ESBD_490302_1771428934191_02. Specification No. TxDOT 845-49-51885.pdf

TEXAS DEPARTMENT OF TRANSPORTATION

SPECIFICATION NO.

TxDOT 845-49-51885

DATED: JANUARY 2026

1-4

LOADED WHEEL ASPHALT TESTING SYSTEM

PUBLICATION

This specification is a product of the Texas Department of Transportation (TxDOT). This specification may not be sold for profit or monetary gain. If this document is altered in any way, the header, and all references to TxDOT must be removed. TxDOT does not assume nor accept any liability when this specification is used in the procurement process by any other entity.

1. SCOPE: This specification is for the purchase of one (1) Loaded Wheel Asphalt Testing System for use by the Texas Department of Transportation (TxDOT), Materials and Tests Division.

2. DELIVERY LOCATION: The unit must be delivered to the Texas Department of Transportation, Materials and Tests Division 6230 E. Stassney Lane Austin, TX 78744. Attn: Benjamin Arras

3. DEFINITIONS OF TERMS AND ACRONYMS

3.1. AASHTO – American Association of Highway and Transportation Officials

3.2. LVDT - Linear Variable Differential Transducer

3.3. NCHRP - National Cooperative Highway Research Program

3.4. ANSI – American National Standard Institute

3.5. RMSE - Root Mean Square Error

4. EQUIPMENT

4.1. Equipment furnished must be the latest model in current production, as offered to commercial trade, and of quality workmanship and material. The vendor represents that all equipment offered will be new. Used, shopworn, demonstrator, prototype, re-manufactured, or discontinued models are not acceptable.

4.2. All parts not specifically mentioned which are necessary for the unit to be complete and ready for operation or which are normally furnished as standard equipment must be furnished by the vendor. All parts must conform in strength, quality, and workmanship to the accepted standard of the industry.

4.3. The equipment must meet all applicable federal and State of Texas safety, health, lighting, and noise standards that are in effect at the time of manufacture.

4.4. The equipment must meet all requirements of AASHTO T 324-23 – Standard Test Method for Hamburg Wheel-Tracking of Compacted Asphalt Mixtures (see Attachment A).

4.5. The equipment must meet all requirements of Tex-242-F – Test Procedure to Determine the Susceptibility of Bituminous Mixtures (see Attachment B).

4.6. Machine must be constructed from 300 series stainless steel or have a corrosion resistant coating to ensure longevity and no corrosion.

TxDOT 845-49-51885

DATED: JANUARY 2026

2-4

4.7. Equipment must be full-size, with a minimum overall width of 52 inches (1320.8 mm).

4.8. Equipment must include a winch for lifting the load arm or removable trays that eliminate the need to manually lift the loading arm.

4.9. Wheel travel speed must be approximately 1.0 ft./sec. (0.305 m/s) at the midpoint of the test specimen.

4.10. The wheel must reciprocate over the specimen in a sinusoidal pattern. The maximum deviation from the sinusoidal motion must not exceed a root mean square error (RMSE) of 2.54 mm across the entire track length, as defined by NCHRP Project 20-07/Task 361.

4.11. Equipment must include an enclosed chamber and air heating system capable of maintaining a consistent temperature during dry testing.

4.12. There must be no physical contact between the stainless-steel wheel and the specimen prior to test initiation.

4.13. Water tank must allow full access for cleaning and draining.

4.14. Water bath must include a mechanical circulation system to maintain stable temperature within the tank.

4.15. System must support calibration and verification of load cells, LVDTs, and temperature sensors.

4.16. Water bath must maintain test temperatures within ±4°F (2°C) across a range of 77–158°F (25–70°C).

4.17. Equipment must use a dual-wheel system with retractable wheels.

4.18. Wheel load must be 158 ±1 lb. (705 ±4.5 N), applied by direct weight, not pneumatic systems.

4.19. Each wheel must operate independently. Operation of one wheel must not interfere with the other or disturb the specimen.

4.20. Equipment must operate on single-phase electrical power.

5. SOFTWARE

5.1. Equipment must include a fully automated data acquisition and test control system. A computer must be provided.

5.2. Software must calculate average rut depth using the average of the three or five central rut measurements from each specimen.

5.3. Software must identify the stripping inflection point during the test.

5.4. Software must allow preconditioning time to be incorporated automatically, without user input.

5.5. Software must record rut depth at every 100-wheel passes.

5.6. System must measure rut depth continuously without requiring wheel stoppage.

Depth measurements must be linked to the number of passes.

DATED: JANUARY 2026

3-4

6. SAFETY PLAQUES OR DECALS

6.1. Safety plaques or decals must be included and placed at all machine locations where hazards are present.

6.2. Each plaque or decal must state the type of hazard, hazard severity, methods to avoid the hazard, and consequences of exposure.

6.3. Permanent plaques are preferred over decals.

6.4. Safety markings must meet the requirements of ANSI Z535.4 (latest revision) in terms of type, size, and placement.

7. INSTALLATION AND CALIBRATION:

The vendor must install the unit(s) at the designated TxDOT site and must ensure complete installation and calibration of the equipment. This includes providing calibration certificates and all cables, hoses, brackets, and accessories necessary for complete and safe installation, connection to power and telecommunications sources, and diagnostic testing.

The unit(s) must be fully operational upon completion. TxDOT will perform all physical modifications to the installation site, unless otherwise specified.

NOTE: Please include installation, calibration, and freight charges in the unit price of the bid tab.

8. EXAMPLE MAKE/MODELS

The Models are listed for reference only to show the expected type and quality. Equivalent equipment meeting or exceeding this specification will be considered in accordance with paragraph 2.01 of the TxDOT Terms and Conditions.

