The problem of the standard value of the compressive resistance of the C30 concrete test block

The pressure value displayed with the press, divided by the compression area.

The pressure is converted to Newtons, and the area is in square millimeters, and the resulting unit is megapascals.

Strictly speaking, the compression area should be the product of the edge lengths of the real test block. However, because the error is small, the standard number is generally used.

For example, if a cube with a side length of 150 mm is 800 kN under a failure load on a press, then the area is 22,500 mm² and 800,000 Newtons under pressure. The compressive strength is 800,000 Newtons 22,500 square millimeters = megapascals.

After skillful use, it can be like this: 800

The standard value of compressive resistance is the test block corresponding to 150.

There is no standard compressive standard value for non-standard test blocks.

Of course, this is a conceptual problem.

If it has to say, it probably means a correction for the 100mm test block.

30 Because the coefficient of multiplication of the 100mm test block in the strength evaluation, because the compressive strength of the small test block is large.

30mp.Tell you what is the standard value of compressive strength, and you will naturally understand.

The standard value of the compressive strength of the concrete cube refers to the compressive strength with a 95% guarantee rate measured by the standard test method at the age of 28 days with the standard test method of the cube specimen with a side length of 150mm made and cured according to the standard method. The concrete strength grade is divided according to the standard strength of the cube compressive strength, and the concrete strength grade is expressed by the symbol C and the standard value of the cubic compressive strength (in MPa).

The concrete strength grade should be expressed in the first letter of the English name of the concrete plus its strength standard value. Such as C20, C30, etc.

"Concrete Strength Inspection and Evaluation Standard" GB T50107-2010

The values of the compressive range of C20 C25 C30 in concrete are: C20, C25, C30. The compression area of the 150mm*150mm*150mm test block is 150mm*150mm = 2500 mm.

Ultimate load kn compressive area 22500 mm = compressive strength, c25, c30.

Concrete:

Ordinary concrete refers to the artificial stone made of cement as the main cementitious material, mixed with water, sand and gravel, mixed with chemical admixtures and mineral admixtures if necessary, matched in appropriate proportions, and hardened by uniform mixing, dense molding and curing. Concrete is mainly divided into two stages and states: the plastic state before setting and hardening, that is, fresh concrete or concrete mixture; The hard state after hardening, i.e., hardened concrete or concrete.

Concrete strength grades are divided by the standard value of the compressive strength of the cube.

The compression area of the 150mm*150mm*150mm test block is 150mm*150mm = 2500 mm.

Ultimate load kn Compressive area 22500 mm = compressive strength mpa

c20≥c25≥

C30 Good luck!

Concrete strength calculation method: compressive strength (MPa) = ultimate load (n) compression area (mm 2).

100mm : Concrete strength size conversion factor.

150mm: Size conversion factor.

200mm: Size conversion factor.

Note: (1) "Vehicle" refers to motor vehicles and non-motor vehicles.

2) "Motor vehicle" refers to a wheeled vehicle that is driven or towed by a power unit and driven on the road for personnel or for transporting goods and carrying out special engineering operations.

3) "Non-motorized vehicles" refers to vehicles driven by human or animal power and driven on the road, as well as motorized wheelchairs for the disabled, electric bicycles and other vehicles that are driven by power units but have a design maximum speed, empty mass and external dimensions that meet the relevant national standards.

The compressive strength of the C30 concrete test block must reach at least 30MPa (100%) to be qualified, or now it must be reached according to non-mathematical statistics to be qualified.

For example, the load values of a single block extruded from a set of 100*100*100mmC30 test blocks are respectively (kn).

Equivalent to the compressive strength of the concrete cube of the standard specimen = [(431+420+413)*1000 3] (100*100)*

To reach the design strength (C30) of 40 30 * 100% = 133%, this group of test blocks to meet the requirements of the design strength level C30.

Meet the non-statistical evaluation requirements of the "Concrete Strength Inspection and Evaluation Standard" (GB T50107-2010). The concrete strength test result reached 136% of the design strength, and the test block was nuclear-resistant.

The compressive strength with a 95% guaranteed rate was measured by the standard test method at 28 days of age.

The concrete strength grade should be determined according to the standard value of the compressive strength of the cube.

The standard value of cubic compressive strength refers to the cube specimen with a side length of 150mm that is sensitized or cured according to the standard method.

Code for Design of Concrete Structures stipulates that the standard value of C30 concrete compressive strength is, the design value is the standard value of concrete compressive strength, and the design value is.

Meet the non-statistical evaluation requirements of the "Concrete Strength Inspection and Evaluation Standard" (GB T50107-2010). The concrete strength test result reaches 136% of the design strength, and the test block is qualified.

The test compressive strength value of C30 concrete test block is 30MPa.

In accordance with the "Standard for Test Methods for Mechanical Properties of Ordinary Concrete" GB T50081-2002, the cube with a side length of 150mm is cured to 28 days old under the conditions of standard curing (temperature 20 2, relative humidity above 95%), and the Huner ultimate compressive strength measured by the standard test method is called the compressive strength of the concrete standard cube, which is represented by FCU and K.

For example, a concrete with a strength class of C30 is 30MPa without FCU, and the K< is 35MPa.

The axial compressive strength design value of C30 is and the axial compressive strength design value of C40 is. The standard value of axial compressive strength of C30 is and the standard value of axial compressive strength of C40 is.

Ordinary concrete is divided into c fifteen strength grades. Concrete cube compressive strength: In accordance with the provisions of the national standard "Standard for Test Methods for Mechanical Properties of Ordinary Concrete" (GB T 50081-2002), the compressive strength value measured by the compressive strength test measured by the compressive strength test of a cube specimen with a side length of 150mm under standard curing conditions (temperature 20+-2 degrees, relative humidity greater than 95%) for 28 days is called the cubic compressive strength of concrete.

Concrete test blocks are divided into two types: standard culture and the same conditions. Generally, there is no problem when the intensity reaches about 70 80 in 7 days, and the design strength should be reached in 28 days.

If the quality inspection station is sent for inspection, it is different, taking the C30 test block as an example, the average strength of the test block in 30 days is 30, and the minimum strength of the test block must be greater than 30 and the quality inspection station will be qualified if the above two conditions are met at the same time.

There is no standard answer to this question, and different ratios and cements should be regressed with sufficient data to obtain the approximate strength value of the non-standard age. Generally, the 3-day strength of the specimen of the same specification can reach 50% 60% for 28 days, 75% 80% for 7 days, the average strength of 28 days is not lower than the design strength, the minimum can not be less than 85%, and the average strength can not be greater than 150% (for reinforced concrete).

First of all, the concrete strength grade is C15 C80, there is no C10 level, the following number represents the pressure value, for example, C15 is greater than or equal to 15MPa and less than 20MPa, 3 days to reach 70% of the design value, 7 days to reach 100%, 28 days is stable 100% and above value.

This is also the method of determining the strength grade of concrete. If a non-standard test block is used, e.g. 100 100 10mp m2 with a side length of 5 N/mm², the standard value is per mm².