Foam concrete is a kind of concrete with lightweight and has ideal strength. Because of the hollow structure in foam concrete, it has the function of absorbing heat and isolating sound.
The density of foamed concrete is 300-1200 kg/m3, and the thermal conductivity is between 0.08-0.3W/ (m ·K).
Foam concrete is widely used in CLC blocks, lightweight partition panels, roof insulation, floor cushion construction, floor heating backfilling, and other occasions.
At the same time, foam concrete is also a good sound absorption material, which can be used in highway sound insulation boards, sound absorption boards, and other fields.
Generally speaking, foam concrete is a kind of building material with multi-function, environmental protection, and economy, which has a wide application prospect.
The types of retarders include lignosulfonate and its derivatives, low molecular weight cellulose and its derivatives, hydroxy carboxylic acid (salt), organic phosphonic acid (salt), boric acid (salt), complex and so on.
The specific substances that can be used as retarders include dextrin, various types of starch, casein and some substances containing protein, as well as sucrose, glucose, calcium lignosulfonate or sodium salt, sodium carboxymethyl cellulose (CMC), carboxyethyl cellulose (CHC) and their mixtures. In addition, there are tartaric acid, potassium tartrate, calcium tartrate, calcium sulfate dihydrate, calcium sulfite, ferrous sulfate, boric acid, boric acid and tartaric acid, mixture of tartaric acid and sodium bicarbonate, sodium hexametaphosphate, disodium phosphate, trisodium phosphate, tetrasodium phosphate, disodium hydrogen phosphate, sodium pyrophosphate, alkyl phosphate, disodium ethylenediamine tetraacetate, various humic acids, etc.
According to the above analysis, sugar is also a kind of retarder. The general theoretical explanation for the role of sugar is that sugar can absorb tricalcium silicate (C3S) particles, which is the main component of cement before hydration, eliminate the crystal nucleus of hydrated calcium silicate on the surface of the particles, and prevent the formation of hydrated calcium silicate, that is, the formation of cement body.
Examples:
On the London Underground Victoria Line in January 2014, when the builder was filling an elevator shaft with cement, the cement was accidentally leaking into the control room on the side. As a result, the subway control room was flooded with concrete, making it impossible for passengers to go out by subway. In the control room of the Victoria Line of the London Underground, which was flooded with concrete, the concrete that would harden in just a few hours was about to cover the important cables and control switches, and then stiffened step by step. if you don't stop it, the whole control room will be buried and will never be used again. At this time, the maintenance workers rushed into the surrounding convenience store, bought bags of white material, and then poured it into the unhardened cement and stirred it continuously to ease the hardening speed of the cement. Yes, this white substance is sugar.
Benefits of Sugar as Retarder:
Although there are commercial retarders on the market, the price of white sugar is relatively low. And only a small amount of sugar can significantly alleviate the stiffness time of cement. For example, adding 0.04% sugar can double the setting time of cement that can be hardened in an hour and 18 minutes.
In addition, during the construction of the project, spray sugar water on the uncondensed cement surface, and then wash the surface off, exposing the gravel below, which can also create a rough matte effect of the vicissitudes of life.
Principle of Using Sugar as a Retarder:
The more common Portland cement is mainly composed of limestone, clay, gypsum and sand. After adding water, the concrete will have hydration reaction, and finally produce hydrated calcium silicate (C-S-H).
Sugar can absorb tricalcium silicate (C3S) particles, which is the main component of cement before hydration, eliminate the crystal nucleus of hydrated calcium silicate on the surface of the particles, and stop the production of hydrated calcium silicate, that is, the cement body.
Note:
Using sugar as retarder is only suitable for more convenient retarding methods in ordinary construction, but not suitable for projects with higher difficulty and higher requirements, such as oil well cement retarder or high temperature retarder.
Concrete Additives Supplier
TRUNNANO is a reliable concrete additives supplier with over 12-year experience in nano-building energy conservation and nanotechnology development.
