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Hydrogen Peroxide in Concrete Production
Hydrogen peroxide is used in the production of porous concrete and ceramics. In certain reactions of peroxide, or during peroxide decomposition, gas is released, and this property is the basis for producing porous materials, such as foam rubber.
The main advantage of peroxide is that gas is released without additional heating, and ordinary water is formed as a result.
In construction, in some cases it is necessary to increase the insulating properties and/or weight of a structure (for example, a building or part of it). This can be achieved by using porous blocks.
To do this, in America, expanded perlite or a similar lightweight filler material is added to concrete.
In the mid-20th century, Germany conducted experiments to produce porous materials with improved properties from cement mortars using hydrogen peroxide in the production process. The technology differed slightly for different fillers and depending on the required properties.
The starting mix was approximately as follows (materials are added in the order indicated):
- 0.6 tons of sand (fine-grained);
- 0.3 tons of cement;
- Water as needed (depending on the moisture content of the other components);
- 3.5 L of 40% hydrogen peroxide;
- calcium hypochlorite (the amount is calculated based on the reaction).
It turned out that using materials that accelerate the decomposition of the peroxide did not provide improvement.
Calcium hypochlorite reacts as follows:
CaOCl2 + H2O2 -> CaCl2 + H2O + O2.
The weight of blocks produced using this technology equals 1, compressive strength is 25-30 kg/cm2, and the insulating capacity exceeds that of ordinary blocks by 2-3 times. This technology was tested by the German army during the war.
When the amount of hydrogen peroxide was doubled and approximately 0.7% (calculated on the dry weight of the sand and cement) of wood shavings was added to the mix at the same time, the block weight equals 0.5, with a compressive strength of 20 kg/cm2.
Porous gypsum blocks were also tried using a peroxide decomposition accelerator. As a result, the blocks had a weight of 0.3 and a compressive strength of 4 kg/cm2.
Recent Patents Describe Similar Technologies.
The standard recipe consists of (in various proportions):
— clay (cement),
— gypsum (or without it),
— water,
— a small amount of a wetting agent (probably a surfactant to increase adhesion),
— hydrogen peroxide,
— caustic soda (used to raise the pH to 8-10)
— a peroxide decomposition accelerator (e.g., manganese sulfate).
Using hydrogen peroxide to produce porous concrete has a significant downside — poor adhesion (compared to normal) with metal reinforcement when pouring reinforced concrete. This occurs due to the formation of a gas film at the metal/concrete boundary during the decomposition of the peroxide solution.
A more detailed description of the Hydrogen peroxide product is here.
Other articles on the use of peroxide — for pools, in textile production, for wood bleaching.
Article on anti-freeze additives for concrete.
To buy Hydrogen peroxide, call us right now at (495)133-02-40, (495)407-17-86!
Or send a request to order@chimko.com