8.1. Instrotek – B038A SmarTracker

8.2. Cox&Sons – Hamburg Wheel Tracker

9. VENDOR DELIVERABLES

9.1. One Loaded Wheel Asphalt Testing System meeting all requirements of this specification.

9.2. Factory Trained Technician to perform, installation and calibration (no training required).

10. WARRANTY REQUIREMENTS

MATERIAL WARRANTY: Materials provided under the contract must be in current production, as offered to commercial trade, and be of quality material. Used, shopworn, demonstrator, prototype, reconditioned, or discontinued materials are not acceptable.

Materials must be warranted against material defects and defects in workmanship for a period of not less than 12 months and cover 100% parts and labor. The warranty period must commence upon date of acceptance by TxDOT. If the manufacturer’s standard warranty period exceeds 12 months, then the standard warranty period must be in effect.

The vendor must be responsible for the warranty. The vendor must provide the designated TxDOT representative with all manufacturers’ warranty documents upon completion of service prior to leaving the job site.

DATED: JANUARY 2026

4-4

11. VENDOR PERFORMANCE: Vendor performance will be monitored on a regular basis by TxDOT.

11.1. An unsatisfactory performance determination includes, but is not limited to:

11.1.1. Failure to deliver any portion of the equipment.

11.1.2. Any requirement not met as outlined in the equipment requirements determined by TxDOT.

NOTE: Unsatisfactory performance may result in a negative vendor performance report, or cancellation of the contract or both, in addition to any other rights, liquidated damages and remedies provided by the contract or allowed by law.

11.2. An exceptional performance determination includes, but is not limited to:

11.2.1. Deliverables made early upon TxDOT personnel request.

11.2.2. Product upgrade substitution suggested and accepted at no additional cost to TxDOT.

11.2.3. Vendor commended for exceptional customer service; exceptional service provided.

11.2.4. Provided technical assistance when not required.

51885

DATED: JANUARY 6

This test method describes a procedure for testing the rutting and moisture-susceptibility of asphalt mixture pavement samples in the Hamburg wheel-tracking device. � " � " The method describes the testing of a submerged, compacted asphalt mixture in a reciprocating rolling-wheel device. This test provides information about the rate of permanent deformation from a moving, concentrated load. A laboratory compactor has been designed to prepare slab specimens. Also, the Superpave Gyratory Compactor (SGC) has been designed to compact specimens in the laboratory. Alternatively, field cores having a diameter of 150 mm (6 in.), 250 mm (10 in.), or 300 mm (12 in.), or saw-cut slab specimens may be tested. � " � " The test method is used to determine the premature failure susceptibility of asphalt mixture due to weakness in the aggregate structure, inadequate binder stiffness, or moisture damage. This test method measures the rut depth and number of passes to failure. � " � " This test method measures the potential for moisture damage effects because the specimens are submerged in temperature-controlled water during loading. � " # " This test method is intended to be the standard; however, agencies may require deviations for various reasons, including test temperature, maximum rut depth calculation, equipment, or others.

Deviations must be documented and made available to any accreditation or certifying entities or stakeholders, such as contractors and material producers, upon request. �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�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

I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

� " � " A A f g % h f ) * + , * - , (

M 339M/M 339, Thermometers Used in the Testing of Construction Materials

R 18, Establishing and Implementing a Quality Management System for Construction

Materials Testing Laboratories

R 30, Mixture Conditioning of Asphalt Mixtures

R 97, Sampling Asphalt Mixtures

T 166, Bulk Specific Gravity ( i j k ) of Compacted Asphalt Mixtures Using Saturated Surface-

Dry Specimens

T 209, Theoretical Maximum Specific Gravity ( i j j ) and Density of Asphalt Mixtures

T 269, Percent Air Voids in Compacted Dense and Open Asphalt Mixtures

T 312, Preparing and Determining the Density of Asphalt Mixture Specimens by Means of the

Superpave Gyratory Compactor � " � " A f % l f ) * + , * - , (

D6027/D6027M, Standard Practice for Calibrating Linear Displacement Transducers for

Geotechnical Purposes

D8079, Standard Practice for Preparation of Compacted Slab Asphalt Mix Samples Using a

Segmented Rolling Compactor

E1, Standard Specification for ASTM Liquid!in!Glass Thermometers

E230/E230M, Standard Specification for Temperature!Electromotive Force (emf) Tables for

Standardized Thermocouples

E879, Standard Specification for Thermistor Sensors for General Purpose and Laboratory

Temperature Measurements

E1137/E1137M, Standard Specification for Industrial Platinum Resistance Thermometers

E2877, Standard Guide for Digital Contact Thermometers � " � " = + ) 3 - + * ) ' 1 + * 2 m 2 3 ; ) - 1 ) 3 ; & + ' ; * 2 n 1 . . ' ( ( ' 1 + f ) * + , * - , (

IEC 60584!1: 2013 Thermocouples ! Part 1: EMF Specifications and Tolerances

IEC 60751: 2008 Industrial Platinum Resistance Thermometers and Platinum Temperature

Sensors � " � " o * ) ' 1 + * 2 n 1 1 7 3 - * ) ' 0 3 g ' ? & < * / B 3 ( 3 * - ; & p - 1 ? - * .

NCHRP Web-Only Document 219, g * . > 5 - ? q & 3 3 2 r % - * ; s % 3 ( ) m 8 5 ' 7 . 3 + ) B 3 8 5 ' - 3 . 3 + ) ( * + ,= . 7 - 1 0 3 . 3 + ) ( ) 1 A A f g % h % t u v

. NCHRP Project 20-07/Task 361. National Cooperative

Highway Research Program, Transportation Research Board, Washington, DC, 2016.

