What is the abbreviation of C K in concrete fck

According to the relevant standards, the strength of building materials is uniformly expressed by the symbol "f".

The standard value of the axial compressive strength of concrete is fck,"c"It means prism, and "k" means standard value. The compressive strength of the concrete cube is "fcu". Among them, "cu" means cube.

The standard value of the compressive strength of the cube is expressed as "fcu,k".

For example, when the concrete strength grade is C20, FCU, K=20N mm2 (MPa), that is, the standard value of the 28D compressive strength of the cube is 20MPa.

Pronunciation: tóng <>

Explanation] concrete.

In engineering design and construction, the word "concrete" is often abbreviated as "concrete". The creator of the word "concrete" is Professor Cai Fangyin, a famous structural scientist.

The creator of the word "concrete" is Professor Cai Fangyin, a famous structural scientist. The date of creation is 1953. At that time, the teaching technology was backward, there were no tape recorders or photocopiers, and students relied on taking notes in class.

"Concrete" is the most commonly used word in construction engineering, but there are too many strokes, and it is laborious and time-consuming to write. So Cai Fangyin, who was quick-witted, boldly replaced "concrete" with the word "artificial stone".

Because there are 30 strokes of the word "concrete", and only 10 strokes of the word "artificial stone", it can save 20 strokes and greatly speed up the speed of note-taking. Later, "artificial stone" was synthesized into "concrete". The shape will mean "synthetic stone, concrete is as hard as stone".

And it is promoted among college students.

In July 1955, in the book "Structural Engineering Terminology" approved and promulgated by the "Terminology Room" of the Compilation and Publication Committee of the Chinese Academy of Sciences, it was clearly recommended that the words "concrete" and "concrete" should be used together. Since then, "concrete" has been widely used in all kinds of construction engineering books.

c denotes the compressive strength of concrete.

k denotes standard.

Taken together, this is the meaning of the standard compressive strength of concrete.

fck – standard value of axial compressive strength of concrete.

FCU, K is a concrete cubeCompressive strengthIt is a 150 millimeter cube specimen, under standard curing conditions, after 28 days of curing, the overall distribution of compressive strength measured by standard test method has a compressive strength value of not less than 95% guarantee rate.

Standard deviation of concrete strength.

In fact, the full name of the standard deviation of concrete strength should be the standard deviation of concrete compressive strength, and the calculation of concrete strength can not be completely error-free, because the detection method always has errors, so the detection value is not its true value. The standard deviation, on the other hand, reflects the degree of dispersion of a set of several first calls.

One of the most commonly used and useful forms of quantification is an important indicator of the accuracy of the calculations.

Therefore, when calculating the strength of concrete, it is necessary to calculate the standard deviation of concrete strength, and if you want to calculate the standard deviation of concrete strength, you need to calculate the formula.

The standard value of the compressive strength of a concrete cube is expressed by fcu,k.

GB50010 "Code for Design of Concrete Structures" stipulates that the standard value of the compressive strength of the concrete cube refers to the standard specimen of the cube with a side length of 150mm made and cured according to the standard method, and the cubic with a 95% guarantee rate measured by the standard test method at the age of 28 days has a good reputation for compressive strength.

The standard value of the compressive strength of a concrete cube is expressed by fcu,k.

GB50010 "Code for Design of Concrete Structures" stipulates that the standard value of compressive strength of concrete cube refers to the cubic standard specimen with a side length of 150mm made and cured according to the standard method, and the compressive strength of the cube with a 95% guarantee rate measured by the standard test method at the age of 28 days.

For engineering terms, the English expression 'standard value' is generally used'characteristic value', such as characteristic strength, characteristic modulus of elasticity, and so on.

As for why K is used to represent C in FCK and FTK, it may be derived from German, because Kennwert in German = characteristic value in English, and then it has been used conventionally. 'c'There are too many things that can be represented, used'k'Representing 'standard' or 'characteristic' can be more explicit.

k-value: Stress distribution coefficient is indicated. k= max both.