Tex-242-F, Hamburg Wheel-tracking Test
Contents:会计就业前景
Section 1 — Overview (2)
Section 2 — Apparatus (3)
Section 3 — Materials (5)
Section 4 — Specimen (6)
Section 5 — Procedure (7)
Section 6 — Report (9)
Section 7 — Report Forms (10)
Section 8 — Archived Versions (11)
Overview
单词发音
Effective date: November 2004 (refer to 'Archived Versions' for earlier versions).
U this test method to determine the premature failure susceptibility of bituminous
mixtures due to weakness in the aggregate structure, inadequate binder stiffness, or moisture damage and other factors including inadequate adhesion between the asphalt binder and aggregate. This test method measures the rut depth and number of pass to failure.
四级真题Units of Measurement
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The values given in parenthes (if provided) are not standard and may not be exact
mathematical conversions. U each system of units parately. Combining values from the two systems may result in nonconformance with the standard.
rrtingApparatus
U the following apparatus:
now什么意思♦Wheel-tracking Device
•An electrically powered device capable of moving a steel wheel with a diameter of
8 in. (203.6 mm) and width of 1.85 in. (47 mm) over a test specimen.
•The load applied by the wheel is 158 ± 5 lbs. (705 ± 22 N).
•The wheel must reciprocate over the test specimen, with the position varying sinusoidally over time.
freedom of speech•The wheel shall make approximately 50 pass across the test specimen per minute.
启德出国留学中介好吗•The maximum speed of the wheel must be approximately 1.1 ft./c. (0.305 m/s) and will be reached at the midpoint of the slab.
tickling
♦Temperature Control System
• A water bath capable of controlling the test temperature within ± 4°F (2°C) over a range of 77 to 158°F (25 to 70°C).
•This water bath must have a mechanical circulating system to stabilize temperature within the specimen tank.
♦Rut Depth Measurement System
• A Linear Variable Differential Transducer (LVDT) device capable of measuring the rut depth induced by the steel wheel within 0.0004 in. (0.01 mm), over a
minimum range of 0.8 in. (20 mm).
•The system shall be mounted to measure the rut depth at the midpoint of the wheel's path on the slab.
•Rut depth measurements must be taken at least every 100 pass of the wheel.
•This system must be capable of measuring the rut depth without stopping the wheel. This measurement must be referenced to the number of wheel pass.
•Fully automated data acquisition and test control system (computer included).
♦Wheel Pass Counter
• A non-contacting solenoid that counts each wheel pass over the test specimen.
•The signal from this counter must be coupled to the rut depth measurement, allowing the rut depth to be expresd as a fraction of the wheel pass.
♦Specimen Mounting System
• A stainless steel tray which can be mounted rigidly to the machine in the water bath.
•This mounting must restrict shifting of the specimen during testing.
•The system must suspend the specimen, allowing free circulation of the water bath on all sides.
疯狂用英语怎么说•The mounting system shall be designed to provide a minimum of 0.79 in. (2 cm) of free circulating water on all sides of the sample.
Section 3
Materials
U the following materials:
♦Three high-density polyethylene molds shaped according to plan view in the 'Top View of Test Spe
cimen Configuration for the Hamburg Wheel-Tracking Device' to cure circular, cylindrical test specimens. U one mold for cutting the specimen and the other two for performing the test.
♦Capping compound able to withstand 890 N (200 lb.) load without cracking.