Available from https://www.trb.org/Publications/Blurbs/173895.aspx; login required. � " � " This test measures the rutting and moisture susceptibility of an asphalt mixture specimen. � " � " A laboratory-compacted specimen of asphalt mixture, a saw-cut slab specimen, or a core taken from a compacted pavement is repetitively loaded using a reciprocating steel wheel. The specimen is submerged in a temperature-controlled water bath at a temperature specified by the agency. The deformation of the specimen, caused by the wheel loading, is measured. I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

The impression is plotted as a function of the number of wheel passes. An abrupt increase in the rate of deformation may coincide with stripping of the asphalt binder from the aggregate in the asphalt mixture specimen. # " � " g * . > 5 - ? q & 3 3 2 r % - * ; s ' + ? w 3 0 ' ; 3 —An electrically powered machine capable of moving a

203.2 ± 2.0-mm (8 ± 0.08-in.) diameter, 47 ± 0.5-mm (1.85 ± 0.02-in.) wide steel wheel over the center (x and axes) of the test specimen. The load on the wheel is 703 ± 4.5 N (158.0 ± 1.0 lb).

The wheel reciprocates over the specimen, with the position varying sinusoidally over time. A maximum level of deviation from a perfectly sinusoidal wave is defined through the root mean square error (RMSE), which is calculated as follows:

RMSE yz{

| C } where: 3 ~

= deviation from a pure sinusoidal curve, and + = number of data points.

The maximum allowable deviation from a sinusoidal wave through the entire track length is set at an RMSE of 2.54 mm (0.1 in.) unless otherwise specified by the agency. The wheel makes 52 ± 2 passes across the specimen per minute. The maximum speed of the wheel, reached at the midpoint of the specimen, is 0.305 ± 0.02 m/s (1 ± 0.066 ft/s). � � � � � —Verify the sinusoidal wave requirement of the Hamburg wheel-tracking device using a

Hamburg wheel-tracking device verification/calibration kit. # " � " % 3 . 7 3 - * ) 5 - 3 n 1 + ) - 1 2 f / ( ) 3 .

—A water bath capable of controlling the temperature within ±1.0°C

(1.8°F) over a range of 25 to 70°C (77 to 158°F) with a mechanical circulating system stabilizing the temperature within the specimen tank. The thermometer for measuring the temperature of the water bath shall meet the requirements of M 339M/M 339 with a temperature range of at least

20 to 75°C (68 to 167°F), and an accuracy of ±0.25°C (±0.45°F) (see Note 2). � � � � � —Thermometer types suitable for use include ASTM E1 mercury thermometers; ASTM

E879 thermistor thermometer; ASTM E1137/E1137M Pt-100 RTD platinum resistance thermometer, Class A; or IEC 60751: 2008 Pt-100 RTD platinum resistance thermometer, Class AA. # " � " = . 7 - 3 ( ( ' 1 + l 3 * ( 5 - 3 . 3 + ) f / ( ) 3 .

A linear displacement transducer (LDT) device capable of measuring the depth of the impression

(rut) of the wheel to within 0.15 mm (0.006 in.), over a minimum range of 0 to 20 mm

(0 to 0.8 in.). # " � " � " The system shall measure the depth of the impression at a minimum at the following locations along the track length: –114 (–4.5), –91 (–3.6), –69 (–2.7), –46 (–1.8), –23 (–0.9), 0 (0), +23 (+0.9), +46 (+1.8), +69 (+2.7), +91 (+3.6), and +114 (+4.5) mm (in.) with zero being the midpoint of the track unless otherwise specified by the agency. The midpoint of the track shall be marked by the manufacturer. # " � " � " The system measures the rut depth, without stopping the wheel, at least every 20 passes. Rut depth is expressed as a function of the wheel passes. The device will also disengage if the average LDT displacement (read from the micro-control unit, not the screen) is 40.90 mm (1.6 in.) or greater for an individual specimen. Note that the screen readout subtracts the initial LDT reading from the total displacement. I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

The maximum level of deviation from the 11 preset locations is defined through the RMSE, which is calculated as follows:

RMSE ���

| u } where: 3 ~ = deviation from the preset location after considering the effect of curvature of the aluminum apparatus (Table A1.1); and + = number of data points. # " � " # "

The maximum allowable RMSE at the 11 preset locations after considering the effect of curvature of the aluminum apparatus (Table A1.1), discussed in the NCHRP Web-Only Document 219, is

1.27 mm (0.05 in.). � � � � � —The locations of the deformation readings should be verified using the aluminum apparatus presented in Section A6.4. # " � " q & 3 3 2 p * ( ( n 1 5 + ) 3 - —A non-contacting solenoid that counts each wheel pass over the specimen.

The signal from this counter is coupled to the wheel impression measurement, allowing for the rut depth to be expressed as a function of the wheel passes. # " # " f 2 * > f 7 3 ; ' . 3 + l 1 5 + ) ' + ? f / ( ) 3 .

—A stainless steel tray that is mounted rigidly to the machine.

The mounting system must restrict shifting of the specimen to within 0.5 mm (0.02 in.) during testing and must suspend the specimen to provide a minimum of 20 mm (0.8 in.) of free circulating water on all sides of the mounting system. # " $ " n / 2 ' + , - ' ; * 2 f 7 3 ; ' . 3 + l 1 5 + ) ' + ? f / ( ) 3 .

—An assembly consisting of two high-density polyethylene (HDPE) molds or plaster of Paris, in accordance with Section 8 to secure the specimen (as shown in Figures 1 and 2), placed on a stainless steel tray that is mounted rigidly to the machine. This mounting system must restrict shifting of the specimen to within 0.5 mm

(0.02 in.) during testing and must suspend the specimen to provide a minimum of 20 mm (0.8 in.)

of free circulating water on all sides of the mounting system.

—Cylindrical Specimen Mounting System

I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

* Dimensions may vary depending on the manufacturer.� � � � � � � —Schematic of Cylindrical Specimen Mounting System# " @ " � ' + 3 * - � + 3 * , ' + ? n 1 . 7 * ; ) 1 -

—A hydraulic-powered unit that uses a series of vertically aligned steel plates to compact molded asphalt mixtures into flat, rectangular slabs of predetermined thickness and density.# " � " h 0 3 + ( —For heating aggregate and asphalt binders to their appropriate mixing temperature.

