AASHTO T 158M/T 158-2023
Bleeding of Concrete
- Standard No.
- AASHTO T 158M/T 158-2023
- Release Date
- 2023
- Published By
- American Association of State Highway and Transportation Officials US / AASHTO
- Latest
- AASHTO T 158M/T 158-2023
- Introduction
Standard Overview and Technical Background
Concrete Bleeding Test StandardAASHTO T158M/T158-23 is the latest version released by the American Association of State Highway and Transportation Officials in 2023. The standard has undergone important technical revisions. Bleeding refers to the phenomenon that mixed water in fresh concrete migrates upward under the action of gravity and accumulates on the surface. This characteristic directly affects the durability, surface quality and overall performance of concrete.
Scope of application and core requirements of the standard
This standard specifies two test methods for determining the relative bleeding amount of mixed water in fresh concrete samples. The main difference lies in the degree of vibration to which the concrete samples are subjected. The standard clearly requires: When comparing different concretes, all tests should be carried out using the same method, and the difference in sample mass should not exceed 1kg.
Test dimensions Method A (tamping method) Method B (vibration method) Applicable scenarios Vibration level Light tamping Sufficient vibration Simulation of different construction conditions Simulated working conditions Non-intermittent vibration conditions Sufficient vibration conditions Select according to actual construction conditions Accuracy Requirements Standard Deviation 0.71-1.77% Deleted Quality Control Basis Sample Mass ≤1kg Difference Same as Left Ensure Comparability Test Equipment and Technical Requirements
Core Test Device
The standard specifies precise equipment specifications: a cylindrical container with a capacity of approximately 14L, an inner diameter of 255±5mm, and a height of 280±5mm. The inner surface should be smooth and corrosion-free. The container must be equipped with a lid to prevent evaporation and ensure the accuracy of the test results.
Measurement Instrument Requirements
Balance should have sufficient capacity and an accuracy of 0.5%; Pipette should be used to aspirate free surface water; 100mL graduated cylinder should be used to collect and measure exudate; Tamping Rod should be a round, straight steel rod with a diameter of 16±2mm and a length at least 100mm greater than the measuring depth.
Test Procedure and Operating Specifications
Sample Preparation
Laboratory concrete preparation should be conducted in accordance with R39M/R39, while field sampling should be conducted in accordance with R60M/R60. The container should be filled to a height of 255±3mm, and surface finishing should not exceed three passes with a trowel.
Test Environment Control
Under laboratory conditions, the temperature and humidity of all mixing rooms, curing rooms, water tanks, equipment, and raw materials should be maintained in accordance with M201, using thermometers that meet the requirements of M339M/M339.
Bleeding Water Collection Procedure
Bleeding water should be collected every 10 minutes for the first 40 minutes, and every 30 minutes thereafter until bleeding ceases. To facilitate collection, place a 50mm thick block on one side of the container to tilt the specimen 2 minutes before each water collection. After water collection, return the specimen to a horizontal position to prevent vibration.
Calculation Method and Data Processing
Bleeding Water Calculation Formula
Cumulative bleeding water is calculated as a percentage of net mixing water: C = (w/M) × S; Bleeding Rate = D/C × 100. Where C is the mass of water in the sample (g), M is the total mass of the batch (kg), w is the net mixing water (kg), S is the sample mass (g), and D is the mass of bleeding water (g).
Data Presentation
To compare bleeding rates, a graph of cumulative bleeding volume versus elapsed time can be plotted to visually demonstrate the differences in bleeding characteristics between different concretes.
Precision Control and Quality Assurance
Precision Indicators
Single Operator-Day-Multiple Batch Standard Deviation (1s): 0.71% for bleeding rates between 0-10%, 1.06% for 10-20%, and 1.77% for >20%. The deviation between the results of two correctly tested batches of the same mix ratio, performed by the same operator on the same day, should not exceed: 2.0% for 0-10%, 3.0% for 10-20%, and 5.0% for >20%.
Description of deviation
The test method has no deviation because the determined value can only be defined based on the test method. This statement reflects the confidence of the standard setters in the reliability of the method.
Analysis of technical evolution of standards
The important change in the 2023 version is the deletion of Method B using a vibration platform, and only retaining Method A of the tamping method. This revision reflects that the tamping method is more representative in actual engineering applications, while simplifying the test procedures. The standard number is changed to a dual unit system, which is consistent with Section 1.3, reflecting the internationalization trend.
Comparison of historical versions
Version year Main changes Technical basis Scope of impact 2023 version Delete Method B, unified as the tamping method Representativeness of actual projects Simplified operational procedures Early version Includes methods A and B Comprehensive coverage of different working conditions High operational complexity Unit system Unification of the two unit systems International requirements Improved applicability of the standard Implementation Recommendations and Engineering Applications
Key Points for Laboratory Implementation
Establish a complete quality management system that complies with R18 requirements; regularly calibrate equipment, especially balances and thermometers; and strictly control test environment conditions to ensure comparability of results.
Field Application Guidance
Select representative samples to avoid segregation; conduct tests promptly to prevent changes in concrete properties; and record mix proportions and material information in detail to facilitate result analysis.
Result Interpretation and Engineering Significance
Excessively high bleeding rates may lead to reduced surface strength and sanding; excessively low bleeding rates may affect workability. The appropriate bleeding rate range should be determined based on project requirements and environmental conditions.
Standard Correlations and System Integration
The T158 standard is interlinked with several AASHTO and ASTM standards: M201 (Environmental Control), M339M/M339 (Thermometers), R18 (Quality Management), R39M/R39 (Specimen Preparation), R60M/R60 (Sampling), and T121M/T121 (Density Determination), forming a comprehensive system of concrete performance testing standards.
Synergistic Application of Standards
In actual projects, T158 should be used in conjunction with other relevant standards to form a systematic concrete quality control plan. In particular, coordination with standards for mix design, sampling, mixing, and curing ensures representative and reliable test results.
Technology Development Trends and Outlook
With the development of concrete material technology, especially the application of high-performance concrete and self-compacting concrete, water seepage test methods may need to be further optimized. Possible future development directions include: the application of automated testing equipment, the integration of real-time monitoring technology, and the combination with digital twin technology.
Standard-setting organizations should continue to pay attention to the development of new materials and new processes, and revise test methods in a timely manner to ensure the advancement and applicability of standards. At the same time, they should strengthen international standard coordination and promote technical exchange and cooperation.
AASHTO T 158M/T 158-2023 Referenced Document
- AASHTO M 201 Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of Hydraulic Cements and Concretes
- AASHTO M 339M/M 339 Thermometers Used in the Testing of Construction Materials
- AASHTO R 18 Standard Practice for Establishing and Implementing a Quality Management System for Construction Materials Testing Laboratories
- AASHTO R 39M/R 39 Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory
- AASHTO R 60M/R 60 Sampling Freshly Mixed Concrete
- AASHTO T 121M/T 121 Standard Method of Test for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete*， 2024-01-01 Update
- AASHTO T 19M/T 19 Standard Method of Test for Bulk Density (\"Unit Weight\") and Voids in Aggregate*， 2025-10-03 Update
AASHTO T 158M/T 158-2023 history
- 2023 AASHTO T 158M/T 158-2023 Bleeding of Concrete
