Does Muriatic Acid Dissolve Concrete? (Solved)

muriatic acid

Muriatic acid is strong enough to dissolve the surface layer of concrete, the reaction between the muriatic acid and the concrete is what causes the concrete to dissolve, dissolving part of its structure.

The main component of concrete is calcium compounds, most of which are limestone aggregates, which react chemically with muriatic acid to form calcium sulfate, and the structure is destroyed.

To put it more simply, concrete is very alkaline and is quite susceptible to reactions with acids.

Substances such as strong acid can quickly corrode cement. For example, sulfuric acid and hydrochloric acid, hydrochloric acid will chemically react with Ca(OH)2 in cement, and the resulting compound may dissolve in water or expand in volume and cause cement damage.

Others Such as sulfate (sodium sulfate, potassium sulfate) when the sulfate penetrates into the cement stone structure, it will interact with the hydroxide in the cement stone.

The application of Muriatic Acid (Hydrochloric Acid) in construction is a widespread practice to remove the hardening solids from stuccoed surfaces, which are not visible, and from the brick surfaces which are visible, a necessary process because they act as anti-adherents, however, it is suggested to use only water (this is done in Europe and the USA).

In construction, using muriatic acid has its pros and cons, although the acid can weaken the concrete structure. One positive use, for example, is to create anchoring surfaces on very smooth floors for floor coating applications.

I have used it this way before applying any acid concrete stain, the floor is washed with muriatic acid to create more porosity in the concrete. Muriatic acid in the wrong way can have several negative effects on the concrete.

Can muriatic acid remove concrete?

Many people in the construction industry use a muriatic acid mixture to clean concrete debris from surfaces. Muriatic acid can be effective in removing cement, although it does not affect sand, which should be cleaned in other ways.

However, cleaning surfaces with muriatic acid is not advisable because it can be counterproductive. Some surfaces such as bricks, for example, are very absorbent, if they are washed with muriatic acid, part of it will not be able to come out with the washing.

The acid will remain inside them, damaging the bricks and the mechanical properties of the bonding mortar over time.

What are the effects of muriatic acid on cement?

Muriatic acid destroys only the cement that is the binder of the sand, leaving part of it loose on the surface, reducing its surface mechanical properties. Muriatic acid stops the setting process if applied before the classic 28 days.

How long is muriatic acid left to work?

After wetting the brick or concrete surface to be cleaned with muriatic acid and taking special care not to splash, the muriatic acid should be left to act on the surface for at least 10 minutes.

Remember that the chemical process between the acid and the cement is slow and gradual, this time is more than enough for the muriatic acid to act on the surface.

Does muriatic acid dissolve sand?

Muriatic acid does not react chemically with sand to produce a solvent reaction, sand is composed of very fine particles of rocks and minerals (silicates) so it does not dissolve.

If you touch the sand with your hand, it has a hard and rough texture, it looks like small pieces of stone, which prevents it from being diluted in water, unlike cement.

The muriatic acid has no space to make a chemical transfers in the sand and alter its system, therefore it cannot dissolve it. This is visible when muriatic acid is applied to concrete, it dissolves everything and the sand remains intact.

How to loosen solidified cement in walls or pipes?

In pipes covered with cement, you can use half a cup of muriatic acid in a pure state, and let it act for at least 10 minutes.

After this, a flexible guide should be introduced to remove the softened cement.

The soluble alkali in high-alkali cement is usually expressed in Na2O equivalent. It is mainly derived from clay and mixed materials used to produce cement.

A proper amount of soluble alkali is beneficial to promote cement hydration and is more conducive to the early strength development of concrete.

Tests have shown that The fluidity of cement concrete increases with the increase of alkali content. But it reaches a certain amount of water.

The commonly used method in engineering is to use oxalic acid or cement dissolving agent. For exterior wall tiles or exterior wall paint with cement or concrete, you will choose to use oxalic acid plus a wire brush and shovel for treatment.

Oxalic acid has an effect, but the effect is average Normally, the price is very cheap. If the pipe is blocked by grout or concrete, a cement dissolving agent is usually chosen.

Another known method for removing cement from surfaces is by applying phosphoric acid or trisodium phosphate to the concrete surface to be cleaned and using the mixture with water recommended by the respective manufacturer.

A brush is used to scrub the acid into the concrete. These are weaker acids that can easily dissolve the respective amount of concrete.

After approximately one minute of immersing the concrete in these acids, the concrete is scraped to be removed with a sharp spatula.

Can cement residues be removed with white vinegar as a substitute for muriatic acid?

Although white vinegar is acidic, the level of acidity it contains will not be sufficient to remove solidified cement residues in considerable accumulation, However, white vinegar works well to remove cement residues at the surface level and low cement density.

Consumer white vinegar has an acidity percentage ranging from 3% to 5% while cleaning white vinegar has 8% acidity, which is really too weak to remove cement stains.

After the cement hydrates and hardens, the products produced are mainly calcium silicate gel, calcium hydroxide, and calcium sulfoaluminate, which are alkaline.

The acidic substance and calcium hydroxide in the cement will have a neutralization reaction.

Usually, a cement remover is made of acids, such as phosphoric acid and oxalic acid, which will not be corrosive to the surface of the paints in a short time and are effective in softening and removing solidified cement.

How to soften cement?

Generally, the most commonly used to soften cement for subsequent cleaning are products created for this purpose, these products come in liquid form and are composed of solvents that are responsible for softening the cement or concrete to facilitate their removal without damaging the surfaces to be cleaned.

They are used to remove dirt that may remain after work, either on the floor, walls, or machines.

How to neutralize muriatic acid on concrete

Since muriatic acid can cause staining of cement, as well as damage to steel, it can be neutralized with a mixture of baking soda and water in a ratio of one cup of baking soda to one gallon of water.

Muriatic acid residues are neutralized with alkaline materials, especially powders. Acids react with alkaline materials dramatically, causing effervescence and boiling.

Baking soda is the substance most commonly used to neutralize acids, but other materials, such as garden lime and soda ash, can also be used.

How to clean a brick wall with muriatic acid?

Using acid to clean bricks is very effective when it comes to cleaning red bricks on the outside of the house, and it is very useful if you need to remove stubborn stains from the surface, such as cement residue that can ruin the aesthetics of the wall. Follow the steps below:

  • Mix one part of muriatic acid and 9 parts of water, depending on the size of the wall.
  • Thicker stains should be removed with a stiff brush or broom. Then, wet the rest and remove it using a spatula.
  • Leave the mixture on the bricks for about 10 minutes.
  • Rinse with a jet of pressurized water, using a pressure washer or a hose.

How is muriatic acid applied for cleaning?

Muriatic acid is always used diluted because as it is very strong it corrodes ceramics and floors. It should always be diluted in water in a quarter bucket of water, apply a jet and pass with a broom on the floors to clean the joints and with a brush, for bathrooms.

Is concrete sensitive to acids?

Concrete is not acid-resistant due to its chemical composition alone, but it can be made acid-resistant through appropriate additives and the choice of raw materials.

The concrete technology for achieving increased resistance to acid attack is based on two essential principles, the water-binder ratio ( w / c value ) and the impermeability of the cement stone.

The lowest possible w / c value in the range of 0.35-0.40 with cement contents of 340 + 20 kg / m³ leads to concrete compressive strengths of approx. 60 N / mm² and the associated low capillary porosity result in a high level of concrete tightness.

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