Oven(s) for heating shall be properly standardized and capable of operation at the temperatures required, between 100 to 175°C (212 to 347°F), within ±5°C (±9°F), as corrected, if necessary, by calibration. More than one oven may be used, provided each is used within its proper operating temperature range. The thermometer for measuring the temperature of materials shall meet the requirements of M 339M/M 339 with a temperature range of at least 140 to 175°C (284 to 347°F), and an accuracy of ±1.25°C (±2.25°F) (see Note 4).� � � � � —Thermometer types suitable for use include ASTM E1 mercury thermometers; ASTM

E230/E230M thermocouple thermometer, Type T, Special Class; or IEC 60584 thermocouple thermometer, Type T, Class 1.# " � " f 5 7 3 - 7 * 0 3 i / - * ) 1 - / n 1 . 7 * ; ) 1 - | f i n } —And molds conforming to T 312.# " � � "

Bowls, spoon, spatula, etc. $ " � " o 5 . > 3 - 1 : % 3 ( ) f 7 3 ; ' . 3 + ( —Prepare two test specimens for each test, either slab specimens or cylinders.$ " � " � * > 1 - * ) 1 - / r p - 1 , 5 ; 3 , A ( 7 & * 2 ) l ' x ) 5 - 3

Batch mixture proportions in accordance with the desired job mix formula.I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

Use the mixing temperature at which the asphalt binder achieves a viscosity of 170 ± 20 cSt. For modified asphalt binders, use the mixing temperature recommended by the binder manufacturer. $ " � " � " Dry-mix the aggregates and mineral admixture (if used) first, then add the correct percentage of asphalt binder. Mix the materials to coat all aggregates thoroughly. (Wet-mix the aggregates if using a lime slurry or other wet material.) $ " � " � " Condition test samples at the appropriate compaction temperature in accordance with the short-term conditioning procedure for mechanical properties in R 30. $ " � " # " Use the compaction temperature at which the asphalt binder achieves a viscosity of 280 ± 30 cSt.

For modified asphalt binders, use the compaction temperature recommended by the binder manufacturer. $ " � " $ " � * > 1 - * ) 1 - / n 1 . 7 * ; ) ' 1 + 1 : f 7 3 ; ' . 3 + ( —Compact either slab specimens or SGC cylindrical specimens. $ " � " $ " � " n 1 . 7 * ; ) ' + ? f 2 * > f 7 3 ; ' . 3 + ( —Heat molds and tools to compaction temperature. Compact slab specimens 320 mm (12.5 in.) long and 260 mm (10.25 in.) wide using a Linear Kneading

Compactor (or equivalent such as a compactor meeting ASTM D8079). Specimen thickness must be at least twice the nominal maximum aggregate size, generally yielding a specimen 38 to

100 mm (1.5 to 4 in.) thick. Allow compacted slab specimens to cool at normal room temperature on a clean, flat surface until cool to the touch. $ " � " $ " � " n 1 . 7 * ; ) ' + ? f i n n / 2 ' + , - ' ; * 2 f 7 3 ; ' . 3 + ( —Compact two 150-mm (6-in.) diameter specimens in accordance with T 312. Specimen thickness must be at least twice the nominal maximum aggregate size, generally yielding a specimen 38 to 100 mm (1.5 to 4 in.) thick. Allow compacted specimens to cool at normal room temperature on a clean, flat surface until cool to the touch. $ " � " � ' 3 2 , r p - 1 , 5 ; 3 , A ( 7 & * 2 ) l ' x ) 5 - 3 � � 1 1 ( 3 l ' x : $ " � " � " Obtain a sample of asphalt mixture in accordance with R 97. $ " � " � " � * > 1 - * ) 1 - / n 1 . 7 * ; ) ' 1 + 1 : f 7 3 ; ' . 3 + (

—Compact either slab specimens or SGC cylindrical specimens in accordance with Section 6.2.6. $ " � " � ' 3 2 , r p - 1 , 5 ; 3 , A ( 7 & * 2 ) l ' x ) 5 - 3 � � ' 3 2 , n 1 . 7 * ; ) 3 , | n 1 - 3 F f 2 * > f 7 3 ; ' . 3 + } : $ " � " � " n 5 ) ) ' + ? � ' 3 2 , n 1 - 3 ( 1 - � ' 3 2 , f 2 * > f 7 3 ; ' . 3 + (

—Field cores or field slab specimens consist of wet saw-cut compacted specimens taken from asphalt mixture pavements. Cut field cores 300 mm

(12 in.), 250 mm (10 in.), or 150 mm (6 in.) in diameter. Cut field slab specimens approximately

260 mm (10.25 in.) wide by 320 mm (12.5 in.) long. Use a slab specimen thickness of 38 to

100 mm (1.5 to 4 in.). The height of a field core or field slab specimen is typically 38 mm (1.5 in.)

but may be adjusted to fit the specimen mounting system by wet saw-cutting. Cut field cores in accordance with Section 6.4.2. � � � � � —Take care to load the sample so it is level to the surface of the mold. Trim the sample if it is too tall or use shims if it is too short (supporting with plaster if needed). Calibrate the down pressure from the wheel to be 703 ± 4.5 N (158.0 ± 1.0 lb.) at the center, level to the top of the mold position. Even a small change in elevation will change the down pressure significantly. $ " � " � " n 5 ) ) ' + ? f i n n / 2 ' + , - ' ; * 2 f 7 3 ; ' . 3 + ( * + , � ' 3 2 , n 1 - 3 ( —Cut specimens after they have cooled to room temperature using a wet or dry saw. Saw the specimens along equal secant lines (or chords) such that when joined together in the molds, there is no space between the cut edges. The amount of material sawed from the SGC cylindrical specimens may vary to achieve a gap width no greater than 7.5 mm (0.3 in.) between the molds. I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

—To cut specimens consistently may require the use of a jig. @ " � "

Determine the bulk specific gravity of the specimens in accordance with T 166. @ " � " Determine the maximum specific gravity of the mixture in accordance with T 209. @ " � " Determine the air void content of the specimens in accordance with T 269. The recommended target air void content is 7.0 ± 0.5 percent for laboratory-compacted SGC cylindrical specimens and 7.0 ± 1.0 percent for laboratory-compacted slab specimens. Field specimens may be tested at the air void content at which they are obtained. � " � " f 2 * > * + , � * - ? 3 � ' 3 2 , n 1 - 3 f 7 3 ; ' . 3 + l 1 5 + ) ' + ?

