This can be done with every aggregate (as shown below).
|
|
Base |
Surface |
|
|
|
||||||||
|
A number |
Axxxxx |
Axxxxx |
Axxxxx |
Axxxxx |
Axxxxx |
Axxxxx |
Axxxxx |
Axxxxx |
Axxxxx |
Axxxxx |
|
|
|
|
Common name |
¾” C.L. |
¾” - L.S. |
½” - L.S. |
Man. Sand |
W. Sand |
¾” Cr. Gr |
3/8” - L.S. |
½” - L.S. |
Man Sand |
W. Sand |
|
|
|
|
Percent of original mix |
20 |
20 |
10 |
25 |
25 |
17 |
16 |
11 |
32 |
24 |
|
|
|
|
Volumetric % (Ratio of lift compared to total lift milled) |
33% |
33% |
33% |
33% |
33% |
67% |
67% |
67% |
67% |
67% |
0% |
0% |
|
|
% (percent of total mix) |
6.67 |
6.67 |
3.33 |
8.33 |
8.33 |
11.33 |
10.67 |
7.33 |
21.33 |
16.00 |
0 |
0 |
|
|
Retained (+4) |
85 |
64 |
58 |
3 |
2 |
94 |
43 |
58 |
5 |
2 |
100 |
100 |
|
|
Passing (-4) |
15 |
36 |
42 |
97 |
98 |
6 |
57 |
42 |
95 |
98 |
0 |
0 |
|
|
Aggregate percentage as a decimal |
0.066667 |
0.066667 |
0.033333 |
0.083333 |
0.083333 |
0.113333 |
0.106667 |
0.073333 |
0.213333 |
0.16 |
0 |
0 |
|
|
Aggregate Type |
4 |
4 |
4 |
4 |
5 |
3 |
4 |
4 |
4 |
5 |
0 |
0 |
|
|
Type 2 or better |
No |
No |
No |
No |
No |
No |
No |
No |
No |
No |
No |
No |
|
|
Type 3 or better |
No |
No |
No |
No |
No |
Yes |
No |
No |
No |
No |
No |
No |
|
|
Type 4 or better |
Yes |
Yes |
Yes |
Yes |
No |
Yes |
Yes |
Yes |
Yes |
No |
No |
No |
|
|
Crushed y-yes n-no |
Y |
Y |
Y |
Y |
N |
Y |
Y |
Y |
Y |
n |
|
|
|
|
Type___ or better |
Yes |
Yes |
Yes |
Yes |
No |
Yes |
Yes |
Yes |
Yes |
No |
No |
No |
Total |
|
Plus 4 type 4 credit = |
5.67 |
4.27 |
1.93 |
0.25 |
0.00 |
10.65 |
4.59 |
4.25 |
1.07 |
0.00 |
0.00 |
0.00 |
32.68 |
|
Plus 4 type 3 credit = |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
10.65 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
10.65 |
|
Plus 4 type 2 credit = |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
|
Minus 4 type 4 credit = |
1.00 |
2.40 |
1.40 |
8.08 |
0.00 |
0.68 |
6.08 |
3.08 |
20.27 |
0.00 |
0.00 |
0.00 |
42.99 |
|
Minus 4 type 3 credit = |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.68 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.68 |
|
Minus 4 type 2 credit = |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Plus 4 |
5.667 |
4.267 |
1.933 |
0.250 |
0.167 |
10.653 |
4.587 |
4.253 |
1.067 |
0.320 |
0.000 |
0.000 |
33.16 |
|
Minus 4 |
1.000 |
2.400 |
1.400 |
8.083 |
8.167 |
0.680 |
6.080 |
3.080 |
20.267 |
15.680 |
0.000 |
0.000 |
66.84 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
% plus 4 type 4 or Better=32.68/33.16= |
98.5% |
|
Type 5 aggregate |
13.00% |
|
|
|
|
|
|
|
|
|
|
% plus 4 type 3 or Better=10.65/33.16= |
32.1% |
|
Type 4 aggregate |
75.67% |
|
|
|
|
|
|
|
|
|
|
% plus 4 type 2 or Better=0/33.16= |
0.0% |
|
Type 3 aggregate |
11.33% |
|
|
|
|
|
|
|
|
|
|
% minus 4 type 2 or Better=0/66.84= |
0.0% |
|
Type 2 aggregate |
0.00% |
|
|
|
|
|
|
|
|
|
|
% minus 4 type 3 or Better=.68/66.84= |
1.0% |
|
|
|
|
|
|
|
|
|
|
|
|
|
% minus 4 type 4 or Better=42.99/66.84= |
64.3% |
|
|
|
|
|
|
|
|
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|
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|
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|
|
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|
Crushed credit in %= |
75.67 |
|
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|
% plus 4 type 4 =(32.68-10.65)/33.16= |
66.4% |
|
|
|
|
|
|
|
|
|
|
|
|
|
% plus 4 type 3 =10.65/33.16= |
32.1% |
|
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|
% plus 4 type 2 =0/33.16= |
0.0% |
|
|
|
|
|
|
|
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|
% minus 4 type 4 = (42.9-68)/66.84= |
63.3% |
|
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|
% minus 4 type 3 =.68/66.84= |
1.0% |
|
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|
|
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|
|
|
|
|
% minus 4 type 2 =42.99/66.84= |
0.0% |
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Note: Type three or two aggregate is shown as type four or better. When sorting by type this material cannot be counted more than once. |
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