AASHTO T 404-2023
Evaluation of the Tracking Resistance of Hot-Poured Asphalt Crack Sealant by Dynamic Shear Rheomete (DSR)
- Standard No.
- AASHTO T 404-2023
- Release Date
- 2023
- Published By
- American Association of State Highway and Transportation Officials US / AASHTO
- Latest
- AASHTO T 404-2023
- Introduction
Standard Overview and Technical Background
AASHTO T 404-23, "Standard Test Method for Tracking Resistance of Hot-Poured Asphalt Crack Sealant Adhesives by Dynamic Shear Rheometry," was first published as a full standard in 2023. It was formerly known as AASHTO Provisional Standard TP 126. Developed by Technical Subcommittee 4e (Joints and Bearings), this standard aims to establish a quantitative evaluation system for the tracking and deformation resistance of hot-poured asphalt crack sealants under high summer temperatures.
Test Principle and Rheological Foundation
This standard, based on the Ostwald-de Waele power-law model, uses a dynamic shear rheometer to determine two key rheological parameters of hot-poured asphalt crack sealants: the flow coefficient C and the shear thinning exponent P. During the test, the sealant sample underwent eight creep-recovery cycles with increasing stress levels (25Pa to 3200Pa) between parallel plates, and a rheological property model was established by analyzing the relationship between the limiting shear rate and stress.
Test parameters Technical requirements Engineering significance Test temperature range 46°C to 82°C Simulates the maximum summer temperature of actual road surfaces Apparent viscosity range 0.1-100 kPa·s Typical working conditions of covering sealant Specimen specifications Diameter 25mm, thickness 2.0mm Ensure comparability of test results Stress increase sequence 25, 50, 100, 200, 400, 800, 1600, 3200Pa Comprehensive characterization of nonlinear rheological behavior Key equipment and technical requirements
The core of the test system is a dynamic shear rheometer that meets the requirements of T 315, equipped with 25mm parallel test plates, environmental chamber, loading device and data acquisition system. Auxiliary equipment includes a standardized freezer that can maintain -23°C±2°C, and a temperature measuring device that meets the requirements of M 339M/M 339.
Application Case: A provincial highway maintenance department used the T 404-23 standard to evaluate the anti-tracking performance of sealants with different formulations. The test found that the shear thinning index P value of the polymer modified sealant was 0.65, significantly better than the 0.82 of ordinary asphalt-based sealants, and showed better anti-rutting and anti-tracking capabilities in actual use.
Detailed explanation of the test process
The specimen preparation strictly follows ASTM D5167. The homogenized hot-pouring sealant is injected into the mold and frozen at -23°C for 10 minutes to minimize the molecular association (spatial hardening) effect. During the test, each stress level is subjected to a cycle of 2 seconds of creep followed by 18 seconds of recovery. A 180-second equilibrium period is set between adjacent cycles to ensure thermal equilibrium.
Process stages Key technical requirements Quality control points Specimen preparation 500g homogenization, -23°C freezing Ensure consistent thermal history of specimens Instrument setup 25mm parallel plates, zero gap calibration Temperature control accuracy ±0.1°C 8-level stress increase, 20-second cycle per level Data acquisition frequency meets calculation requirements Data Processing Double-logarithmic coordinate fitting of a power-law equation Averaging of repeated sample results Engineering Significance of Key Parameters
The flow coefficient C (kPa·s) reflects the sealant's basic viscosity; larger values indicate greater resistance to flow. The shear-thinning exponent P (dimensionless) characterizes a material's sensitivity to shear rate. Lower P values (close to 0) indicate a more pronounced shear-thinning effect. A P value of 1 indicates Newtonian fluid behavior.
Technology evolution analysis: Compared with traditional empirical evaluation methods, T 404-23 systematically applies rheological principles to the evaluation of sealant anti-tracking performance for the first time. By quantifying the parameters C and P, objective comparison of material properties and formulation optimization are achieved, which promotes the transformation of sealants from empirical formulation to performance-oriented design.
Precision control and quality assurance
The standard stipulates strict single-operator precision requirements: the coefficient of variation of the flow coefficient C shall not exceed 10%, and the shear thinning index P must also meet the corresponding precision standards. Laboratories need to establish a quality management system that meets the requirements of R 18 to ensure the reliability and comparability of test results.
Quality control link Standard requirements Implementation recommendations Equipment calibration According to T 315 Perform DSR Verification Establish a regular calibration plan Temperature control Freezer -23°C±2°C, DSR±0.1°C Use certified temperature sensors Operating specifications Double sample repeated testing Train operators in standardized techniques Data reporting C values accurate to 0.1 kPa·s, P values to 0.01 Establish a standardized report template Recommendations for standard implementation
Users are advised to use T 404-23 in conjunction with related standards: M 338 for sealant performance grading, R 95 for accelerated aging evaluation, T 368/369/370 are used for low-temperature performance testing. In actual engineering applications, the appropriate test temperature should be selected based on local climatic conditions, usually corresponding to the 7-day maximum average road surface temperature.
For sealant manufacturers, it is recommended to establish a formulation optimization process based on T 404-23. By systematically testing the effects of different polymer modification systems and filler ratios on C and P values, products with excellent anti-tracking properties can be developed. For engineering users, test results can be used as an important basis for material selection and acceptance to ensure the long-term performance of road sealing projects.
Technological Development Trends
With the advancement of rheological testing technology and the development of materials science, future sealant evaluation standards may expand to more complex conditions such as multiple stress levels and variable temperature testing, and more accurate correlation models with actual road performance can be established. At the same time, data analysis technology based on artificial intelligence is expected to further improve testing efficiency and result reliability.
AASHTO T 404-2023 Referenced Document
- AASHTO M 338 Standard Specification for Performance-Graded Hot-Poured Asphalt Crack Sealant
- AASHTO M 339M/M 339 Standard Specification for Thermometers Used in the Testing of Construction Materials*， 2024-05-19 Update
- AASHTO R 116 Grading or Verifying the Sealant Grade (SG) of a Hot-Poured Asphalt Crack Sealant
- AASHTO R 18 Establishing and Implementing a Quality Management System for Construction Materials Testing Laboratories
- AASHTO R 95 Standard Practice for Accelerated Aging of Hot-Poured Asphalt Crack Sealant Using a Vacuum Oven*， 2024-05-19 Update
- AASHTO T 315 Standard Method of Test for Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR)*， 2025-05-16 Update
- AASHTO T 368 Standard Method of Test for Measuring Low-Temperature Flexural Creep Stiffness of Hot-Poured Asphalt Crack Sealant by Bending Beam Rheometer (BBR)*， 2024-05-19 Update
- AASHTO T 369 Evaluation of the Low-Temperature Tensile Property of Bituminous Sealants by Direct Tension Test.
- AASHTO T 370 Standard Method of Test for Measuring Adhesion of Hot-Poured Asphalt Crack Sealant Using Direct Adhesion Tester*， 2024-05-19 Update
- IEC 60584-1:2013 Thermocouples - Part 1: Ed. 3.0: EMF specifications and tolerances
AASHTO T 404-2023 history
- 2023 AASHTO T 404-2023 Evaluation of the Tracking Resistance of Hot-Poured Asphalt Crack Sealant by Dynamic Shear Rheomete (DSR)
