DAMAGED CONCRETE . BREAK THROUGH CONCRETE TO ENSURE ADEQUATE ADHESION
Concrete damage may be the start of serious problems. The issue with concrete is that you can never be sure how a blow will affect it.
Harder aggregates are discharged with ease, along with fine dust and cement paste. Concrete’s compressive strength varies, unlike that of steel. Consequently, blasting does not result in an anchor spray pattern or a consistent surface profile. The surface of the blasted concrete is a crater filled with deep veins and pores.
The repair mortar, concrete overlay, and coatings must melt and permeate the substrate’s capillary network to guarantee correct adhesion. Any clogged mesh is exposed during the blasting process, which also roughens the concrete terrain and makes the aggregate visible.
How can a blaster determine whether he has measured the depth in micrometers and whether he has attained a specified surface profile without peaks and valleys to apply tape to? What is the definition of a concrete profile?
There are further problems. In addition to being thoroughly cleaned, a properly prepared concrete surface needs to be intact and free of impurities. However because concrete is rather porous, pollutants frequently seep far below the surface, weakening the substrate to a point where blasting equipment cannot reach. The only part of the hardened cement mass that needs to be removed in other applications, like decorative surface treatments, is the friable layer. If the blasting process is too strong or too weak, what should you do?
These and other issues are addressed in this handbook on concrete surface preparation. Then, you must understand how and why concrete might sustain damage as well as how to fix it.
BROKEN CONCRETE Immaculate Concrete
The adhesion between damaged concrete and coatings, fillers, or repair mortar can be maintained. Nevertheless, the damaged concrete will pull away from the ceiling when pressure is applied. Concrete damage indicators such as micro-cracks, blisters, flaking, or delamination need to be filled in and cleaned before surface treatment.
DAMAGED CONCRETE. Six Indices of Cracked Concrete
Visible cracks
One of the most noticeable indicators of concrete degradation are visible fractures, which can have several reasons. The quick loss of surface water during the curing process is what leads to surface cracks. If you place it on a subfloor, the ceiling may split in two. Cracks that become visible right away from heavy loads or impacts, or micro-cracks that eventually become obvious, can be caused.
DAMAGED CONCRETE Tiny fractures
Micro-cracks are measured on a micrometer scale and are imperceptible to the unaided eye. They are brought on by freezing and thawing, temperature variations that happen during cement hydration, overloading, impact from falling weights, and impact equipment like jackhammers and hammers. When a network of micro-cracks forms close to the surface, pressure marks result. The aggregate is shown when the broken concrete crumbles.
DAMAGED CONCRETE. Bubbles
Bubbling happens when air bubbles get trapped below the surface and the concrete cannot escape, for example, because of premature surface drying by the wind, the use of a mix that is too viscous and seals the surface too quickly, or premature trowel application of putty to the concrete.
Concrete
When water freezes in the concrete’s pores and capillaries, sparing takes place. The cracked mortar breaks from the surface and reveals the aggregate when the hydraulic pressure of the growing ice surpasses the concrete’s fracture strength.
Dirt and sparing are comparable, but sparing expands farther into the concrete. The surface fractures into bigger pieces as a result. Common causes include carbonation-induced corrosion of the reinforcing steel, excessive heat causing water vapor to expand very quickly, poorly constructed joints, and larger fissures.
DAMAGED CONCRETE. Arrangement
When the finish is applied before the concrete can allow air and water to leak out, it causes delamination, which is characterized by a hollow horizontal level underneath the surface. When the area of delamination separates from the concrete slab due to traffic or strong loads, the aggregate is exposed.
Broken concrete. Six Reasons Why Concrete Gets Damaged
The process of carbonation
When carbon dioxide combines with moisture and calcium hydroxide in cement and permeates the surface through pores and micro-cracks, carbonization takes place. Calcium carbonate is then formed as a result of this. The concrete first hardens as a result. But it also results in a pH value decrease from 13 to 8. Because of this decrease in alkalinity, the deposited Steel reinforcement is prone to rust.
