Prevention and Treatment of Crack in Mass Concrete

2019-08-23 16:41:17

1 Grouting method

Generally, the grouting method is adopted to repair the integrity cracks of building the structure. This method mainly USES pressure equipment to pour some cementing materials into concrete cracks. After hardening, cementing materials can be closely connected with concrete to reinforce and seal. Polyurethane, cement, epoxy, etc

Often good cementing materials, the application is very wide, mainly through the method of caulking to seal the concrete cracks, in general, along the cracks gouge, in the groove for the laying of waterproof materials, through this method to seal the cracks.

Prevention and treatment of crack in mass concrete

2. Surface repair method

Surface repair is a common repair method. It has the advantage of convenient operation, in the structure of some does not affect the structure bearing capacity in the process of the surface crack treatment, application is very wide, usually under the condition of the structure of the surface of cement slurry, cement daub, or will apply in the concrete surface protection concrete such as asphalt, paint, and avoid further cracking, etc., usually under the condition of the glass fiber can be arranged on the fracture surface of paste, to control the crack.

(1) Cement mortar shall be applied on the surface

In order to further ensure that the surface, the improvement of the performance of the waterproof in cement mortar into a certain amount of ferric chloride waterproofing agent, has the very good effect, so in after finishing the mortar on the surface of plastic film covering, so can effectively be combined with concrete and mortar, and can be used to support the template, extrusion screw tight, for

Some concrete has waterproof requirements, can use cement slurry and 1∶2 cement mortar for alternating daub, in general, need to daub 3~5 times, to form a waterproof effect of the rigid layer, after daub 3~5 times, to cover, and then through the way of sprinkling water for curing.

The concrete cracks around the corresponding surface gouging, and wet water, and cleaning or chiseling along the cracks into a depth of 15~20mm, width of 150~200mm groove, and brush a layer of cement mortar, then through 1∶2 cement mortar daub, the number of control in 2-3 times, the thickness of mainly in 10~20mm.

(2) Apply epoxy cement on the surface

In the process of cracks of concrete workability, need through the scraper and brush dipped in a small amount of cement, evenly over the surface of the fracture surface, for some of the slit width is relatively small and less quantity is not very concentrated fracture, can be treated in this way the, upon completion of repair, can use sandpaper, steel wire

Brush to clean and dry the oil, using acetone or xylene, and preheat it with a blowtorch if the surface is moist.

(3) Glue glass-silk cloth through an epoxy slurry

Firstly, epoxy resin adhesive is treated and coated with 1~2 layers of glass fiber cloth. Before using glass fiber cloth, the glass fiber cloth needs to be boiled in alkaline water for 0.5~1h, which can remove the oil and wax and improve the bonding effect. Secondly, in the second primer process, after 24h of natural curing, the substrate can be uniformly coated, followed by the laying of glass fiber cloth. If two layers are needed, one layer shall be affixed first and compacted, and then the second layer shall be uniformly affixed and the cloth width of the second layer shall be 10~12mm wider than that of the first layer, to facilitate the edge holding process.


3. Mass concrete structure design

First of all, in the structural design, designers should set up the large-volume concrete structure reasonably, and reduce the engineering volume and the overall hydration heat level on the premise of ensuring the construction demand and quality basis. For example, for part of the non-critical stress structure part can be hollowed out part of the concrete volume, optimize and improve the foundation structure construction soil

The square weight scheme provides the necessary infrastructure stability support for construction projects, thereby reducing the volume of concrete structures. In addition, studies have shown that the temperature stress is dependent on the structure boundary layer effect on building structure applied load, therefore, in the mass concrete engineering structure design, designers should pay attention to the boundary constraint condition of optimization, the temperature stress effects obvious geological conditions, should according to concrete structure setting sliding layer, thus weakening the temperature load stress restraint, avoid excessive load form the crack problem.





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