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Publication Number: FHWA-RD-07-052
Date: September 2007
This LTPP protocol covers the determination of the penetration of extracted asphalt cements at 77°F (25°C) and 115°F (46°C).
This test shall be carried out in accordance with AASHTO T49-89 with the exception of some of the sections of the reference standard which have been modified as presented below. In all other remaining sections, AASHTO T49-89 shall be followed as written. The test will be carried out on asphalt cement specimens extracted from AC core and block samples, as well as uncompacted samples of both virgin and recycled aggregate mixtures recovered from test sections included in the LTPP experiments. The asphalt cement shall be recovered from the AC cores and asphalt-aggregate mixtures by the Abson method specified in LTPP Protocol P21.
1.1 This method describes a procedure for determining the penetration of extracted asphalt cement at two temperatures (77°F [25°C] and 115°F [46°C]).
2.5 LTPP Protocol
Protocol P21 - Recovery of Asphalt from Solution by the Abson Method.
7.1 Heat the extracted asphalt cement sample with care to prevent local overheating until it has become fluid. Then with constant stirring, raise the temperature of the asphalt cement sample to not more than 180°F (100°C) above its estimated or expected softening point. Avoid the inclusion of air bubbles. To reach the pouring temperature, do not heat the softened sample more than 30 minutes. Then, pour it into the sample container to a depth, that when cooled to the temperature of test, is at least 10 mm (0.4 in.) greater than the depth to which the needle is expected to penetrate. Pour separate samples for each of the test temperatures (77°F [25°C] and 115°F [46°C]).
8.1 The conditions of the test (i.e., temperature, load, and time) for this protocol shall consist of (1) 77°F (25°C), 100 g (0.2 lb) and 5 s and (2) 115°F (46°C), 100 g (0.2 lb) and 5 s.
In accordance with Section 9 of AASHTO T49-87 for two separate specimens from the same asphalt cement sample at 77°F (25°C) and 115°F (46°C) (i.e., one at 77°F [25°C] and one at 115°F [46°C]).
9.4 Calculate the Penetration Index using the following formula:
where: PI = Penetration Index and
Pens in millimeters @ 100 gm., 5 sec.
Report the following information on Form T22.
10.1 Sample identification shall include: Laboratory Identification Code, Region, State, State Code, SHRP ID, Field Set Number, Sampling Area Number, Layer Number, Location Number and LTPP Sample Number.
10.2 Test Identification shall include: LTPP Test Designation, LTPP Protocol Number, Laboratory Test Number and the Test Date.
10.3 Test Results
10.3.1 Report, to the nearest whole unit, the average of at least three penetrations on the same sample, whose values do not differ by more than the amount shown below for each test temperature:
|Penetration||Max Difference Between Highest and Lowest PEN|
|P = 49||2|
|50 = P = 149||4|
|150 = P = 249||6|
|250 = P||8|
10.3.2 If the differences are exceeded, repeat the test using a second sample from the same batch of asphalt cement.
10.3.3 If the appropriate tolerance is again exceeded, ignore all results and repeat the test completely.
10.3.4 Penetration index to the nearest decimal place.
10.3.5 Comments shall include LTPP standard comment code(s) as shown in Section 4.3 of this Guide, and any other note as needed.
LTPP LABORATORY MATERIAL HANDLING AND TESTING
LABORATORY MATERIAL TEST DATA
PENETRATION OF EXTRACTED ASPHALT CEMENT AT 77 AND 115°F
TEST DATA SHEET T22
ASPHALT CONCRETE LAYER (ASPHALT CEMENT PROPERTIES)
LTPP TEST DESIGNATION: AE02/LTPP PROTOCOL P22
LABORATORY PERFORMING TEST:______________________________________________________________PRIVATE
LABORATORY IDENTIFICATION CODE: __ __ __ __
REGION _________________ STATE ___________________ STATE CODE __ __
EXPERIMENT NO _____ SHRP ID __ __ __ __
SAMPLED BY: ______________________________________________ FIELD SET NO. __ __
DATE SAMPLED: __ __-__ __-__ __ __ __ SAMPLING AREA NO. SA-____
1. LAYER NUMBER (FROM LAB SHEET L04 AND FORM T01B) __
2. LOCATION NUMBER __ __ __
3. LABORATORY TEST NUMBER __
4. LTPP SAMPLE NUMBER __ __ __ __
5. PENETRATION @ 77°F (millimeters) __ __ __.
6. PENETRATION @ 115°F (millimeters) __ __ __.
7. PENETRATION INDEX __.__
(a) CODE __ __ __ __ __ __ __ __ __ __ __ __
(b) NOTE _______________________________________________________
9. TEST DATE __ __-__ __-__ __ __ __
|SUBMITTED BY, DATE||CHECKED AND APPROVED, DATE|
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