—Use plaster of Paris to rigidly mount the

300 mm (12 in.), 250 mm (10 in.), or slab specimens in the mounting trays. Mix the plaster at approximately a 1:1 ratio of plaster to water. Pour the plaster to a height equal to that of the specimen to fill the air space between the specimen and the sides of the mounting tray. The slab specimen will be in direct contact with the mounting tray; however, plaster may flow underneath the specimen. If the thickness of the Slab or Large Field Core Specimen is the same as the height of the mounting tray, the plaster underneath the specimen must not exceed 2 mm (0.08 in.). If the thickness of the Slab or Large Field Core Specimen is less than the height of the mounting tray, plaster and/or shims from aluminum, HDPE, or other suitable material shall be used underneath the specimen as necessary to bring the top of the specimen level with the top of the mounting tray and to prevent any movement of the specimen in the mounting tray during testing. Allow the plaster at least 1 h to set. If using other mounting material, it should be able to withstand 890 N

(200 lb) of load without cracking. � " � " f i n n / 2 ' + , - ' ; * 2 * + , � ' 3 2 , n 1 - 3 f 7 3 ; ' . 3 + l 1 5 + ) ' + ?

—Rigidly mount the 150-mm [5.91-in.] or

152-mm [6-in.] diameter samples in the mounting tray using HDPE molds meeting the dimensions outlined in Figure 2 or use plaster of Paris. For HDPE molds, place the molds in the mounting tray and insert the cut specimens in the molds. Shim the molds in the mounting tray as necessary.

Secure the molds into the mounting tray. If plaster of Paris is used, pour the plaster to a height equal to that of the specimen to fill the air space between the specimen and the sides of the mounting tray. The specimen will be in direct contact with the mounting tray; however, plaster may flow underneath the specimen. For SGC Cylindrical Specimens the plaster underneath the specimen must not exceed 2 mm (0.08 in.) in thickness. For Field Core Specimens plaster and/or shims from aluminum, HDPE, or other suitable material shall be used underneath the specimen as necessary to bring the top of the specimen level with the top of the HDPE molds and to prevent any movement of the specimen in the molds during testing. Allow the plaster at least 1 h to set. � � � � � —Cores drilled with a 152-mm [6-in.] drill bit may not fit in the 150-mm [5.91-in.] HDPE mold and may require further trimming and mounting in plaster of Paris. � " � " Place the mounting tray(s) with the test specimens into the device. Adjust the height of the specimen tray as recommended by the manufacturer, and secure by hand-tightening the bolts. � " � " Turn the testing device and all components on. � " # " Start the software used to communicate with the testing device.� " $ " Enter the pertinent project information and testing configuration requirements.

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Select the test temperature based on the applicable specifications. � " $ " � " Select the maximum allowable rut depth based on the applicable specifications. � " $ " � " Select the maximum number of passes based on the applicable specifications. � " $ " � " Enter a start delay of 45 min to precondition the test specimens. The temperature of the specimens in the mounting tray will be the test temperature selected in Section 8.6.1 on completion of this preconditioning period. � " @ " Proceed to Section 8.8 to operate the testing device in “Auto” mode. Proceed to Section 8.9 to operate the testing device in “Manual” mode. � � � � � —Perform the test in “Auto” mode for testing devices manufactured in the United States later than 1998, where software will automatically open and close the valves to fill and drain the water bath. Perform the test in “Manual” mode for devices made available to the United States prior to 1998. � " � " p 3 - : 1 - . ' + ? ) & 3 % 3 ( ) ' + A 5 ) 1 l 1 , 3

Adjust the height of the LDT in accordance with the manufacturer’s recommendations. � � � � � —The LDT for each steel wheel is automatically zeroed at the start of the test. The software will display a zero at the start of the test. � " � " � " If using cylindrical specimens, lower the wheels onto the edge of the test specimens such that a majority of the wheel is in contact with the HDPE molds in the mounting tray. If using slabs, lower the wheels onto the specimen no more than 5 min prior to the beginning of the test. In either case, the sample must not be submerged longer than 60 ± 5 min prior to starting the test. This includes the conditioning time. � " � " � " Start the test by selecting the “Start” button of the testing device software. � � � � � �

—The start delay time or preconditioning time will start after the water heats to the test temperature selected in Section 8.6.1. � " � " � " The wheel-tracking device will stop when 20,000 passes have occurred, when some other predetermined number of passes has occurred, or when the test has achieved the maximum impression depth established in Section 8.6.2. The testing device software automatically saves the test data file. � " � " # " Raise the wheel(s) and remove the specimen mounting tray(s) and rutted specimens. � " � " $ " Proceed to Section 8.10. � " � " p 3 - : 1 - . ' + ? ) & 3 % 3 ( ) ' + l * + 5 * 2 l 1 , 3

Close the drain valve(s) and fill the water bath of the wheel-tracking device with water until the float device(s) raises to a horizontal position. � � � � � � —Adjust the amount of hot and cold water if necessary, as the water temperature may vary. � " � " � " Precondition the test specimens in the water bath for 45 min after the water has reached the selected test temperature. Do not place the sample in the conditioning bath more than

60 ± 5 min prior to beginning the test. This includes the preconditioning time.

