How many days does it generally take to maintain under the same conditions

When the normal maintenance needs to be 28 days, and the average daily temperature exceeds 600 degrees day by day, the test block compression test should be carried out, and the lower 0 degrees can not be counted, but the normal cumulative date will be between 14 and 60 days.

If it is still less than 600 degrees after 60 days in winter, it means that the maintenance conditions are poor, and the maintenance time needs to be increased, so that it can reach the standard of 600 degrees, and do not be limited by the number of days.

Why do you want to cure concrete?

1. After the concrete steel is poured, it must go through the process of maintenance, and this step will take a long time, because it is related to the quality of the concrete.

2. The actual curing must refer to the current temperature and humidity, if the natural conditions are not up to standard, it needs to be artificially cured to ensure that the temperature and humidity are appropriate, so as to ensure that the strength of the concrete can be improved normally.

3. In addition, curing can also avoid the problem of cracking in the outer layer of concrete, such as watering, which will normally start within 8 to 12 hours after pouring, and you can also use the rest of the curing methods, such as covering and insulation, which takes about 7 days.

There is the same condition test block that is left in place when the cantilever member is removed, generally about seven days, and there is the age corresponding to the equivalent maintenance age when the daily average temperature accumulates to 600 day by day, and the age of 0 and below is not counted; The equivalent maintenance period should not be less than 14 days and should not be greater than 60 days; 1. The structural components or structural parts corresponding to the maintenance specimens under the same conditions shall be jointly selected by the supervision (construction), construction and other parties;

2. For the concrete strength grade in the concrete structure project, the same condition maintenance specimen is retained.

3. The number of curing specimens under the same conditions of the same strength grade shall be determined according to the quantity and importance of concrete engineering, and shall not be less than 10 groups and not less than 3 groups.

Unlike conditional and standard maintenance, it is not defined by the number of days! The standard curing is 28 days, while the same condition curing is the cumulative daily temperature of 600 degrees Celsius!

You can have as many days as you want.

28 days. When the daily average temperature reaches 600 ·d day by day, the compressive strength of the concrete test block should be tested, and the age of 0 and below is not counted. The age should not be less than 14 days and should not be more than 60 days.

However, in practice, there may be problems such as how to operate in winter even if it is 60 days, but less than 600 degrees. If the above principle is true, it should be understood that the maintenance conditions obtained are insufficient, and the maintenance time should be continued to be extended so that the maintenance conditions can be obtained at 600 degree days, that is, it is not necessary to be completely limited to the number of days. At the same time, if it is steamed, it is not necessary to insist that it must reach 14 days, because the high temperature has accelerated the hydration reaction of the cement.

Winter construction of the same condition test block.

The temperature is 0 for most of the winter construction, so that the 600 ·d test block under the same conditions does not meet the needs of construction testing. Under the same conditions, 28 days were transferred to the standard culture test block.

It is also known as the same condition test block of negative temperature to positive temperature.

During winter construction, after 28 days of maintenance under the same conditions, the test block will be transferred to the standard maintenance box for 28 days.

Under the same conditions, the test block was transferred to room temperature for 28 days.

It is also known as the test block with the same conditions from negative temperature to normal temperature.

During winter construction, the test block is maintained under the same conditions until the end of winter, and the same conditions are maintained for 28 days at room temperature, and the pressure test is carried out on April 12 in Beijing.

Recently, some scientific research and construction units in China have believed that the equivalent curing age of the structural entity with the same conditions during winter construction can also be the same as that of normal temperature, but at this time, sub-zero degrees should not be counted, and it is not subject to the restrictions of 14 days and 60 days.

Beijing and some construction units across the country further proposed that not only can the 600 degree day method still be adopted (below zero degrees are not counted, and the 14-day and 60-day restrictions can be cancelled), but also the test block of 28 days of winter cultivation to normal temperature can be used to approximate 600 degree days. These methods are for reference.

Freezing critical strength test block.

During winter construction, the freezing critical strength test block should be retained, and the antifreeze covering measures can be removed only after it is qualified.

Freezing critical strength test block strength requirements: the freezing critical strength of silicate cement and ordinary silicate cement is 30%, slag silicate cement, pozzolana silicate cement, fly ash silicate cement, composite silicate cement must reach 40%, and C10 test block must be reached.

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.

