Standard specimen dimensions for the flexural strength of concrete

The flexural strength test uses 150mm, 150mm 600mm (or 550mm) trabecular as standard specimens.

Due to the direct influence of the repeated action of vehicle load and environmental factors (such as temperature and humidity), cement concrete pavement requires high flexural strength, durability, wear resistance and slip resistance to concrete slab. Among them, flexural strength is an important control index of concrete pavement, and whether its size meets the design requirements will directly affect the overall quality and service life of the pavement.

Meeting these requirements depends largely on the quality of the raw materials, the composition of the mixture, and the construction control on site. Therefore, in the engineering concrete road requirements, analyze the factors that affect its strength, so as to select qualified materials, scientific design, reasonable construction, to meet the requirements of the indicators of cement concrete pavement.

The failure of cement will directly affect the strength of concrete and the properties of its mixture. This mainly depends on the technical properties of the cement itself, such as calcification rate, shrinkage cracking, abrasion performance, etc., therefore, the cement for pavement requires high flexural strength, shrinkage, wear resistance, good durability and low elastic modulus and other technical properties.

GB T 50081-2002 Standard for Test Methods for Mechanical Properties of Ordinary Concrete stipulates: 150 150 600mm (or 550) prismatic mold test, or 100 100 400mm

Cement flexural standard size: 40mmx40mmx160mm; Concrete flexural standard size: 150mmx150mmx600mm or 150mmx150mmx550mm.

Selection of cement varieties and labels. Generally, cement with high strength, small dry shrinkage, good wear resistance and durability should be used. The selection of its varieties and labels must be based on the grade of the road.

Factors such as construction period, paving time, method and economy are comprehensively considered. Cement marking is usually recommended.

Extra-heavy and heavy traffic is not less than others.

Effect of raw material quality on flexural strength of cement concrete pavement:

1.The failure of cement will directly affect the strength of concrete and the properties of its mixture. This mainly depends on the technical properties of the cement itself, such as calcification rate, shrinkage cracking, abrasion performance, etc., therefore, pavement cement requires high flexural strength, shrinkage, wear resistance and laughter, good durability and elastic modulus.

Inferior technical nature.

2.Effect of cement dosage on concrete strength. The dosage is too small to meet the requirements of concrete strength, durability and wear resistance; The dosage is too large, although it can meet the strength requirements, but the hydration heat rise in the concrete is large, and the shrinkage is also large, which is easy to crack due to shrinkage.

Therefore, the amount of cement should meet the minimum cement consumption requirements, but the maximum cement consumption should also be controlled.

Standard size of cement anti-simple digging banquet folding: 40mmx40mmx160mm;

Standard size of concrete bending resistance: 150mmx150mmx600mm or 150mmx150mmx550mm.

The compressive strength of the concrete specimen MPa = the load of the specimen (n) and the bearing area of the specimen (mm2).

Concrete cube specimen specifications 150*150*150mm and 100*100*100mm":

Its value is: for 200mm 200mm 200mm specimen;

For 100mm 100mm 100mm specimens.

When the concrete strength grade is C60, it is advisable to use the standard specimen 150mm 150mm 150mm specimen. The conversion factor of 150mm 150mm 150mm specimen is.

The flexural strength of concrete is calculated using the formula f fi bh.

Where: f--ultimate load (n);

l--distance between bearings, l 450mm;

b--Specimen width (mm);

h--Specimen height (mm).

The influence of construction factors on the flexural strength of cement concrete pavement is eliminated.

1) The influence of mixing conditions on the strength of concrete.

It mainly includes mixing equipment, mixing environment, mixing process, etc. The quality of the mixed concrete is also different due to the different equipment, environment and process. In particular, the mixing time and temperature have a great influence on the strength of concrete.

Therefore, the quality of concrete should be stable, the strength should be guaranteed, the mixing conditions must be improved, the mixing time must be strictly controlled, and the mixing should be uniform.

2) The influence of transportation conditions on the strength of concrete.

The transportation time should not be too long, so as to avoid premature condensation and hardening of concrete, which will affect the construction. Generally, it can be determined according to the initial setting time of cement and the construction climate.

3) In the pouring of concrete, whether the vibration is sufficient also directly affects the formation of concrete strength.

Therefore, after concrete paving, it should be vibrated in time and strive to be sufficient. In order to improve the vibration effect, plug-in and plate vibrators can be used to work together to improve the compactness and strength of concrete.

The flexural strength of concrete is calculated using the formula f fi bh. A set of three specimens.

The calculation and determination of the flexural strength test results are carried out according to the following methods:

1 If the fracture position of the lower edge of the specimen is between two lines of action of concentrated load, the flexural strength f (MPa) of the specimen is calculated as follows:

2. The determination of the flexural strength value shall comply with the following provisions:

1) should take the arithmetic mean value of 3 specimens as the flexural strength value of this group of specimens, should be refined to;

2) When the difference between one of the maximum or minimum values and the intermediate value of the three measured values exceeds 15% of the intermediate value, the maximum value and the minimum value should be rounded together, and the intermediate value should be taken as the flexural strength value of the group of specimens;

3) When the difference between the maximum and minimum values and the median value is more than 15% of the median value, the test results of this group of specimens are invalid.