If you are looking for high-quality concrete additives, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com)
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Concrete additive is a chemical substance added in the process of mixing concrete, accounting for less than 5% of the quality of cement, which can significantly improve the performance of concrete. Concrete additive is characterized by many varieties and a small amount of additives, which has a great influence on the performance of concrete. Concrete additives have become an important component of concrete.
Classification of Concrete Additives:
1. Early strength agent:
A. soluble inorganic salts: chloride, carbonate, nitrate, thiosulfate, silicate, aluminate, alkaline hydroxide, etc.
B. soluble organic matter: triethanolamine, calcium formate, calcium acetate, calcium propionate and calcium butyrate, urea, oxalic acid, amine and formaldehyde condensate.
2. Accelerator: iron salt, fluoride, aluminum chloride, sodium aluminate, potassium carbonate.
3. Air entraining agents: Wood resin salts, synthetic detergents, lignosulfonates, protein salts, fatty acids and resin acids and their salts.
4. Water reducers and coagulants: lignosulfonates and their modifiers or derivatives, hydroxy carboxylic acids and their salts or their modifications and derivatives, inorganic salts (zinc salts, borates, phosphates, chlorides), ammonium salts and their derivatives, carbohydrates and polysaccharides or sugar acids, water-soluble polymers (cellulose ethers, melamine derivatives, naphthalene derivatives, polysiloxanes and sulfonated hydrocarbons).
5. Superplasticizer: naphthalene sulfonate formaldehyde condensate, polycyclic aromatic hydrocarbon sulfonate formaldehyde condensation, melamine sulfonate formaldehyde condensation polymer, p-aminobenzenesulfonate formaldehyde condensation polymer, sulfonated ketone aldehyde condensation polymer, polyacrylate and its graft copolymer, etc.
6. Retarders: polymers containing carboxyl, phosphonic and sulfonic groups, and organic retarders such as hydroxycarboxylic acid (salt) and organic phosphonic acid (salt).
7. Aerating agents: hydrogen peroxide, metal aluminum powder, some activated carbon adsorbing air.
8. Expansion agent: fine iron powder or granular iron powder and oxidation accelerator, lime system, sulphoaluminate system.
9. Binder: synthetic latex, natural rubber latex.
10. Pumping agents: viscosity of synthetic or natural water-soluble polymer additives, organic flocculants, inorganic materials with high specific surface (bentonite, silica, asbestos powder, asbestos staple fiber, etc.), cement admixtures (fly ash, hydraulic lime, stone powder, etc.).
11. Flocculant: polymer electrolyte.
12. Colorants: grey to black (iron oxide black, mineral black, carbon black, group cyan, phthalein blue), light red to dark red (iron oxide red), brown (iron oxide brown, manganese-rich brown soil, burning cinnamon soil), green (chromium oxide green, phthalein), white (titanium dioxide), etc.
13. Fungicides and pesticides: polyhalides, dieldrin emulsions and copper compounds.
14. Moistureproof agents: soap, butyl stearic acid, some petroleum products.
15. Impervious agent: water reducer, calcium chloride.
16. Alkali aggregate reaction inhibitors: lithium salt, barium salt, some air entraining agents, water reducer, retarder, pozzolanic.
17. Rust inhibitors: sodium nitrite, sodium benzoate, calcium lignosulfonate, phosphate, sodium fluorosilicate, sodium fluoroaluminate.
18. Grouting admixture: retarder, gel, gel starch and methylcellulose, bentonite, thickener, early strength agent, aerator.
Concrete Additives Supplier
TRUNNANO is a reliable concrete additives supplier with over 12-year experience in nano-building energy conservation and nanotechnology development.
If you are looking for high-quality concrete additives, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com)
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What is polycarboxylate superplasticizer?
