Advantages of 1. 1

Prefabricated components of prefabricated buildings can be manufactured in the factory and then transported to the construction site for installation. The whole installation process is simple, which can shorten the construction period to a certain extent. Factories can use mechanical equipment to produce prefabricated components to ensure the quality of prefabricated components; Compared with the construction equipment on the construction site, prefabricated construction equipment is used less, the rental cost of construction equipment is lower, and the workload on the construction site is less, which is more conducive to environmental protection.

1.2 Disadvantages

At present, the design of prefabricated components in China is relatively backward. A large number of bolts and embedded parts are needed for prefabricated components. There is still a big gap between China's transportation technology and production equipment and developed countries, so the scale of prefabricated components is not very large. In the process of using prefabricated components, vertical transportation machinery (large lifting machinery) is needed.

2 Precast component construction process and key points

2. 1 Reasonable Laying of Steel Bottom Formwork

When precast members are constructed, steel bottom formwork is usually placed at the corresponding position of reinforced concrete structure foundation. At the same time, according to the construction conditions of precast members, angle steel with appropriate size is used as formwork keel, and the size of each formwork is required. Effectively control its specific value and ensure the rationality of its structure. When pouring formwork keel concrete, steel plates with appropriate thickness must be covered first, and then laid. After laying the thick steel plate, the surface of the steel plate should be cleaned with a grinder as soon as possible. Then putty is used for putty treatment, and the protruding part of the steel plate joint is polished with appropriate equipment to ensure the flatness of the steel plate bottom plate [2].

2.2 Scientific production of steel side formwork

For prefabricated members, steel side formwork is usually composed of steel plate and section steel. Then the rib groove and sleeve hole are made in the correct position of the side form. When operating the hole, the locating pin hole should be scientifically designed in the correct position between the side die and the lower die, and the side die and the side die, and the special locating pin should be flexibly assembled and fixed with the corresponding die head. For the same type of prefabricated members, the same side formwork can be used in actual construction. When the corresponding positions of doors and windows, embedded parts and reserved holes change, the corresponding local mold construction should be carried out to ensure the steel edge. The overall quality of formwork can meet the design and construction requirements of prefabricated components.

2.3 Carefully processed steel skeleton

Before processing the reinforcement cage, the protective layer spacing should be set reasonably, and then the reinforcement cage should be processed according to the pre-designed processing drawings. First of all, the main reinforcement and grouting sleeve should be well done and connected with collars. In the process of steel frame construction, it is necessary to ensure the accuracy of the specifications and positions of embedded parts, ribs and steel bars in the formed steel frame, so as to ensure the firmness and stability of steel bars in various parts. A little stiff. Finally, after the reinforcement cage is reinforced, the thickness of the protective layer should be the same as that of the main reinforcement. If necessary, special PVC restrictions can be customized according to special manufacturers. On the basis of ensuring the uniformity of gaskets, the spacing of gaskets should be controlled at about 1m, which can not only accurately ensure the quality of main reinforcement layer, but also prevent adverse effects on subsequent construction.

2.4 Installation of embedded parts

The underground part mainly includes: permanent structure underground part, temporary lifting and stacking underground part, electrical underground part, water supply and drainage underground part, gas underground part and ground wire underground part. In order to fix the insert, the hanger rod or the insert can be fixed on the lower die. Although this method can ensure the accurate positioning of embedded parts, inserting embedded parts into the side plate of the mold may cause deformation. Resulting in a deviation in the position of the buried part. Therefore, relevant inspectors need to carry out detailed inspection to ensure the accurate positioning of prefabricated parts. At the same time, the staff should strictly control the horizontal height and verticality of the components (the staff can set small grooves on the bottom of the template for the staff to check). After the assembly production is completed, workers can track the appropriate track and then guide the assembly to the inside [3].

