One study found that magnesium chloride, magnesium acetate, magnesium nitrate, and calcium chloride are more damaging to concrete than sodium chloride (Cody, Cody, Spry, and Gan 1996).
Calcium chloride, magnesium chloride and all salts do damage to concrete. Magnesium chloride and ammonium nitrate are especially bad – do not use these! If you have to use salt, use a small amount.
Concrete Corrosion refers to the degradation of concrete due to exposure to certain corrosive substances; usually sulfur compounds. Although concrete corrosion can also be caused by other factors as well, such as salty or acidic water, microbes, chlorides, nitrates, or fluorides.
As a gentler cleaner, bleach can't harm concrete's durable material. Aside from being an effective cleaner and stain remover, it also acts as a disinfectant to the concrete surface.
Concrete can be subjected to attack by various inorganic and organic acids including sulfuric, nitric, hydrochloric, phosphoric, acetic, lactic and so on. However sulfuric acid can be considered as the most common cause of deterioration of concrete structures, since attack by which can occur in many various ways.
Disintegration can be a result of many causes such as freezing and thawing, chemical attack, and poor construction practices. All exposed concrete is subject to freeze-thaw cycles, but the concrete's resistance to weathering is generally determined by the concrete mix and the age of the concrete.
Sodium hydroxide (NaOH), also known as sodium hydrate, caustic soda, and lye, is commonly used in oil refineries, manufacture of paper, paints, plastic, soaps, and many other common products. This caustic soda, being on the opposite end of the pH values scale from acids, also, will disintegrate concrete.
Over time, it can destroy concrete as the acid weakens its structure. This will cause scaling, pitting, peeling, and cracking. If the acid wash gets into the soil, it will evaporate on the surface but remain beneath the surface (just like it does with concrete).
Chemical Attacks
Not even non-porous surfaces are safe. Salts (both sulfates like epsom salt and chlorides like table salt) can react chemically with many minerals found in masonry and cement.
Hydrochloric Acid is used for etching concrete where grinding is not an option or cannot be carried out to prepare the floor for a new coating. Acid etching will remove most of the weak, milky layer of cement dust, lime and sand fines that can rise to the surface with over-wet concrete, poor curing or over-trowelling.
Salt eats concrete for breakfast, lunch, and dinner.
However, any chemical containing chlorides, including: sodium chloride, potassium chloride, calcium chloride etc.
Under 400 °C, the hydration products of concrete do not obviously decompose, the deterioration of concrete is mainly due to the high temperature vapor pressure; when the temperature exceeds 400 °C, the calcium hydroxide (CH), C-S-H gel and calcium carbonate (CaCO3) of concrete decompose, resulting in a decline of ...
These structures are often subject to a permanent process of physical and chemical degradation as a result of external aggression. In this context, this paper presents the different chemical causes of concrete degradation such as carbonation, alkali-reaction and sulphate reactions.
Alkali carbonate reaction (ACR)
ACR occurs when certain types of dolomitic limestone aggregates are used in concrete in the presence of high alkali portland cement. The products of this reaction are expansive and cause deterioration of concrete.
Scaling is one of the most common problems of concrete. In scaling, the surface layer of concrete gets deteriorated by getting peeled or by breaking off.
One of the main factors in concrete technology is permeability, the ability of concrete to resist water and chemical migration. Migration of salts, chlorides, sea water, and other aggressive chemicals can cause deterioration and cracking in concrete.
What Is the Best Tool to Break Up Concrete? The best tool for the job depends on the thickness of the concrete and your level of strength. A sledgehammer and pry bar are best for thinner slabs, while a jackhammer or chipping hammer works better for slabs over 3 inches.
White vinegar will not damage your concrete. However, leaving this solution for an extended period will damage the cement that binds the concrete together. Hence, you should be careful when using vinegar on your concrete, especially if you will use this solution on polished concrete.
DON'T paint or stain concrete in the first month.
It takes about a month for all of the water to get used up in the hydration process. Brush on paint too soon while moisture is still rising to the surface, and it can put pressure underneath the hard barrier of paint, causing it to peel away or break the bond.
Concrete & Mortar Dissolver. The advanced liquid formula dissolves and physically breaks down concrete by attacking the Portland cement, eventually reducing it to mush that is easy to clean off with a hose or pressure sprayer.
Sugar increases the setting time of cement up to 1.33 hrs at dosage level of 0.06% by wt of cement. There will be no effect on workability, compaction by the use of sugar as admixture in concrete. Higher long-term compressive strength is achieved in concrete by the use of sugar as admixture.
The sulfuric acid reacts first with the calcium hydroxide (CH) to precipitate gypsum (CaSO4 2H2O) on and below the concrete surface, which can induce tensile stresses in concrete, resulting in cracking and spalling [4].
Citric acid is an organic acid naturally present in fruits, one of the ingredients that can be used as a retarder in a concrete mixture. As retarder serves to slow the timing of concrete hardening.
Acids attack concrete by dissolving both hydrated and unhydrated cement compounds as well as calcareous aggregate. In most cases, the chemical reaction forms water-soluble calcium compounds, which are then leached away.
In a study on the effect of synthesis parameters on the compressive strength of fly ash-based geopolymer concrete, it was determined that the best NaOH concentration is 12 M in order to produce a high-compressive-strength concrete. The compressive strength increases as NaOH concentration is increased from 6 to 12 M.