3 When one of the three specimens is located outside the two concentrated loads, the concrete flexural strength value should be calculated according to the test results of the other two specimens. When the difference between these two measured values is not greater than 15% of the smaller value of these two measured values, the flexural strength value of the group of specimens should be calculated according to the average value of these two measured values, otherwise the test of the group of specimens is invalid. When the fracture position of the lower edge of two specimens is outside the two concentrated load lines, the test of this group of specimens is invalid.

4. When the size of the specimen is 100mm 100mm 4 00mm non-standard specimen, it should be multiplied by the size conversion factor; When the concrete strength grade is not less than C60, it is advisable to use standard specimens; When non-standard specimens are used, the size conversion factor should be determined by the test.

The pressed data can be divided directly.

1. After the specimen is taken out from the maintenance site, the test should be carried out in time, and the surface of the specimen and the upper and lower bearing plate surfaces should be wiped clean.

2. Place the specimen on the lower pressure plate or backing plate of the testing machine, and the bearing surface of the specimen should be perpendicular to the top surface when forming. The center of the specimen should be aligned with the center of the lower pressure plate of the testing machine, and the upper pressure plate should be adjusted when the upper pressure plate is close to the test piece or the steel backing plate, so that the contact is balanced.

3. In the process of the test, the load should be continuously and uniformly, and the concrete strength grade (C30, the loading speed should be taken per second; Concrete strength grade" C30 and (C60, take every second.

Concrete strength grade》 C60, take every second

4. When the specimen is close to failure and begins to deform sharply, the throttle of the testing machine should be stopped and adjusted until it fails, and then the failure load should be recorded. (5) Cube compressive strength.

The calculation and determination of the test results are carried out according to the following methods: (1) Concrete cube.

The compressive strength should be calculated as follows:

fcc=f/a

where: FCC: compressive strength of concrete cube specimen (MPa); f: Failure load of the specimen (n);

A: Bearing area of the specimen (mm).

The calculation of the compressive strength of the concrete cube should be accurate to the determination of the strength value should comply with the following provisions: The arithmetic mean of the three test measurements.

As the intensity value of the group of specimens (.

If the difference between the maximum value or the minimum value and the intermediate value of one of the three measured values exceeds 15% of the intermediate value, the maximum and minimum values should be carefully divided by the basic mode, and the intermediate value should be taken as the compressive strength value of the group of specimens.

If the difference between the two and the median value of the maximum or minimum value of the three measured values is more than 15% of the median value, the test data is invalid.

Concrete strength grade (C60, the strength values measured with non-standard specimens should be multiplied by the size conversion factor, and its values are correct.

The specimen of 200mm x200mmx200mm is; Right.

The 100mmx100mmx100mm specimen is.

When the concrete strength grade is 3C60, it is advisable to use standard specimens; When using non-standard specimens, the size conversion factor should be determined by the test.

Summary. The size of cement concrete flexural tensile strength specimens is usually determined according to relevant standards, such as national standards, industry standards or project specifications, etc., the following are some common cement concrete flexural tensile strength specimen sizes: Standard beam specimen size:

Length: Generally 1000mm, but it can also be adjusted as needed. Width:

It is generally 100mm, but it can also be adjusted according to your needs. Height: Generally 100mm, but it can also be adjusted as needed.

Reduced beam specimen size: length: generally 500mm, but can also be adjusted as needed.

Width: Generally 50mm, but it can also be adjusted as needed. Height:

It is generally 50mm, but it can also be adjusted according to needs. It should be noted that the selection of the size of the specimen should meet the requirements of the relevant standards, and take into account the use in the actual project, the conditions of the test equipment and the purpose of the test. When carrying out the flexural tensile strength test of cement concrete, the preparation, maintenance and test operation of the specimen should be carried out in accordance with the standard requirements to ensure the accuracy and reliability of the test results.

I'm still a little confused, can you be more detailed?

The size of cement concrete flexural tensile strength specimens is usually determined according to relevant standards, such as national standards, industry standards or project specifications, etc., the following are some common cement concrete flexural tensile strength specimen sizes: Standard beam specimen size: length:

It is generally 1000mm, but it can also be skillfully adjusted according to the needs of filial piety. Width: Generally 100mm, but it can also be adjusted as needed.

Height: Generally 100mm, but it can also be adjusted as needed. Reduced Beam Specimen Size:

Length: Generally 500mm, but it can also be adjusted according to your needs. Width:

It is generally 50mm, but it can also be adjusted according to needs. Height: Generally 50mm, but it can also be adjusted according to your needs.

It should be noted that the selection of the old solution of the specimen size should meet the requirements of the relevant standards, and take into account the use in the actual project, the conditions of the test equipment and the purpose of the test. When carrying out the flexural tensile strength test of cement concrete, the preparation, maintenance and test operation of the specimen should be carried out in accordance with the standard requirements to ensure the accuracy and reliability of the test results.