GB/T 38140-2019 in English

Technical background and scope of application of the standard

This standard was jointly drafted by 28 institutions including China Building Materials Science Research Institute. It established a standardized accelerated test method for seawater erosion in response to the durability evaluation needs of cement-based materials in marine environments. It is applicable to the performance degradation evaluation of cement mortar specimens in simulated seawater environments.

Core test principle

The compressive strength retention rate (Rᵢ/R₀×100%) is used to quantitatively characterize the cement's anti-erosion ability. This index can comprehensively reflect the coupling effects of multiple factors such as chloride ion penetration and sulfate erosion.

Key test element control

1. Preparation of simulated seawater solution

According to the requirements of Appendix A of the standard, the solution must contain 7 kinds of salts, the main components are:

• Sodium chloride 122.7g/L (main salt in simulated seawater)
• Sodium sulfate 20.5g/L (induces sulfate corrosion)
• Magnesium chloride 25.6g/L (aggravates magnesium ion corrosion)

The pH value is strictly controlled at 8.2±0.2, and a pH meter is used for regular testing.

2. Dry-wet cycle process parameters

Implementation points and common problems

Handling of special situations

When natural seawater is used, the following shall be noted in the report:

• Sampling location and time
• Main ion concentration test results
• Filtration treatment method

Analysis of standard technology evolution

Compared with the JC/T1086-2008 chloride ion diffusion coefficient test method, this standard has the following innovations:

1. Introducing multi-ion coupling corrosion to simulate a more realistic marine environment
2. Using dry-wet cycle acceleration mechanism to shorten the test cycle
3. Establishing strength retention rate as a quantitative evaluation indicator

In the future, electrochemical test methods may be added to achieve real-time monitoring of the corrosion process.