How to evaluate the strength of concrete, how to evaluate the strength of concrete?

Concrete strength assessment (not covered in this question.)Inspection

Assessment, i.e. concrete strengthEligibility

Assessment). Concrete strength assessmentbasiswithMethod:

Basis: "Concrete Strength Inspection and Evaluation Standard" GB T50107-2010.

Methods: 1. Statistical method evaluation. 2. Non-statistical method assessment.

1. Evaluation of statistical methods. In the evaluation of statistical methods, it is divided into "standard deviation known scheme (sample size is 3 consecutive groups of specimens)" and "standard deviation unknown scheme (when the sample size is not less than 10 groups)".

When statistical methods are used for evaluation, they should be carried out as follows:

1. When the concrete is continuously produced, the production conditions can be consistent for a long period of time, and the same strength grade concrete.

When the strength variation performance remains stable, it should be evaluated in accordance with the provisions of this standard.

2. Other circumstances shall be assessed in accordance with the provisions of this standard.

The sample size of a test batch should be 3 consecutive sets of specimens, and the strength of the test batch should meet the following requirements at the same time.

Provisions: <>

2. Non-statistical method assessment. When the number of sample specimen groups used for evaluation is less than 10 groups, non-non-statistical methods should be used to evaluate the concrete strength.

Methods for assessing the strength of concrete:

1. Statistical methods with known variance: the formula specified in the "Concrete Strength Inspection and Evaluation Standard" GB T50107 2010 is used for evaluation.

The sample capacity of a test batch should be 3 consecutive sets of specimens, and its strength should meet the following requirements at the same time:

mƒcu≥ƒcu，k＋ （

cu，min≥ƒcu，k－ （

When the concrete strength grade is not higher than C20, its minimum strength value should meet the following requirements:

cu，min≥，k （

When the concrete strength grade is higher than C20, the minimum strength value should meet the following requirements:

cu，min≥，k （

2. Statistical method with unknown variance: the formula specified in the "Concrete Strength Inspection and Evaluation Standard" GB T50107 2010 is used for evaluation.

When the sample size is not less than 10 groups, its intensity should meet the following requirements at the same time:

mƒcu≥ƒcu，k＋λ1●sƒcu （

cu，min≥λ2●ƒcu，k （

When the calculated value of the strength standard difference of the test batch concrete is less than that of cu, it should be taken. 1. 2 According to the concrete strength inspection and evaluation standard GB T50107 2010 table selection.

3. Non-statistical methods: the formula specified in the "Concrete Strength Inspection and Evaluation Standards" GB T50107 2010 is used for evaluation.

When the sample size is less than 10 groups, its intensity should meet the following requirements at the same time:

mƒcu≥＋λ3●ƒcu，k （

cu，min≥λ4●ƒcu，k （

4 take. Concrete strength grade C60, 3, C60, 3.