Reinforced concrete corrosion
Rust, which is made of hydrated iron, is heavier than the steel it replaces. Tensile tensions brought on by the expanding mass of rust generate fissures in the concrete, which eventually peel off.
DAMAGED CONCRETE. Chemical damage
Sulfates react with the hydrated components in the groundwater that seeps through the concrete and expands. Mechanical failure results from this. Chemicals can also disintegrate, degrade, and weaken cement paste.
Fire harm
Although concrete doesn’t burn, it does lose most of its elasticity, and flexural, and compressive strength when it becomes too hot. The flaking off of concrete can be caused by expanding water vapor trying to escape.
Overloading and its effects
Micro-cracks and fractures emerge in concrete when it is subjected to strong stresses, particularly impacts. Widespread micro-cracks can be produced by impacting tools.
DAMAGED CONCRETE. Too-wet concrete
Cement will seep to the top if there is too much water in the mixture. Cement grouting, shrinkage, cracking, and decreased pressure resistance result from the surface drying out before it sets.
Broken concrete. Finding Concrete Damage
Visual examination of the surface can assist in identifying the worst damage, which includes delamination, fissures, and Spalding. But sometimes it’s difficult to see how much concrete damage there is.
Using a hammer to tap is the simplest approach to identify weak areas. There is good compressive strength in the concrete when the hammerhead ricochets. The concrete needs to be removed if the hammerhead dents and pulverizes the surface.
Concrete deterioration can also be identified by running a screwdriver across the surface. The concrete is fine if the screwdriver leaves a bright white track behind. When a screwdriver is used to scratch the powder, the concrete becomes damaged.
It is more difficult to identify situations in which air, water, or unsaturated material has formed beneath the surface since the surface can still be sufficiently intact to pass the screwdriver or hammer test. But there are damages to the concrete structure. Areas with different densities can be distinguished by listening to the sound produced while tapping the concrete. These cavities can be found in vast regions by either utilizing equipment to fog the surface with a succession of chains or by passing a chain across the surface.
Removal can start as soon as the degree of concrete damage has been established.
DAMAGED CONCRETE: Concrete Damage Removal
It is advisable to use mechanical methods (described below) to remove the damaged layer if the majority of the concrete surface is damaged. A popular technique is to use a hammer, jackhammer, concrete hammer, or other hitting tool to break up the broken concrete in specific regions of the afflicted areas if that is necessary.
Starting in the middle of the weak spot and working your way out to the edges is great practice. But even when using a thin layer of epoxy or cement filler to repair holes or dents, sharp edges should be avoided: The coating eventually becomes too thin to completely cover the surface with a profile. Better tensile strength can be obtained by knocking off deep, sharp edges; nevertheless, an undercut or vertical edge works best.
It is recommended to create a right-angled edge around the damaged region using saw cuts when filling a dent or dents with concrete or another thick composite. A square edge is produced when you strike outward toward the edge because the surface material breaks off in the cut.
Broken concrete. Fixing Concrete Damage
The holes or voids can be repaired with concrete, mortar, putty, epoxy, or another repair solution once the damaged concrete has been removed. Furthermore, voids in concrete must be filled in order to maintain structural integrity.
The Use of Blasting in the Removal of Concrete
Two ways blasting operators can maneuver during the concrete removal phase.
Dust-filled pores line the smooth, vertical surfaces left behind by saw cuts. To provide a contact surface for the repair material, shot blasting procedures open the pores and roughen the surface.
Widespread micro-cracks are produced when impact instruments are used to remove damaged concrete. The goal of repairing a surface that has been compromised by micro-cracks is defeated. The best technique for eliminating surface micro-cracks is sandblasting.
Broken concrete. Fixing Concrete Damage
The holes or voids can be filled with concrete, mortar, putty, epoxy, or another type of repair solution after the damaged concrete has been removed. Furthermore, cavities in concrete must be filled to give an integrated.
How to clean concrete?
Our best concrete cleaning fluid is BETOFF-B, which easily removes all dirt. It is 100% biodegradable, does not stink, and does not suffocate during use.
How to dissolve cement and concrete dirt?
The best fluid for dissolving dried concrete is BETOFF (concentrate), which easily turns concrete into mud.