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Lower the wheels onto the specimens after the test specimens have preconditioned at the selected test temperature for 45 min. For machines that start automatically after the selected preconditioning time, it is allowable to lower the wheels before the preconditioning cycle. The wheel must not be in contact with the specimen for more than 5 min prior to starting the wheel. � " � " � " Ensure the micro-control unit’s LDT reads between 10 and 18 mm (0.4 and 0.7 in.). Adjust the

LDT height to obtain this reading. Loosen the two screws on the LDT mount and slide the LDT up or down to the desired height. Tighten the screws. � " � " # " Start the test. � " � " $ " The wheel-tracking device will stop when 20,000 passes have occurred, when some other predetermined number of passes has occurred, or when the test has achieved the maximum impression depth established in Section 8.6.2. � " � " @ " Open the valve(s) beneath the tanks and drain the water bath. Raise the wheel(s) and remove the specimen mounting tray(s) and rutted specimens. � " � � " Clean the water bath, heating coils, wheels, and temperature probe with water and scouring pads or per the manufacturer’s recommendations. Use a wet-dry vacuum to remove particles that have settled to the bottom of the baths. Clean the filter element and spacers after every test or per the manufacturer’s recommendations. Do not use solvents to clean the water bath. � " � � " Turn the wheels after each test, so the same section of the wheel surface is not in contact with the test specimen from test to test. This rotation will provide for even wear over the entire wheel. The test should operate with a smooth movement across the test specimen. � " � " � 1 - ) & 3 7 5 - 7 1 ( 3 ( 1 : ) & ' ( . 3 ) & 1 , 6 * � ) 3 ( ) � ' ( , 3 : ' + 3 , * (

Two 320-mm (12.5-in.) long by 260-mm (10.25-in.) wide slab specimens, two 250-mm

(10-in.) diameter core specimens, or two 300-mm (12-in.) diameter core specimens representing similar material run in the Hamburg wheel-tracking device simultaneously; or � " � " � " Four 150-mm (6-in.) diameter cylindrical or core specimens grouped in pairs (1 and 1a) representing similar material run in the Hamburg wheel-tracking device simultaneously. � " � " The test results will be reported as the average value of both specimens (a) or both pairs of specimens (b). Alternatively, the specifying agency may choose to define a “test” as a single slab or core specimen or as a pair of 150-mm (6-in.) diameter cylindrical specimens. � " � " The maximum rut depth shall be calculated based on the average rut depth for the five middle deformation locations (i.e., located at –46 (–1.8), –23 (–0.9), 0, +23 (+0.9), and

+46 (+1.8) mm (in.)) or other suitable method as specified by the agency. Plot the rut depth versus number of passes for each test for each deformation location. � " � " Figure 3 shows a typical plot of the output produced by the Hamburg wheel-tracking device. From this plot, obtain the following values: � " � " � " Slope and intercept of the first steady-state portion of the curve, and � " � " � " Slope and intercept of the second steady-state portion of the curve.

I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

—Hamburg Curve with Test Parameters � " # "

Calculate the following test parameters, all expressed in “Passes.”

intercept (second portion) – intercept (first portion) stripping inflection point (SIP) = slope (first portion) – slope (second portion)

| t } where failure rut depth is the specified maximum allowable rut depth for the test. � � � � � � —The specifying agency may choose to define a “test” as an individual slab or core specimen or as a pair of specimens as defined in Section 9.1. � � " � " % & 3 - 3 7 1 - ) . * / ' + ; 2 5 , 3 ) & 3 : 1 2 2 1 < ' + ? 7 * - * . 3 ) 3 - (

Asphalt mixture production (field or lab); � � " � " � " Compaction method (slab or SGC cylindrical specimen); � � " � " � " Number of passes at maximum impression; � � " � " � " Maximum impression; � � " � " # " Test temperature; � � " � " $ " Specimen(s) air voids; � � " � " @ " Type and amount of anti-stripping additive used; � � " � " � " Creep slope; � � " � " � " Strip slope; and I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

Stripping inflection point. � � " � " Work is underway to develop precision and bias statements for this standard. � � " � " Compacted asphalt mixture; moisture-susceptibility; rutting; wheel-track testing.

(Mandatory Information) � � " � " This Annex covers the evaluation of the Hamburg wheel-tracking device as a check for compliance with the requirements outlined in Sections 5.1 and 5.2. Included are measurements of the wheel!s diameter and width, visual inspection of critical surface conditions, verification of the water bath temperature, LDT calibration, wheel loading assembly, wheel travel, and rut measurement. � � " � " Minimum frequency of this evaluation is 12 months, except for water bath temperature, which is

6 months. � � " � " l 3 * ( 5 - 3 . 3 + ) = + ( ) - 5 . 3 + ) | n * 2 ' 7 3 - ( 1 - l ' ; - 1 . 3 ) 3 - } —With appropriate range and a minimum resolution of 0.1 mm (0.004 in.). The measurement instrument shall be standardized annually. � � " � " B 3 : 3 - 3 + ; 3 % & 3 - . 1 . 3 ) 3 - —With a minimum range of 25 to 70°C (77 to 158°F) with a minimum resolution of 0.1°C (± 0.2°F) and accurate to ± 0.5°C (± 0.9°F). � � " � " g * . > 5 - ? q & 3 3 2 r % - * ; s ' + ? w 3 0 ' ; 3 � 3 - ' : ' ; * ) ' 1 + F n * 2 ' > - * ) ' 1 + � ' ) —Containing equipment necessary to complete all measurements in Section A6. � � � � � � —Calibration kits are available from several equipment manufacturers.

� � " � " p 3 - : 1 - . * 0 ' ( 5 * 2 ' + ( 7 3 ; ) ' 1 + 1 : ) & 3 < & 3 3 2 : The wheel shall be free of residue and deep gouges.

Identify any wear that may be visible on the wheel. � � " � " Determine the maximum diameter of the wheel by measuring it at several locations. Place a removable mark at the maximum diameter position. Record the maximum diameter to the nearest

0.1 mm (0.004 in.).

