Ask for help about the pouring time and curing time of the post pouring belt

concretePost-pouring tapeThe concrete on both sides can be poured after 28 days, and the curing time is 14 days, and the concrete on both sides of the waterproof concrete can be poured after 42 days, and the curing time is 28 days。The pouring time of the post-pouring belt should be selected when the temperature is low, and the cement or cement can be mixed with a trace amount of aluminum powder concrete, and its strength grade should be one level higher than the strength of the component.

The construction drawings of the post-pouring belt designed by the current design institute are not the same

The current code "High-rise buildings.

Technical Code for Concrete Structures" (JGJ3-2010), "Technical Code for Waterproofing of Underground Works" (GB50108-2008) and different versions of building structures.

In the structural atlas, there are detailed regulations on the structural requirements of the post-pouring belt. Since these norms and standards are written by different expert groups, their content and requirements are different, and each has its own emphasis, and there are inevitably some differences.

Post-pouring tape for underground waterproofing.

days to be constructed.

2. Use compensating shrinkage concrete, and the strength is not lower than that of concrete on both sides.

3. The maintenance time is 28 days.

Main structure concrete.

1. General curing for 7 days (silicate, ordinary silicate, slag) 2. Pozzolanic ash, fly ash, impermeability, admixtures, admixtures for 14 days.

The main structure is poured after the belt.

days to be poured.

2. Micro-expansion concrete, the strength is one grade higher than the original structure.

3. Curing for 15 days.

This should make sense.

According to the new standard in 2015, the concrete on both sides of the general concrete post-pouring belt can only be poured after 28 days, and the curing time is 14 days. The concrete on both sides of the waterproof concrete can be poured after 42 days, and the curing time is 28 days.

Please note that the two concretes are different concrete, one is ordinary concrete, and the other is waterproof concrete! Nong may not have paid attention to the premise.

The specification requirements for post-pouring tape are as follows:

1. The retention width of the post-pouring belt is generally 700-1000mm, and there are three common types: 800mm, 1000mm and 1200mm.

2. There are four types of joints in the post-pouring belt: straight seam, stepped seam, notch seam and X-shaped seam.

3. The steel bars in the post-pouring belt are fully disconnected and then lapped, and there are provisions for additional reinforcements to be set up without opening.

4. The supplementary pouring time of post-pouring concrete is not less than 14 days, some are not less than 42 days, some are not less than 60 days, and some are 28 days after capping.

5. The preparation and strength of the concrete of the post-pouring belt are required to increase the strength grade of the original concrete, and some require the pouring of non-shrinkage concrete of the same grade or improved level.

6. The maintenance time regulations are inconsistent, and there are several time requirements such as 7 days, 14 days or 28 days.

In order to prevent the harmful cracks that may occur in the cast-in-place reinforced concrete structure due to temperature and uneven shrinkage in the building construction, in accordance with the requirements of the design or construction specifications, temporary construction joints are left at the corresponding positions of the foundation bottom plate, wall and beam, and the structure is temporarily divided into several parts, and after the internal shrinkage of the components, the concrete of the construction joint is poured after a certain period of time, and the structure is connected into a whole.

The pouring time of the post-pouring belt should be selected when the temperature is low, and the cement can be poured or the concrete mixed with a trace amount of aluminum powder in the cement, and its strength grade should be one level higher than the strength of the component, so as to prevent cracks between the new and old concrete, resulting in weak parts. The retention of the post-pouring belt in the construction of the super-long foundation floor is conducive to solving the cracks of the floor caused by the temperature stress of the super-long structure and the differential settlement stress of the high and low layers, but it affects the structural safety and waterproof quality. The strength grade of the concrete filled in the post-pouring zone must be one level higher than that of the original structure.

The curing time of concrete with post-pouring belt shall not be less than that after concrete pouring, the reason why it can gradually set and harden is mainly because of the result of cement hydration, and hydration requires appropriate temperature and humidity conditions, so in order to ensure that the concrete has suitable hardening conditions and its strength continues to grow, the concrete must be cured.

The concrete that has been poured is completed, should be before the final setting of concrete (usually within 8 12h after the concrete is poured), begin to carry out natural curing.

However, the "Technical Specification for Waterproofing of Underground Engineering" also stipulates that the waterproof concrete should be cured immediately after the final setting, and the curing time shall not be less than 14d.

Ordinary concrete is cured before final setting, but waterproof concrete is cured after final setting.

Why is that?

Because a layer of water-repellent film will be formed after the hydration reaction of waterproof concrete, it is this layer of water-repellent film that plays the role of waterproof and water resistance. Therefore, it is necessary to wait for the waterproof concrete to complete the hydration reaction before sprinkling water for maintenance, so that this layer of water-repellent film will not be damaged and the waterproof concrete will play a waterproof role.

For waterproof concrete, it must be noted that it should be cured immediately after final setting. Because if the curing is not timely, the moisture inside the concrete will evaporate rapidly, making the cement hydration incomplete.

The evaporation of water will cause the capillary networks to communicate with each other, forming a seepage channel, and at the same time, the concrete shrinkage increases, cracks appear, and the impermeability decreases sharply, or even loses the impermeability completely.

