How much is the strength of the concrete test block in 7 days and 28 days?

1. The test block of standard maintenance is generally 80%.

2. If 60% of the concrete with fly ash is added. (It is possible that the standard intensity has just reached in 28 days).

Compressive strength of concrete.

It can reach more than 75% of the compressive strength in 28 days, different proportions are different, and there are more than 90% if you use a high-efficiency superplasticizer, you can convert it to about 80%.

1. The strength of concrete includes compressive strength and tensile strength.

Flexural strength, shear strength.

and the grip strength of concrete and steel bars.

2. Among them, the compressive strength of concrete is the largest, and the tensile strength is the smallest.

3. The compressive strength of concrete refers to the maximum pressure that the standard specimen can withstand per unit area under pressure until it fails.

4. Even under standard breeding conditions, due to the different varieties of cement and the influence of admixtures, this coefficient is different.

There is no specific basis for this, normally speaking, concrete 28 days to reach the design value can be considered qualified, if the concrete is used in construction projects, the evaluation of concrete is qualified, is based on the evaluation and acceptance criteria of concrete to assess whether the strength of the concrete in the project is qualified, the evaluation method sees: GB T50107-2010 concrete strength inspection and evaluation standards.

Generally speaking, the 7-day strength of concrete can reach about 70-80% of the 28-day strength of concrete in the standard state. Check out the original post".

The strength of concrete can basically reach about 50% of the design value in 3 days, 70-80% in 7 days, and about 100% in 28 days, or even higher.

Concrete has the characteristics of abundant raw materials and simple production process, so that the amount of concrete is getting larger and larger, and concrete has the characteristics of high compressive strength, good durability and wide range of strength grades.

These characteristics make it widely used, not only in various civil engineering projects, but also in shipbuilding, machinery industry, marine development, geothermal engineering, etc., concrete is also an important material.

As long as the concrete test block is made and cured according to the specification, the strength can basically reach about 50% of the design value in 3 days, 70-80% in 7 days, and about 100% in 28 days, or even higher.

The curing time depends on the cement type, such as ordinary Portland cement concrete, not less than 7 days and nights. The latter is suitable for high-rise structures and large-area concrete structures that are not easy to be cured by sprinkling, and the perchloroethylene resin plastic solution is sprayed on the concrete surface with a spray gun.

Conservation purposes. After the concrete is poured, if the climate is hot and the air is dry, if the maintenance is not carried out in time, the moisture in the concrete will evaporate too quickly, forming a dehydration phenomenon, which will make the cement particles that have formed a gel body can not be fully hydrated, can not be converted into stable crystals, lack of sufficient cohesion, and will appear flake or powder on the surface of the concrete. In addition, when the concrete does not have sufficient strength, the premature evaporation of water will also produce large shrinkage deformation and dry shrinkage cracks.

Question: My cement pavement has been poured for 5 days, and there are still a few days left to pass heavy trucks.

Within 3 days, the strength of cement is growing rapidly. Generally, it can reach more than 75% of the maximum strength, and can be used basically. Within 3 to 7 days, the strength growth of cement slows down, and generally reaches more than 95% of the maximum strength, which can be used completely.

After 7 days, the cement strength increases more slowly, and by 28 days, the cement strength reaches its maximum. 14 days is a median value, and it will not increase after 28 days. Therefore, the national standard regards these few days as several basic time points to measure the strength of cement.

Question: Can I pass for 10 days?

Hope it can help you kiss it.

Question PC425 cement, thickness 20 cm, with 8 mm of steel bars in the middle.

Purely in terms of pressure, there should be no problem, but it is difficult to guarantee that it will not crack, and it will take at least 12 days to kiss.

There is a battlefield to ask questions, and I am afraid of being crushed by a cart.

Question: Is the temperature 10 not guaranteed now?

The standard strength of concrete refers to the strength of 28 days under standard curing conditions. In real life, often due to actual needs, 7 days of concrete standard curing test blocks are added for testing to estimate the strength of 28 days for reference. Generally speaking, the strength should reach more than 80% of the design strength in 7 days.