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Measure the diameter at a 90-degree orientation to the maximum diameter. Record this diameter to the nearest 0.1 mm (0.004 in.). � � " � " Each individual diameter measurement shall be compared to the specified range and given a pass/fail rating. If any of the individual measurements are assigned a “fail” rating, the wheel is considered to be out of conformance and shall not be used. � � " � " p 3 - : 1 - . * 0 ' ( 5 * 2 ' + ( 7 3 ; ) ' 1 + 1 : ) & 3 < & 3 3 2 2 1 * , ' + ? ( 5 - : * ; 3 : The edge shall be free of residue and deep gouges. Identify any wear that may be visible on the edge of the wheel. � � " � " Determine the maximum width of the wheel by measuring it at several locations. Place a removable mark at this position. Record the maximum width to the nearest 0.1 mm (0.004 in.). � � " � " Measure the width at a 90-degree, 180-degree, and 270-degree orientation to the maximum width.

Record each width to the nearest 0.1 mm (0.004 in.). � � " � " Each individual width measurement shall be compared to the specified range and given a pass/fail rating. If any of the individual measurements is assigned a “fail” rating, the wheel is considered to be out of conformance and shall not be used. � # " � " Verify the water bath temperature is within ±1.0°C (±1.8°F) of the temperature readout from the testing device or software every 6 months. � # " � " Measure the water bath temperature at four locations per the manufacturer’s recommendations. � # " � " Average the four measurements and report this as the water bath verification temperature. � $ " � " Verify the LDT calibration in accordance with ASTM D6027/D6027M or per the manufacturer’s recommendations. � $ " � " Verify the load from the wheel loading assembly at the level of the initial height of the test per the manufacturer’s recommendations to be 703 ± 4.5 N (158.0 ± 1.0 lb). A calibrated load cell, accurate to 0.4 N (0.1 lb), is sufficient for this check. Align the center of the load cell with the middle of the wheel width as well as the center axis of the wheel. � $ " � " Verify that the wheel is reciprocating on the test sample at 52 ± 2 passes per min. � $ " � " Verify that rut measurements are obtained at the 11 preset locations defined in Section 5.2.1 using the aluminum apparatus presented in Figure A1.1. The maximum allowable RMSE at the 11 preset locations after considering the effect of curvature of the aluminum apparatus (Table A1.1) discussed in NCHRP Web-Only Document 219 is 1.27 mm (0.05 in.). � $ " # " The wheel position varying sinusoidally over time shall be verified to have a maximum RMSE of

2.54 mm (0.1 in.) from a perfectly sinusoidal wave unless otherwise specified by the agency.

I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

—Offset Values for Displacement Readings

Position (in.) Position (mm) Offset (mm)

–4.5 –114 0.79

–3.6 –91 0.50

–2.7 –69 0.28

–1.8 –46 0.13

–0.9 –23 0.03

0.0 0 0.00

0.9 23 0.03

1.8 46 0.13

2.7 69 0.28

3.6 91 0.50

4.5 114 0.79

—Details of the Metal Specimen� @ " � " B 3 ; 1 - , * + , - 3 7 1 - ) ) & 3 : 1 2 2 1 < ' + ? ' + : 1 - . * ) ' 1 +

Name of evaluator.� @ " � " Date. � @ " � " Equipment owner. � @ " # " Location of evaluation. � @ " $ " Hamburg wheel-tracking device. � @ " @ " Diameter measurements of the wheel to the nearest 0.1 mm (0.004 in.). I J K J L M N O P Q R S Q T U V W X R Y Y Z V U W O U Z X Z [ \ O W O Q ] U ^ P _ W N W X ` a T W X Y b Z T O W O U Z X c [ [ U V U W d Y e

Width of the loading surface of the wheel to the nearest 0.1 mm (0.004 in.). � @ " � " Water bath temperature to the nearest 0.1°C (0.1°F). � @ " � � "

LDT. � @ " � � "

Wheel assembly load reading to the nearest 0.1 N (0.1 lb.). � @ " � � " Wheel travel (passes per min.). � @ " � � " RMSE at the 11 preset locations after taking into account the effect of curvature of the aluminum apparatus to the nearest 0.01 mm (0.004 in.). � @ " � � " Deviation from a perfectly sinusoidal wave as defined through the RMSE to the nearest 0.01 mm

(0.004 in.). � @ " � # " Allowable maximum deviation from a perfectly sinusoidal wave as defined through the RMSE to the nearest 0.01 mm (0.004 in.) unless equal to 2.54 mm (0.1 in.).

(Nonmandatory Information) � � " � " Grease all of the grease fittings with fresh grease every 20 tests (not to exceed 2 months) per the manufacturer’s recommendations.

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HAMBURG WHEEL-TRACKING TEST

TXDOT DESIGNATION: TEX-242-F

MATERIALS AND TESTS DIVISION 1 – 7 EFFECTIVE DATE: JULY 2021

Test Procedure for

HAMBURG WHEEL-TRACKING TEST

TxDOT Designation: Tex-242-F

Effective Date: July 2021

1. SCOPE

1.1 This test method determines 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.

1.2 The values given in parentheses (if provided) are not standard and may not be exact mathematical conversions. Use each system of units separately. Combining values from the two systems may result in nonconformance with the standard.

2. APPARATUS

2.1 Wheel-Tracking Device—an electrically powered device capable of moving a steel wheel with a diameter of 8 ± 0.08 in. (203.2 ± 2.0 mm) and width of 1.85 in. (47 mm) over a test specimen.

2.1.1 The load applied by the wheel must be 158 5 lb. (705 22.2 N).

2.1.2 The wheel must reciprocate over the test specimen, with the position varying sinusoidally over time.

2.1.3 The wheel must be capable of making 52 ± 2 passes across the test specimen per minute.

2.1.4 The wheel must reach maximum speed, approximately 1.0 ft./sec. (0.305 m/s), at the midpoint of the combined specimens.

