Although it is difficult to avoid the cracks of the laminated plate in engineering practice, measures such as maintenance during production, attention to mold removal time, reasonable stacking, use of special shelves, and standardized operation can greatly reduce the cracks of the laminated plate.

With the continuous development of precast buildings in Shenzhen, the quality problems of precast buildings can not be ignored.

When pouring the floor slab, the truss rebar can be used as the stirrup of the slab top rebar to control the rebar cover.

2、 Cracks in composite slabs Composite slabs are widely used as precast components in precast buildings, and the problems of cracks in composite slabs caused in the process cannot be ignored.

The truss reinforcement can connect the precast concrete and the cast-in-place concrete into a whole, increase the stiffness of the floor, and increase the shear of the composite surface; 2.

The height is too low, the clearance between the top chord reinforcement and the finished surface of the laminated plate is insufficient, and it is difficult to pipe the water and electricity pipelines; If the height is too high, the protective layer of the top reinforcement of the slab will be too small or the reinforcement will be exposed.

4、 Rough surface of precast components shall be set on the joint surface of precast components and post cast concrete, grouting materials and setting mortar materials when the concave and convex depth of rough surface of precast components is not enough.

This article will discuss the common problems and preventive measures of precast buildings in Shenzhen, hoping to provide some reference for the sustainable development of precast buildings industry.

5、 Cracks in light partition slats Cracks in light partition slats not only affect the beauty and use of buildings, but also affect the promotion and application of light partition slats.

Only by controlling all aspects of design, production and construction, and strengthening the professional skills training of workers, can various quality problems be effectively prevented…

Therefore, the laminated plates shall be produced in strict accordance with the component drawings, and the allowable error of the exposed height of truss reinforcement shall be controlled within [0.5] mm.

The effect of the protective layer is reduced, which accelerates the corrosion of the main reinforcement and finally destroys the precast members.

Insufficient production and maintenance of laminated plates, premature mold removal, excessive layers of transportation and stacking, non-standard hoisting, etc.

Cracks in the laminated plates will not only affect the structural safety, but also easily cause leakage.

There are many reasons for cracks in light partition slats, including poor material of the product itself, improper design and construction operation.

The rough surface of precast components is mainly made to increase friction, so as to make the connection between precast concrete and cast-in-situ concrete more fixed.

During the production of precast components, spacers shall be reasonably selected and set to ensure that the reinforcement is laid at the correct position and the thickness error of the protective layer is controlled within [- 3.3] mm, which can reduce the damage of precast components caused by the thickness problem of the protective layer.

Cast In Loop

However, the quality problems of precast buildings still exist.

The concave convex depth of the rough surface of the precast slab shall not be less than 4mm, and the concave convex depth of the rough surface of the precast wall end shall not be less than 6mm.

To avoid cracks in light partition slats, manufacturers of high-quality panels shall be selected, anti cracking joints shall be reasonably designed, and quality control of slats installation shall be strengthened.

During the fabrication of precast components, the depth of rough surface concavity and convexity will not be enough if the retarder is not applied, the quality of retarder is poor, and the operation is not standardized.

The technical disclosure shall be conducted before the fabrication of the precast rough surface.

In recent years, with its regional advantages, industrial characteristics and technical foundation, Shenzhen has achieved rapid development in precast buildings.

1、 The exposed height of the truss reinforcement of the composite plate As an important part of the composite plate, the truss reinforcement has the following functions: 1.

The construction scale of precast buildings has exceeded 60 million square meters, ranking the top in the country.

Too low or too high exposed height of the laminated plate truss reinforcement will directly affect the on-site construction.

The thickness of the protective layer of the precast component reinforcement is too small, which is easy to cause the exposed reinforcement or the surface concrete to fall off, the reinforcement to rust, the section to reduce, and the overall structural performance of the precast component to be damaged; If the protective layer of reinforcement is too large, many planned transverse cracks are likely to appear in the direction perpendicular to the main reinforcement.

will cause cracks in the laminated plates.

3、 The main function of the protective layer of the reinforcement of precast components is to protect the reinforcement and prevent the reinforcement from rusting.

At the same time, the necessary thickness can ensure the concrete’s grip on the reinforcement and make it meet the requirements of the design value.