It is understood that there is no such thing as a 3-day intensity. In addition to meeting the design strength, that is, 100%, the 28-day strength should also meet the standards for the evaluation of concrete strength.

Generally speaking, as long as the concrete test block is made and cured according to the specification, the strength can basically reach about 50% of the design value in 3 days, 70-80% in 7 days, and about 100% in 28 days, or even higher.

The strength of concrete is determined according to the temperature, curing conditions, and time, and there is no standard strength concept of 3 days, 7 days, and 28 days. There is only a standard value for concrete, such as C25. There is also a difference in whether the concrete is self-mixed or ready-mixed pumped on site, and the initial setting time and slump all affect the strength of the concrete.

The standard curing is 28 days to carry out the strength assessment, the same condition curing to 600 degrees Celsius to carry out the strength assessment, impermeable concrete to 60 days. When the concept is clear, the problem is clear.

The 28-day strength of concrete is implemented immediately according to the evaluation standard, GB T50107-2010 new standard. Assessed and non-assessed. 3D is generally more than 30%, 7D60 is above, most of them are above 70, 28D If the strength of the monoblock reaches more than 115%, then all are qualified, if not enough, you can refer to the standard to participate in the assessment.

The strength of concrete is expressed by its compressive strength, and the commonly used leadless strength standard refers to the compressive strength macro value of concrete at 3 days, 7 days, 14 days and 28 days after the end of the curing period.

The specific strength value varies depending on the concrete mix ratio, aggregate type, cement variety, curing conditions and other factors. The following are some common concrete compressive strength value ranges:

3-day strength: generally 60-70% of the design strength of the concrete 7-day strength: generally 70-80% of the design strength of the concrete 14-day strength: generally 85% of the design strength of the concrete

28-day strength: generally 100% of the design strength of concrete, it should be noted that these strength values are only used as a reference, and the specific strength should be tested and evaluated according to the actual situation of concrete.

Hello, I have seen your question and am preparing the answer, please wait a moment Hello, under normal curing, the strength of concrete can reach 40% 50% of the design value in 3 days, 70%-80% in 7 days, 80% 90% in 14 days, about 100% in 28 days, or even higher. 3 days, 7 days, and 14 days are the reference intensity and cannot be used as the final evaluation basis, and 28 days are the standard intensity and cannot be used as the final evaluation basis.

Summary. Dear Glad to answer for you. Concrete strength refers to the degree of pressure that the concrete is subjected to, and is usually measured with a "standard cube", that is, a concrete test block with a size of 150mm 150mm 150mm.

The detection of concrete strength is generally carried out for 3 days, 7 days, 14 days and 28 days, etc., and the following is the standard strength value of concrete in these periods (in mpa): -3 days: generally tested on the 3rd day after the concrete is poured, the strength of the concrete is about 10-40mpa at this time; - 7 days:

On the 7th day after the concrete is poured, the strength of the concrete is about 20-50MPa; - 14 days: Tested on the 14th day after the concrete is poured, the strength of the concrete is about 30-60MPa at this time; - 28 days: Tested on the 28th day after the concrete is poured, the strength of the concrete at this time is about 40-90MPa.

Dear Glad to answer for you. Concrete strength refers to the degree of pressure on the concrete, which is usually measured by a "standard cube", that is, a concrete test block with a cavity size of 150mm 150mm 150mm. The test of concrete strength is generally carried out for 3 days, 7 days, 14 days and 28 days, etc., and the following is the standard strength value of concrete in these periods (in MPa):

3 days: Generally, the test is carried out on the 3rd day after the concrete is poured, and the strength of the concrete is about 10-40MPa at this time; - 7 days: Tested on the 7th day after the concrete is poured, the strength of the concrete at this time is about 20-50MPa; - 14 days:

Tested on the 14th day after the concrete is poured, the strength of the concrete at this time is about 30-60MPa; - 28 days: Tested on the 28th day after the concrete is poured, the strength of the concrete is about 40-90MPa at this time.

It should be noted that the detection value of concrete strength is related to many factors such as the pouring method of concrete concrete mixed date, concrete mix ratio, and the quality of materials.