U.S. Department of Transportation
Federal Highway Administration
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Washington, DC 20590
Federal Highway Administration Research and Technology
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Publication Number: FHWA-RD-07-052
Date: September 2007
This LTPP protocol covers the determination of the static modulus of elasticity and Poisson's ratio of PCC cores under longitudinal compressive stress. The test shall be carried out in accordance with ASTM C469-02 as modified by the following. Only sections of the referenced standard which have been modified are included below. In all other sections the standard (ASTM C469-02) shall be followed as written. The test shall be performed on cores obtained from LTPP projects. The specimens to be tested are as shown on the materials testing plans developed for each project.
For PCC pavement cores consisting of multiple layers, the test shall be conducted separately on the test specimens consisting of each of the concrete overlay layers and the original concrete pavement layer from each specified location after assigning proper layer numbers. Layer numbers shall be assigned using the field layer number information from Field Operations Information Form 2 of the field data packet or lab sheet L04. The following definitions will be used throughout this protocol.
(a) Core: An intact cylindrical specimen of the pavement material that is removed from the pavement by drilling at the designated location. A core can consist of, or include, one, two or more different layers.
(b) Layer: That part of the pavement produced with similar material and placed with similar equipment and techniques. The material within a particular layer is assumed to be homogeneous. The layer thickness can be equal to or less than the core thickness or length.
(c) Test Specimen: That part of the layer which is used for the specified test. The thickness of test specimens cored from the pavement can be equal to or less than the layer thickness.
1.1 This test covers the determination of chord modulus of elasticity (Young's) and Poisson's ratio for PCC cores when the test specimen has been placed under longitudinal compressive stress. Chord modulus of elasticity and Poisson's ratio are defined in ASTM E-6.
2.1 ASTM Standards: As listed in ASTM C469-02.
2.2 AASHTO Standards:
AASHTO T22-88I Compressive Strength of Cylindrical Concrete Specimens
AASHTO T24-86 Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
AASHTO T67 Load Verification of Testing Machines
AASHTO T231-87I Capping Cylindrical Concrete Specimens
2.3 LTPP Protocols
P61 Test Method for Determination of Compressive Strength of In-Place Concrete
P66 Test Method for Visual Examination and Thickness of Portland Cement Concrete Cores
3.1 This test method provides a stress to strain ratio value and a ratio of lateral to longitudinal strain for hardened concrete.
3.2 The modulus of elasticity and Poisson's ratio values, applicable within the customary working stress range of 0 to 40 percent of ultimate concrete strength, may be used in computing stresses for observed strains.
4.1 Add: The requirements of Section 5.1 of AASHTO T22-88I shall also be applied.
4.2 Compressometer - As described in ASTM C469-02
5.2 Drilled Core Specimens - The test specimen shall be prepared to achieve the desired length to diameter (L/D) ratio of 1.5 or greater by sawing or grinding the bottom (not to exceed 1 inch [25 mm]) and top (up to ½ inch [13 mm]) of the core of a PCC layer. If L/D ratio is less than 1.5 because of being a thin PCC layer, then this condition shall be recorded in the report.
PCC cores (obtained from the pavement) shall be stored flat side down, fully supported and at between 40 ° F (5 ° C) and 100 ° F (38 ° C) in an environmentally protected storeroom.
Prior to performing the test, the cores or cylinders shall be submerged in lime-saturated water at 73.4 ± 3 ° F (23 ± 1.7 ° C) for at least 40 hours immediately prior to performing the test.
5.3 Add: Capping of both ends of the test specimen can be accomplished by using the procedures of AASHTO T231-87I.
5.4 The length (L) of the test specimen can also be determined to the nearest 0.1 inch (3 mm) by averaging four measurements equally spaced around the specimen. The diameter (D) of the test specimen shall be measured to the nearest 0.01 inch (0.3 mm) by averaging two diameters measured by a caliper at right angles to each other near the mid-height of the specimen. The average diameter (D) shall be used to calculate the cross sectional area of the test specimen.
5.5 The test specimen shall be weighed immediately prior to the test and the weight recorded to the nearest 0.1 lb (0.05 kg). The unit weight shall be determined using LTPP Protocol P65.
