Concrete Strength Evaluation: GB/T 50107 Online Calculation
What is Concrete Strength Evaluation?
Concrete strength is evaluated from the compressive strength of standard-cured 150 mm cube specimens: cubes of the same strength grade, mix and process form an acceptance batch, which is judged by statistical or non-statistical methods. GB/T 50107 selects the method by the number of cube groups — such as three consecutive groups or ten or more — and the conclusion drives project acceptance and quality traceability for the concrete work.
When to Use It
Use it for acceptance of concrete works per GB/T 50107, for batch evaluation from ten or more cube groups by the statistical method with unknown standard deviation, or with known standard deviation when the same concrete variety has an established σ and group requirements are met, and for fewer than ten groups by the non-statistical method. It also handles non-standard cubes through the conversion factors (100 mm × 0.95, 200 mm × 1.05).
How to Use It (Step by Step)
Enter each cube's compressive strength, the strength grade, and the known standard deviation if available; the tool identifies the group count and method, computes the mean and standard deviation, compares the acceptance statistics against the criteria, and outputs the verdict with an AI interpretation. Cube representative values must follow the standard's middle-value rule and out-of-range handling, and failed batches are re-verified by rebound or core drilling per the standard.
Key Formulas / Example
Statistical method with unknown σ (n ≥ 10): mfcu ≥ fcu,k + λ1·s and fcu,min ≥ λ2·fcu,k, with λ1 and λ2 from the table by number of groups; the known-σ method applies its own criteria from the standard. Non-statistical method (fewer than 10 groups): mfcu ≥ λ3·fcu,k and fcu,min ≥ λ4·fcu,k, where λ3 = 1.15 and λ4 = 0.95, grade-dependent. The non-statistical method is more conservative.