2.2 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).

2.2.1 The water bath must have a mechanical circulating system to stabilize temperature within the specimen tank.

2.3 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).

2.3.1 The system should measure the rut depth at 11 different locations in the wheel's path on the specimens as shown in Figure 1.

Attachment B SPECIFICATION NO.

DATED: JANUARY 2026

HAMBURG WHEEL-TRACKING TEST TXDOT DESIGNATION: TEX-242-F

MATERIALS AND TESTS DIVISION 2 – 7 EFFECTIVE DATE: JULY 2021

Figure 1—Schematic of Rut Depth Measurement Points

2.3.2 The system must take rut depth measurements at least every 100 passes of the wheel.

2.3.3 The system must be capable of measuring the rut depth without stopping the wheel. Reference this measurement to the number of wheel passes.

2.3.4 The system must have a fully automated data acquisition and test control system (computer included).

2.4 Wheel Pass Counter—a non-contacting solenoid that counts each wheel pass over the test specimen.

2.4.1 Couple the signal from this counter to the rut depth measurement, allowing the rut depth to be expressed as a fraction of the wheel passes.

2.5 Specimen Mounting System—a stainless steel tray that can be mounted rigidly to the machine in the water bath.

2.5.1 This mounting must restrict shifting of the specimen during testing.

2.5.2 The system must suspend the specimen, allowing a minimum of 0.79 in. (20 mm) of free circulating water on all sides of the mounting system.

2.6 Masonry Saw.

3. MATERIALS

3.1 Three high-density polyethylene molds, to secure circular, cylindrical test specimens. Use one mold for cutting the specimen, as shown in Figure 2, and the other two for performing the test, as shown in Figure 3.

3.2 Capping compound, able to withstand 890 N (200 lb.) load without cracking.

MATERIALS AND TESTS DIVISION 3 – 7 EFFECTIVE DATE: JULY 2021

Figure 2—Schematic of Specimen Cutting Setup

Figure 3—Top View of Test Specimen Configuration for the Hamburg Wheel-Tracking Device

4. SPECIMENS

4.1 Laboratory-Molded Specimens—Prepare two specimens in accordance with Tex-241-F. Specimen diameter must be 150 mm (5.9 in.), and height must be 62 ± 1 mm (2.40 ± 0.04 in.).

4.1.1 Density of test specimens must be 93 ± 0.5%, except for Permeable Friction Course (PFC) mixtures, Thin Bonded Wearing Course (TBWC), and Crack Attenuating Mix (CAM).

Note 1—Mixture weights for laboratory-molded specimens that achieve the density requirement typically vary between 2,400 and 2,600 g.

https://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit241.pdf

MATERIALS AND TESTS DIVISION 4 – 7 EFFECTIVE DATE: JULY 2021

4.1.2 For PFC mixtures, mold test specimens to 50 gyrations (Ndesign).

Note 2—Mixture weights for laboratory-molded PFC specimens that achieve the required specimen height at Ndesign typically vary between 2,000 and 2,200 g.

4.1.3 For TBWC mixtures, mold test specimens to 50 gyrations (Ndesign).

Note 3—Mixture weights for laboratory-molded TBWC specimens that achieve the required specimen height at Ndesign typically vary between 2,200 and 2,600 g.

4.1.4 For CAM mixtures, mold test specimens to 95 ± 0.5% density.

Note 4— Mixture weights for laboratory-molded specimens that achieve the density requirement typically vary between 2,400 and 2,600 g.

4.2 Core Specimens—Specimen diameter must be 145 ± 5 mm (5.7 ± 0.2 in.). There is not a specific density requirement for core specimens.

Note 5—Use a 6-in. nominal core bit (outside diameter) to sample cores for this test.

5.

5.1

5.1.1

5.1.2

5.1.3

5.1.4

5.2

5.2.1

5.2.2

5.2.3

PROCEDURE

Laboratory-Molded Mixtures:

Mold two specimens in accordance with Section 4.

Calculate the density of the specimens in accordance with Tex-207-F and Tex-227-F.

Note 6—Calculate the bulk specific gravity (Ga) of PFC specimens using dimensional analysis in accordance with Tex-207-F, Part VIII.

Allow the specimens to stand at room temperature (75 ± 5°F) for a minimum of 24 hr. before testing.

Test laboratory-molded specimens within three days of molding.

Roadway Cores:

Trim the bottom of the core to remove unwanted paving layers.

For cores greater than 64 mm (2.5 in.) in height, trim the bottom of the core to achieve a 62 ± 1 mm (2.40 ±

0.04 in.) total core height.

For cores less than 60 mm (2.4 in.) in height:

mix capping compound, place the core with surface facing downward in a 6-in. diameter plastic mold, spread the capping compound on top of the core to achieve a 62 ± 1 mm (2.40 ± 0.04 in.) total core height, allow the capping compound to dry for a minimum of 24 hr., and remove the plastic mold from the capped core.

5.3 Place a prepared specimen in the cutting template mold. Ensure the sample is pushed to the back of the template mold, and use a masonry saw to cut it along the flat edge of the mold as shown in Figure 2.

5.3.1 The cut across the specimen should be approximately 13 mm (1/2 in.) deep.

https://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit207.pdf https://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit227.pdf https://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit207.pdf

MATERIALS AND TESTS DIVISION 5 – 7 EFFECTIVE DATE: JULY 2021

5.4 Place the high-density polyethylene molds into the mounting tray and fit specimens into each one.

5.4.1 For cores less than 150 mm (5.9 in.) in diameter, place plastic spacers around the cores to secure them.

5.5 Ensure that the samples are firmly seated together and that there are no gaps at their interface. Fasten the mounting trays into the empty water bath by hand tightening the mounting hardware.

5.6 Start the software supplied with the machine, and enter the specimen or core…