A summary of the concrete curing time is attached.

1. Ordinary concrete.

1) For the concrete that has been poured, natural curing should be started before the final setting of concrete (usually within 8 12h after the concrete is poured).

2) The standard curing age of the concrete specimen is 28d, and its compressive strength is tested.

3) After the concrete is poured: it will be covered and moisturized within 12 hours. The time of watering and curing shall not be less than 7 days for the concrete mixed with Portland cement, ordinary silica cement and slag cement, and shall not be less than 14 days for the mixing of retarding admixtures or impermeability requirements.

4) After the construction of the overall surface layer, the curing time should not be less than 7d, and the compressive strength should reach 5MPa before the master is allowed to walk.

2. Waterproof concrete.

After the final setting, it should be cured immediately, and the curing time should not be less than 14d.

3. Post-pouring tape. 1) The concrete should be covered within 12h after the concrete is poured for moisturizing and curing.

2) The post-pouring belt should be kept for at least 28 days, and the wet curing should be maintained for at least 15 days.

3) Waterproof construction of post-pouring belt: The age of concrete on both sides should reach 42d; The curing time is not less than 28 days.

4. Large volume concrete.

1) For large-volume concrete, the duration of moisturizing curing shall not be less than 14d.

2) Large-volume concrete: when ordinary Portland cement is used, the curing time shall not be less than 14d; When slag cement is used, the curing time of pozzolane cement shall not be less than 21d; After the final setting of waterproof concrete, it should be cured immediately, and the curing time should not be less than 14d.

The latest specifications for the pouring time of the post-pouring belt are as follows:

Basically, the concrete has solidified to start pouring after pouring the belt, during the solidification of the land potato concrete, it may take up to 28 days, after the main structure is completed and the settlement is stable, and then the pouring or the concrete on both sides has been burned into shape, and the time can be poured for about 60 days. Of course, the pouring belt after pouring should also be viewed according to the weather and temperature changes at that time.

It prevents the cast-in-place reinforced concrete, because of uneven settlement and some cracks, these cracks will have an adverse impact on the later building structure, so it is necessary to leave concrete belts in the corresponding positions such as walls and beams in accordance with the requirements of the design specifications.

The volume of newly poured concrete is unstable in the process of induration, and the built structure will expand when heated and shrink when cold. Most of the concrete induration shrinkage will be completed in the first 1 2 months after construction, and the effect of temperature changes on the structure is recurrent. When its deformation is constrained, temperature stress will occur inside the structure, and in severe cases, cracks will appear inside the component.

In the construction, the post-pouring belt is set up in the excessively long building, and the width of the joint is 700 1000 mm every 30 40 meters, and the steel bar in the joint adopts lap or straight bending method. After leaving the post-pouring belt, the deformation limit of the concrete due to temperature becomes smaller, which greatly reduces the effect of temperature stress.

How to use:

The retention time of post-pouring tape is generally not less than one month. During this period, the shrinkage deformation can be completed by 30% to 40%. The pouring time of the post-pouring belt should be selected in a period when the temperature is low (but it should be positive).

It can be used to pour cement or cement mixed with a trace amount of aluminum powder concrete, and its strength grade should be one level higher than the strength of the component, so as to prevent cracks between the new and old concrete, resulting in a weak concrete structure at the post-pouring zone.

The retention time of post-pouring tape is generally not less than one month. During this period, the shrinkage deformation can be completed by 30% to 40%. The pouring time of the post-pouring belt should be selected in the period when the temperature is low (but it should be a positive temperature), and the concrete with a trace amount of aluminum powder in the cement can be poured, and its strength grade should be one level higher than the strength of the component, so as to prevent cracks between the new and old concrete, resulting in the weakness of the concrete structure of the post-pouring belt.

Generally, the post-pouring belt is divided into telescopic post-pouring belt and settlement post-pouring belt, and the triangular post-pouring belt is generally poured in the concrete after the shrinkage is basically stable, and it can only be carried out after 60 days after the pouring is completed.

Pouring according to the design requirements, when the design is not required, at least 28 days are retained, and the waterproof post-pouring belt is constructed after the concrete age on both sides reaches 42 days.

Hello dear! Glad for your question! How long can it be cured after the pouring of the post-pouring belt is completed:

The normal curing time for post-pouring strips is 14 days, and for the concrete on the side of the pouring strips, it usually takes 28 days for curing. Due to the differences in concrete construction requirements, the specific curing time for the return to purification should be determined according to the situation of on-site construction. What are the precautions for concrete pouring 1, when the concrete is poured, it must be constructed with the corresponding formwork, when the height of the glue injection is greater than two meters, it should also be used for construction, preferably not greater than meters.

2. When pouring concrete, it must be used within 5 hours, because the concrete will deteriorate after 5 hours, if it is not used in this process, then do not continue to use the concrete, even if it is used in the later stage, it is very likely that Sun Zhi will cause some damage to the wall. 3. In the process of concrete pouring, we must use the stirring rod to stir continuously, so that the surface of the concrete can not produce any bubbles and slurry, and we can not let the concrete sink and then do this before we can carry out construction.