There are several confusions about the strength assessment of concrete

For the same number, you can be assessed together for what you poured on the same day.

If it is not poured on the same day, it means that the production conditions may change, so they cannot be evaluated together.

You can take a look at the "National Standard of the People's Republic of China for Concrete Strength Inspection and Evaluation Standards".

gb50107－2010

There will be no confusion.

It can be evaluated together, and this evaluation is to look at the strength guarantee rate of C35.

You can't evaluate them together, they must be assessed separately, although the intensity is the same, but because their strength levels are different, so they must be separated Ha I wish you all the best in your work.

Theoretically, no, there are regulations in the standards.

However, you can go to the engineering quality inspection station and ask them, they are the ones who will make the final decision on whether you can submit your information or not.

It's best to ask all the information when you do it, because Chinese rules have a lot to do with people.

And also. I have an excel formula for strength rating, if you need to ask me to get it.

My understanding: before December 1 this year, it will be assessed according to GBJ107-87. The foundation division can be assessed together with a grade of concrete.

Because the strip foundation, the single foundation, the ground ring beam (the pouring time of C35 and the raw materials used are basically the same), the C15 cushion is assessed separately.

GBJ107-87 Concrete strength should be inspected and assessed in batches, and an acceptance batch should be assessed.

The concrete should be made of the same strength grade, the same age, as well as the production process conditions and fit.

Cast-in-place concrete on the construction site should be more than essentially the same as the composition of the concrete.

The acceptance project of the project is divided into acceptance batches, and each acceptance project shall be in accordance with the current national standards.

The quality inspection and evaluation standards for construction and installation projects are determined.

The single foundation (C35) and the geosphere beam (C35) should be able to be assessed together, and both belong to the concrete structure subdivision project in the foundation and foundation division. It seems that statistical methods are easier to pass than non-statistical methods.

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 companionship method evaluation.

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

When using the statistical method of selling well, it should be carried out according to the following provisions:

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.

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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.

Strength assessment of concrete typically involves a variety of tests and methods, the most common of which is to perform a compressive strength (compressive strength) test. Here are some commonly used ways to assess the strength of concrete:

Compressive strength test (compressive strength test): This is the most common method of assessing the strength of concrete. During the test, a small sample is taken from a concrete sample and then compressed and loaded in standard test equipment.

Results are expressed in units of area per square (MPa or psi). The compressive strength of concrete is usually tested at 28 days of age, which is one of the important parameters of concrete strength.

Tensile strength test (tensile strength test): This test method measures the strength of concrete in a tensile state. However, the tensile strength of concrete is usually low, so it is rarely used in practical simple works.

Flexural Strength Test (Flexural Strength Deficit Test): The flexural strength of concrete is assessed by applying a bending force to a concrete sample. This is useful when you need to consider the performance of concrete in beams, slabs, etc.

Freeze-thaw cycle test: This test simulates the performance of concrete in cold climates, and evaluates the durability and strength loss of concrete through multiple freeze-thaw cycles.

Ultrasonic testing: Ultrasonic testing can measure the speed of sound wave propagation in concrete, which can infer the density and strength of concrete.

When the statistical method is in line with the evaluation method, the strength of the concrete test block is less than 85% of the design strength is unqualified; When Yingzhao meets the evaluation of the non-unified potato metering method, the strength of the concrete test block is less than 90% of the design strength is unqualified. Regardless of any method of evaluation, the strength of the concrete test block is less than 85% of the design strength is unqualified.

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.