6.2 Determine the compressive strength of the companion cores (as described in LTPP protocol P61) prior to the test for static modulus of elasticity).
6.5 The ultimate load is determined from the compressive strength tests performed on companion specimens.
6.8 After the test, the specimen shall be properly marked and placed into storage.
7.3 Calculate the modulus of elasticity (Ec) and Poisson's ratio (µ) by following Sections 7.1 and 7.2 of the standard (ASTM C469-02).
Select the value of S1 stress level that corresponds to a longitudinal strain specified in Section 7.1 of ASTM C469-02.
Select the value of S2 stress level corresponding to 40 percent of ultimate load (maximum load at failure) determined during the compressive strength test conducted earlier on the companion test specimen taken from the same or near the same sampling area.
The following information is to be recorded on Form T64.
8.1 Sample Identification shall include: Laboratory Identification Code, LTPP Region, State, State Code, SHRP ID, Layer Number, Field Set Number, Sample Area Number, Sample Location Number, LTPP Sample Number.
8.2 Test identification shall include: LTPP Test Designation, LTPP Protocol Number, Laboratory Test Number, Test Date.
8.3 Test Results
Report the following:
8.4 Comments shall include LTPP standard comment code(s) as shown in Section 4.3 of this Guide and any other note, as needed. Additional codes for special comments associated with testing are given below.
|41||Length to diameter ratio was less than 1.5 because the layer was equal to or less than the diameter of the specimen.|
|42||Length to diameter ratio was equal to or less than 1.5 because the specimen was sawed in order to remove concrete with embedded steel.|
|43||Embedded steel was noted in the specimen near the middle of the diametral plane.|
|44||Embedded steel was noted at or near the side of the test specimen.|
|45||The specimen was trimmed only at the bottom end.|
|46||The specimen was trimmed only at the top end.|
|47||The specimen was trimmed at the top and bottom ends.|
8.5 Use Form T64 (Test Sheet T64) to report the above information (Items 8.1 to 8.4).
LTPP LABORATORY MATERIAL HANDLING AND TESTING
LABORATORY MATERIAL TEST DATA
STATIC MODULUS OF ELASTICITY OF PCC CORES
LAB DATA SHEET T64
PORTLAND CEMENT CONCRETE
TEST DESIGNATION PC04/PROTOCOL P64
LABORATORY PERFORMING TEST:______________________________________________________________
LABORATORY IDENTIFICATION CODE: __ __ __ __
REGION _________________ STATE ___________________ STATE CODE __ __
EXPERIMENT NO _____ SHRP ID __ __ __ __
SAMPLED BY: ______________________________________________ FIELD SET NO . __
DATE SAMPLED: __ __-__ __-__ __ __ __
1. LAYER NUMBER (FROM FIELD OPERATIONS FORM 2 AND/OR LAB SHEET L04) __
|2. SAMPLING AREA NO. (SA-)||__ __||__ __|
|3. LABORATORY TEST NUMBER||__||__|
|4. LOCATION NUMBER||__ __ __||__ __ __|
|5. LTPP SAMPLE NUMBER||__ __ __ __||__ __ __ __|
|6. DIAMETER (D), INCHES||__.__ __||__.__ __|
|7. SPECIMENT LENGTH (L), INCHES||__ __.__||__ __.__|
|8. L/D RATIO||__.__ __||__.__ __|
|9. UNIT WEIGHT (CW), PCF||__ __ __.||__ __ __.|
|10. MODULUS OF ELASTICITY (Ec), PSI||__ __ __ __ __ __ __.||__ __ __ __ __ __ __.|
|11. POISSON'S RATIO (µ)||0.__ __||0.__ __|
|(a) CODE||__ __ __ __ __ __||__ __ __ __ __ __|
|__ __ __ __ __ __||__ __ __ __ __ __|
|13. TEST DATE||__ __-__ __-__ __ __ __||__ __-__ __-__ __ __ __|
|NOTE: STRESS STRAIN PLOTS MADE AND ATTACHED (CHECK YES OR NO)||YES NO||YES NO|
|SUBMITTED BY, DATE||CHECKED AND APPROVED, DATE|
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