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Interpretation of the New Cement Mortar Strength Testing Standard GB/T 17671-2021

 

1. Background

Cement strength is the core indicator of cement quality and a fundamental guarantee of structural safety in construction projects. The updated GB/T 17671-2021 “Method of Testing Cements – Determination of Strength (ISO Method)” officially came into effect on July 1, 2022, replacing the 1999 edition.

This revision systematically improves testing equipment requirements, operational procedures, and data processing methods, making China’s cement strength testing more scientific and closely aligned with ISO international standards.

2. Key Changes in the New Standard

1. Stricter Equipment Requirements

  • Higher precision requirements for mortar mixers, jolting apparatus, and compression testing machines

  • Enhanced requirements for structural rigidity and stability

  • Mandatory calibration and performance verification

2. More Standardized Procedures

  • Clear specifications for mixing water quality

  • Standardized cement mixing procedures

  • Detailed specimen molding and surface leveling requirements

  • Mandatory covering during curing to reduce moisture evaporation errors

3. More Scientific Data Processing

  • New provisions for handling abnormal flexural strength values

  • Optimized strength calculation methods

  • Reduced impact of random errors on final evaluation results

3. Impact on Laboratories and Technicians

1. Equipment Upgrading Becomes Essential

Laboratories must inspect and upgrade their equipment according to the new standard, especially ensuring that compression testing machines meet updated precision and rigidity requirements.

2. More Refined Operational Management

From sample preparation and water quality control to specimen molding and curing, every step directly affects strength results. Technicians must receive systematic training and strictly follow standard operating procedures.

3. More Accurate and Reliable Results

With standardized outlier handling and improved calculation methods, test results are more objective and better reflect actual engineering performance.

4. Conclusion

The revision of GB/T 17671-2021 marks an important step toward higher-quality and internationally aligned cement standards in China.

By raising equipment standards, refining procedures, and standardizing data management, the new regulation significantly improves the accuracy and repeatability of cement mortar strength testing, providing stronger technical support for construction quality and safety.

Laboratories and enterprises should complete the transition as soon as possible to ensure compliance and maintain competitiveness.

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