Artificially create certain humidity and temperature conditions, so that the newly poured concrete can be normal or accelerate its hardening and strength growth. The fact that concrete can gradually harden and increase in strength is the result of cement hydration, which requires certain temperature and humidity conditions. If the surrounding environment does not exist for such conditions, the concrete needs to be cured manually.

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.

After the solution volatilizes, a thin film is formed on the surface of the concrete, which isolates the concrete from the air, prevents the evaporation of water in the concrete, and ensures the normal hydration of the cement.

1. The difference between standard maintenance and maintenance under the same conditionsStandard maintenance refers to the maintenance of the test block in an environment with a temperature of 20 3 and a relative humidity of more than 90%.

2. When there is no standard curing room in front of Li Erect, the concrete Huida specimen can be cured in non-flowing water with a temperature of 20 3.

3. The pH value of water should not be less than 7. The strength of curing for 28 days under standard conditions is used as the basis for the acceptance assessment of concrete strength.

The strength test should be carried out when the equivalent curing age is reached.

The same condition means that the maintenance conditions of the concrete clump soil test block are consistent with the maintenance conditions of the structure. After the mold is dismantled, it should be placed in an appropriate position close to the corresponding structural component or structural part, and the same maintenance method should be adopted.

The equivalent curing age refers to the age calculated by Zheng Bi under the same condition of curing and the intensity of the specimen at the age of 28 days.

The equivalent curing age should be determined according to the principle that the strength of the specimen cured under the same conditions is equal to the strength of the specimen at the age of 28 days under standard curing conditions.

The equivalent curing age of the natural curing specimen under the same conditions and the representative value of the corresponding specimen strength should be determined according to the local temperature and curing conditions according to the following provisions:

1. The equivalent curing period can be taken according to the age corresponding to the daily average temperature when the cumulative daily temperature reaches 600 ·d, and the age period of 0 and below is not included; The equivalent curing age should not be less than 14 days and should not be greater than 60 days;

2. The strength representative value of the curing specimen under the same conditions should be determined according to the strength test results according to the provisions of the current national standard "Concrete Strength Inspection and Evaluation Standard" GBJ 107, and then multiplied by the conversion coefficient; The conversion factor should be taken as, and it can also be adjusted appropriately according to the local test statistics.

That's what I feel. Hope it helps. Refer to GB50204-2002.

1. The difference between standard curing or swift and the same condition curing is that the standard rotation culture and protection system refers to the temperature of the test block at 20 3 and relative humidity.

Maintained in more than 90% of the environment.

2. When there is no standard curing room, the concrete specimen can be cured in non-flowing water with a temperature of 20 3.

3. The pH value of water should not be less than 7. Under standard conditions, the wax is only used for 28 days of strength, as the strength of concrete.

The basis of the acceptance assessment.

The curing time of concrete made of ordinary Portland cement is not less than 14 days; The curing time of concrete mixed with slag cement and pozzolane cement is not less than 21 days. Lu loss.

Related introductions

1. When the concrete reaches the initial setting and the expansion joint is cut, use a high-pressure water gun to remove the expansion joint and the sawdust and other residues on the panel;

2. The curing film is arranged in echelons on the pavement, and the overlap width of the two adjacent membranes is not less than 50mm.

3. Take a distance of about 10m as a laying stage for the curing film, repeat the following process: sprinkle water first until the thickness of the free water on the pavement is 3mm 4mm, and roll the arranged curing film forward on the pavement to make the polymer absorbing material in the membrane fully absorb water to a thickness of 5mm 10mm.

4. During the whole laying process, the overlap width of the two adjacent membranes should always be kept above 50mm.

5. There is lap glue on both sides of the membrane, which can realize the pasting of membrane and film lap joint; In order to prevent the lack of adhesive adhesion from forming a gap and forming a wind tunnel, which affects the quality of health care, a transparent glue with a width of 50mm can be used to paste the film lap joint.

6. In order to prevent the curing film from being blown up by the wind or washed away by heavy rain during the whole health period, a small amount of cement blocks or aggregates should be pressed. Especially for membranes paved in the center of the separator and on the shoulder, it must be compacted.

7. The membrane should cover the edges of the side walls on both sides of the concrete block slab, and reserve 100mm 200mm pressed sand and gravel for use.

8. At the expiration of the health care period, the uncovered curing film can be retained, which can be used for the initial health coverage before the expansion joint is cut after concrete paving, so as to reduce the cost of health care and improve the health quality of the stool by reusing the old.