1、Standard Practice for Sampling Asphalt Mixtures after Compaction (Obtaining Cores) AASHTO Designation: R 67-151American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2c R 67-1 AASHTO Standard Practice for Sampling Asphalt
2、 Mixtures after Compaction (Obtaining Cores) AASHTO Designation: R 67-1511. SCOPE 1.1. This method describes the process for removal of a core sample of compacted asphalt mixture from a pavement for laboratory testing. Cores may range in diameter from 2 in. to 12 in. 1.2. This standard does not purp
3、ort to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. SIGNIFICANCE 2.1. Samples obtained in acco
4、rdance with the procedure may be used for measuring asphalt mixture thickness, density, and other testing. 3. APPARATUS 3.1. Core Drilling MachineA power-driven wet-core drilling machine shall be used to obtain the sample. The device shall be capable of obtaining a core to the full depth of the asph
5、alt mixture sampled and shall consist of a rigid frame or platform such that the core barrel can be maintained perpendicular to the pavement during the drilling process. The core drilling machine must be of sufficient horsepower and have the ability to reach a sufficient depth to minimize distortion
6、 of the compacted cores of asphalt mixture. 3.2. Core Drill BitThe cutting edge of the core drill bit shall be made of hardened steel or other suitable material with diamond chips embedded in the metal or as recommended by the core drill bit manufacturer in order to drill through the compacted aspha
7、lt mixture cleanly. The inside diameter of the core barrel shall be as specified. 3.3. Separation EquipmentA saw or other method(s) that provides a clean, smooth plane representing the layer to be tested without damaging the specimen. 3.4. Retrieval DeviceA device for removing core samples that will
8、 preserve the integrity of the core. Note 1Suitable devices have been made from steel rods, wire, or banding material. 3.5. Cooling AgentSuch as water, ice, dry ice, or liquid nitrogen. 4. PROCEDURE 4.1. Freshly compacted asphalt mixtures shall be allowed sufficient time to cool prior to coring in o
9、rder to prevent damage to the core. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c R 67-2 AASHTO 4.1.1. To accelerate the coring process, compacted asphalt mixtures may be cooled to expedite the r
10、emoval of the core by the following methods: water, ice, dry ice, or liquid nitrogen. 4.2. Provide a means such as water or air to aid in the removal of cuttings and to minimize the generation of heat caused by friction. 4.3. Position the coring machine above the selected location. Engage power and
11、water or air source to coring machine. Slowly advance bit until contact with the compacted asphalt mixture surface. 4.4. Keep the core bit perpendicular to the compacted asphalt mixture surface, applying constant pressure during the process. Note 2If any portion of the coring machine shifts during t
12、he operation, the core may break or distort. Failure to apply constant pressure or applying too much pressure may cause the bit to bind or distort the core. 4.5. Continue the coring operation to the desired depth. 4.6. After drilling, use a retrieval device to obtain the core without damaging or dis
13、torting the sample. Note 3If the core is damaged to a point that it cannot be used for its intended purpose, a new core shall be obtained within 6 in. of the original location. 4.7. Clearly label the core with a sample marking tool. 4.8. Fill the hole made from the coring operation with asphalt mixt
14、ure, non-shrink grout, or other suitable material. Consolidate or compact the material in the hole in multiple lifts if necessary. Ensure that the final surface is level with the surrounding surface. 5. TRANSPORTING SAMPLES 5.1. Transport cores in a manner that prevents damage from jarring, rolling,
15、 or impact with any object. 5.2. Prevent cores from freezing or from excessive heat during transport. Note 4In extreme ambient temperature conditions, an insulated container should be used during transport. 5.3. If the core is damaged in transport to a point it cannot be utilized for its intended pu
16、rpose, the core will not be used. 6. LAYER SEPARATION 6.1. Using appropriate separation equipment, separate two or more pavement courses, lifts, or layers along the designated lift line. Note 5Lift lines are often more visible by rolling the core on a flat surface. 7. REPORT 7.1. The report shall in
17、clude the following: 7.1.1. Date the cores were obtained. 7.1.2. Paving date. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c R 67-3 AASHTO 7.1.3. Coring location. 7.1.4. The lift/layer being evalu
18、ated. 7.1.5. Material type. 7.1.6. Average thickness if required. APPENDIX (Nonmandatory Information) X1. THICKNESS DETERMINATION X1.1. Measure the thickness of the designated lift to the nearest 0.01 ft, 1/8in., or 3 mm. Calculate an average of three or more measurements taken around the lift. 1This full standard was first published in 2015. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
