The alkali-silica reaction, more commonly known as concrete cancer, is a detrimental swelling reaction that occurs over time in concrete between the highly alkaline cement paste and the reactive amorphous silica found in many common aggregates with sufficient moisture. Concrete cancer occurs when steel reinforcement within a concrete slab begins to rust. As the steel oxidizes, it expands and displaces the surrounding concrete, causing it to become brittle and crack, compounding the problem. Specific cancer refers to the spread (and worsening) of concrete chipping.
Concrete is porous, absorbing the acid created during the chipping process, accelerating corrosion and exposing the internal steel structure to air and water. Again, this speeds up the corrosion process and ultimately leads to significant and costly property damage. The concrete used in buildings is reinforced with steel and iron bars or meshes. When exposed to air and water (for example, through higher level leaks), a weak carbonic acid begins to form, and the rods begin to corrode.
Concrete is a porous material that can easily absorb the elements surrounding it, including this corrosive acid. Once corrosion begins, the steel expands, causing the surrounding concrete to crack, which is known as. Chipping can trigger a vicious cycle by further exposing the steel to the elements and accelerating the level of corrosion. Building Impact Leads to Tragic Compromise of Structural Integrity.
Flat concrete roofs are an example of a building structure that is particularly vulnerable to leaks and water-driven concrete cancer if they are not properly waterproofed. This process is what gives a structure to specific cancer. Concrete cancer occurs when concrete absorbs water and salt air, which oxidizes the steel it contains. When it expands, it cracks the concrete.
The material is usually poured around iron support or steel bars and mesh to reinforce concrete buildings. While this generally keeps the structure of a building high, this combination of materials can also lead to the development of cancer in concrete, especially in buildings with inadequate waterproofing or construction defects. Concrete cancer is defined as substantial deterioration when the metal inside is exposed to air and water. This causes a weak acid to form, which corrodes the metal and begins to expand, crack, or leak.
Concrete is one of the most common building materials in use today, and you'll most likely find it in just about any home or building. The structural engineer may recommend different solutions depending on the cause of concrete cancer. There are some telltale signs of specific cancer, and the most obvious is flaking itself. This solution consists of removing the concrete around the reinforcing bars and cleaning the steel before applying both the steel primer and a polymer-modified material.
If you have detected signs of concrete cancer in your building, consult a professional like Slabtec, who specialises in concrete cancer repair work and get advice on the type of repair work to be done. But even before visible cracks form concrete crumbling, internal wall leaks, expanding walls, definite bubbling, and rust spots can tell you what's going on inside the walls. Watch for signs such as concrete chips (cracks, etc.), rust spots that seem to leak from inside the concrete, bubbles from concrete plaster, or leaks that appear in raised concrete. Cracking accelerates the concrete cancer process by exposing more steel, significantly weakening the building.
The metal structure begins to expand and replace the concrete, causing chipping and, in a vicious circle, increasingly exposing the reinforcing structure to the air and water that caused the oxidation process in the first place. Repairing and filling small cracks will help stop the spread of concrete cancer, but the key to a successful remedy is timely and professional identification and treatment. So how can you detect if your building has concrete cancer? One of the first telltale signs is the presence of ferrous stains on the concrete surface. Regardless of whether the damage is severe or moderate, waterproofing and integral sealing after repair are essential to minimize the risk of concrete cancer in the building.
This is known as concrete cancer, the term used to refer to the oxidation of steel reinforcements that are contained within a concrete slab. Unfortunately, it can take many years before particular cancer becomes truly obvious; by then, the damage can be extensive.
Leave a Comment