Concrete defects: mechanical, operational and climatic.

During operation, a variety of defects in reinforced concrete structures may occur. It is very important to identify problem areas in time, localize and repair the damage, since a significant part of them is prone to expansion and aggravation of the situation.

Below we consider the classification of the main defects of the concrete pavement, as well as a number of tips for repairing it.

Factors that affect strength

Before analyzing common defects of concrete structures, it is necessary to understand what may be their cause.

Here the key factor will be the strength of the frozen concrete solution, which is determined by the following parameters:

• Composition of concrete. The higher the grade of cement entering the solution, and the stronger the gravel that was used as a filler, the more resistant the coating or monolithic structure will be. Naturally, when using high-quality concrete increases the price of the material, because in any case we need to find a compromise between economy and reliability.

Note! Excessively strong compositions are very difficult to process: for example, to perform simple operations may require costly cutting of reinforced concrete with diamond circles. That is why overdoing with the selection of materials is not worth it!

• Reinforcement quality. Along with high mechanical strength, concrete is characterized by low elasticity, so when exposed to certain loads (bending, compression) it can crack. To avoid this, steel reinforcement is placed inside the structure. From its configuration and diameter depends on how resistant the whole system will be.

• Surface permeability. If a material is characterized by a large number of pores, then sooner or later moisture will penetrate them, which is one of the most destructive factors. Especially detrimental effect on the state of the concrete pavement temperature drops, in which the liquid freezes, destroying pores by increasing the volume.

In principle, it is these factors that are decisive for ensuring the strength of the cement. However, even in an ideal situation, sooner or later the coating is damaged, and we have to restore it. What can happen in this case and how we need to act is described below.

Mechanical damage

Chipped and cracked

The most common defects are mechanical damage. They can occur due to various factors, and are conditionally divided into external and internal. And if a special device, a flaw detector for concrete, is used to determine the internal ones, then problems on the surface can be seen on their own.

Here the main thing is to determine the reason for which the malfunction arose, and promptly eliminate it. Examples of the most common damage for the convenience of analysis, we structured in a table:

As can be seen from the analysis of the causes, the occurrence of some of the listed defects could have been avoided. But mechanical cracks, chips and gouges are formed due to the operation of the coating, so they just need to be periodically repaired. Maintenance and repair instructions are provided in the next section.

Prevention and repair of defects

To minimize the risk of mechanical damage, first of all you need to follow the technology of arrangement of structures made of concrete.

Of course, this question has many nuances, therefore we will give only the most important rules:

• First, the concrete class must comply with the design loads. Otherwise, the savings on materials will lead to the fact that the service life will be reduced several times, and for repairs it will be necessary to spend manpower and money much more often.
• Secondly, you need to comply with the technology of pouring and drying. The mortar requires high-quality compaction of concrete, and when hydrated, the cement should not suffer from a lack of moisture.
• You should also pay attention to the terms: without using special modifiers to finish the surface earlier than 28-30 days after pouring, it is impossible.
• Third, the coating should be protected from excessively intense impacts. Of course, the load will affect the state of concrete, but in our power to reduce the harm from them.

Note! Even a simple limitation of the speed of traffic in problem areas leads to the fact that defects in asphalt concrete pavement occur much less frequently.

Also important is the timeliness of the repair and compliance with its methods.

Here you need to act on a single algorithm:

• The damaged area is cleaned from the fragments of the solution, breakaway from the main mass. For small defects, you can use brushes, but large-scale chips and cracks are usually cleaned with compressed air or sandblaster.
• Using a saw on concrete or perforator, we embroider the damage, deepening it to a durable layer. If we are talking about a crack, then it needs not only to deepen, but also to expand, in order to facilitate the filling of the repair compound.
• Prepare a mixture for recovery using either a polyurethane-based polymer complex or non-shrink cement. When eliminating large defects, so-called thixotropic compounds are used, and small cracks are better to be repaired with injection molding means.

• We apply repair mixture for damage, after which we level the surface and protect it from stress until the product is completely polymerized.

In principle, these works are easily done by hand, therefore we can save money by attracting craftsmen.

Operational damage

Drawdowns, dusting and other problems

Specialists distinguish the so-called operational defects in a separate group. These include the following:

All of the above disadvantages arise either as a result of a violation of technology, or in case of improper use of the concrete structure. However, eliminating them is somewhat more difficult than mechanical defects.

Recovery & Recovery Tips

As in the previous case, the main recommendation will be strict adherence to the technology of arrangement of concrete structures:

• First, the solution must be poured and processed according to all the rules, preventing its separation and peeling during drying.
• Secondly, it is equally necessary to prepare the base well. The tighter we tamp the soil under the concrete structure, the less likely it will be sagging, deformation and cracking.
• To prevent concrete from cracking, a damper tape is usually mounted around the perimeter of the room to compensate for the deformations. With the same purpose, seams with polymer filling are arranged on large-area screeds.
• Also, the appearance of surface damage can be avoided by applying reinforcing polymer-based impregnations to the material surface or “ironing” the concrete with a fluid solution.

Chemical and climatic effects

A separate damage group consists of defects that have arisen as a result of climatic exposure or a reaction to chemicals.

These include:

• The appearance on the surface of divorce and bright spots - the so-called efflorescence. Typically, the cause of the formation of saline plaque is a violation of the moisture regime, as well as the ingress of alkali and calcium chloride in the composition of the solution.

Note! For this reason, in areas with highly carbonate soils, experts recommend using imported water to prepare the solution. Otherwise, whitish bloom will appear within a few months after pouring.

• The destruction of the surface under the influence of low temperatures. When moisture gets into the porous concrete, the microscopic channels in the immediate vicinity of the surface gradually expand, because when it freezes, water increases in volume by about 10-15%. The more often freezing / thawing occurs, the more intensive the solution will be destroyed.
• To combat this, use special anti-frost impregnation, as well as cover the surface with compounds that reduce porosity.

• Finally, reinforcement corrosion can also be attributed to this group of defects. Metal mortgages begin to rust in places of their exposure, which leads to a decrease in the strength of the material. To stop this process, before filling the damage with a repair compound, the reinforcing bars must be cleaned of oxides, and then treated with an anti-corrosion compound.

Conclusion

The defects of concrete and reinforced concrete structures described above can manifest themselves in very different forms. Despite the fact that many of them look quite harmless, when detecting the first signs of damage, it is worth taking appropriate measures, otherwise the situation may deteriorate sharply over time.

Well, the best way to avoid such situations is strict adherence to the technology of arrangement of concrete structures. The information presented in the video in this article is another confirmation of this thesis.