2.5 Stacking of precast members

Precast members can be stacked horizontally or vertically. Wall panels usually need to be stacked vertically, and floors, roof panels and main components can be stacked horizontally or vertically. When the vertical stacking method is adopted, the ground should be tamped in advance, and concrete materials should be paved on the ground to avoid the rain from causing great influence on the road; In addition, in order to avoid bracket sliding, the pavement smoothness should be improved. When the bracket is used, prefabricated members are fixed on both sides, and the prefabricated members are kept in a vertical configuration. If the parts are placed horizontally, two pieces of wood or steel should be placed on a horizontal basis, and the same material blocks (6 pieces) should be placed on the top. Workers should ensure that these blocks are placed in the same position up and down.

2.6 transportation of prefabricated components

In order to prevent the prefabricated components from cracking and deformation during transportation, it is necessary to choose suitable transportation tools and gantry. At the same time, the loading and unloading of prefabricated components must be carried out by the staff in strict accordance with the relevant regulations, and must be carried out between the transport gantry and the vehicle, and appropriate cushioning materials should be set up. In addition, suitable wires or clamps are selected to fix prefabricated members to avoid collision during transportation. Employees must choose the transportation route according to the transportation plan, ensure the smooth and slow transportation process, and avoid braking as much as possible.

2.7 Key points of concrete pouring construction

Concrete pouring construction is the key link of precast member construction. The control of the construction site will directly affect the overall quality of the construction, including the following aspects: (1) Before pouring concrete, the construction personnel should carefully check the quality of embedded parts, steel bars and templates used in the construction to ensure that they meet the design requirements. (2) In the application of concrete mixing machinery, it is applicable to the construction list system. For example, if the concrete mixer on the front panel is not smooth concrete, it is necessary to carefully clean the mixer and thoroughly remove the residual water in the pipeline in the future concrete construction. In addition, the mixing time of smooth concrete is usually longer than that of ordinary concrete 15s or so. At the same time, the slump of concrete should be controlled at about 10cm, and the water cement ratio should be controlled at about 0.35 to ensure the good performance of concrete. This performance can ensure the quality of subsequent construction. (3) During the concrete vibrating construction, the construction personnel should adopt the construction principle of fast insertion and slow pulling, so as to ensure that the vibrating is symmetrical and even, and the moving distance of the vibrator is not more than 300mm, so as to avoid vibration leakage during the vibrating construction. For the vibrating part of each formwork concrete, the degree of compaction must be guaranteed. Specifically, the concrete will not continue to sink, or there are no visible bubbles in this area, and the surface will be submerged and become flat. When forming concrete, the corners of the formwork are mainly filled with solid concrete. Usually, the specific vibration time is controlled around 30s to avoid excessive vibration. Otherwise, it is easy to produce defects such as holes and honeycombs, and vibration should be avoided. Embedding, reinforcement and collision formwork. (4) After pouring concrete, the concrete surface should be leveled with special ground equipment to ensure its flatness meets the specified requirements. For example, the height difference of concrete surface within 2m should not exceed 3 mm. ..

2.8 Key points of concrete curing construction

After the initial setting of concrete, the hydration heat will be greater. If the temperature cannot be effectively controlled at this time, the temperature difference of precast concrete members will easily affect the construction quality, so concrete maintenance and construction must be done well. For example, after the concrete is finally solidified, some curing agent should be coated on the concrete surface, and water-saving construction is not needed. Or take measures such as covering the surface of the structure with thatch or sprinkling water to ensure the quality of concrete maintenance and construction. In addition, after dismantling all kinds of prefabricated members, the construction unit needs to reasonably treat the prefabricated members with local rough surfaces in combination with the user's construction regulations and requirements to ensure the surface of concrete prefabricated members. Smoothness is an important guarantee to ensure the quality and safety of subsequent construction.

3 Conclusion

The construction industry consumes a lot of resources and energy. The design, production, transportation and assembly of prefabricated components will affect the building quality. Therefore, any problems found by construction personnel in the construction process need to be dealt with in time to improve the construction quality of prefabricated components, promote the stable development of the construction industry and ensure the production quality of prefabricated components [4].

I believe that after the above introduction, everyone has a certain understanding of the construction technology of prefabricated components in prefabricated buildings. Welcome to Zhong Da for more information.

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