Polycarboxylate superplasticizer is an important additive to ensure the strength of concrete and achieve pumping performance, and plays a pivotal role in improving and improving the operability of concrete construction. In this paper, according to the action mechanism and influencing factors of concrete water reducing agent in concrete construction, the optimal dosage of concrete water reducing agent is accurately determined, the dosage method of water reducing agent is found, and the compatibility and compatibility of water reducing agent with cement are verified. Adaptability, simply, accurately and reliably guarantee the quality of the project, reduce the cost of the project, and achieve the best effect of the construction project.
Why should polycarboxylate superplasticizer be added to concrete?
After the cement is mixed with water, many floc structures will be formed due to the gravitational effect between the cement particles, so that 10% to 30% of the water is wrapped in them, which greatly reduces the fluidity of the concrete mixture. When an appropriate amount of water-reducing agent is added, the molecules of the water-reducing agent are directionally adsorbed on the surface of the cement particles, and the hydrophilic group of the water-reducing agent points to the aqueous solution. And it increases with the increase of the concentration of the superplasticizer, resulting in electrostatic repulsion, which causes the cement particles to disperse each other, the flocculation structure disintegrates, the number of capillary pores is significantly reduced, and the mixing water wrapped in it is released, which can effectively increase the concrete mixing. fluidity and compactness.
After adding an appropriate amount of water-reducing agent to concrete, it can reduce the water-cement ratio of concrete, reduce the amount of cement, improve the early strength of concrete, advance concrete formwork removal time, accelerate formwork turnover, shorten construction period and reduce project cost.
There is a compatibility problem between superplasticizer and each component material of concrete, which has the greatest impact on cement, between the same cement and different superplasticizers, or between the same superplasticizer and different cements. There is a significant difference in the compatibility of concrete, and this difference will affect the rheological properties of concrete, thereby affecting the workability, strength and durability of concrete. Therefore, it is necessary to do a series of comparative tests for the selection of various types of concrete water reducers, as well as the performance and dosage of water reducers to determine the optimal dosage of concrete water reducers.
TRUNNANO is a concrete additives supplier with over 12 years experience in nano-building energy conservation and nanotechnology development. We accept payment via Credit Card, T/T, West Union and Paypal. Trunnano will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.
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Concrete is the main raw material of modern construction engineering, and it is welcomed because of its high strength and long service life. In the process of concrete mixing, adding appropriate amount of admixture can improve the performance and quality of concrete.
Concrete Additives
In general, the substances added to concrete to improve the performance of concrete in the mixing process and before mixing are called admixtures. In general, the quality of the admixture mixed into concrete shall not be greater than 5% of the cement quality.
Retarder, accelerator and early strength agent can adjust the hardening property and setting time of concrete.
The main function of admixtures such as air entraining agent, water reducer and pumping agent is to improve the rheological properties of concrete mixture and make it easier to be pumped to the designated location.
Admixtures such as waterproofing agent, air entraining agent and rust inhibitor are used to improve the durability of concrete.
In order to improve the other properties of concrete, admixtures such as colorant, aerating agent, antifreeze and expansive agent need to be mixed into concrete.
Influence of Superplasticizer
It would affect the collapse degree of concrete.
In general, a certain amount of superplasticizer is added to concrete to achieve the purpose of increasing the collapse of concrete, which can effectively improve the workability of newly mixed concrete.
Experience shows that the collapse of concrete without superplasticizer within 1 hour is less than that of concrete without superplasticizer. The main reason for this phenomenon is that concrete still needs to go through the processes of mixing, transportation and pouring after adding superplasticizer. Therefore, it is necessary to use the method of adding water to restore the collapse of concrete mixed with superplasticizer in the concrete construction site, but this method will significantly reduce the performance such as coagulation strength, which may lead to concrete cracking, abnormal hardening and other phenomena.
In order to effectively solve the problem of collapse loss of concrete mixed with superplasticizer, it is suggested that the method of adding superplasticizer in batches and post-admixture should be adopted. The batch mixing method can not only effectively avoid the loss of concrete collapse, but also control the production cost to a certain extent and realize the benefit of concrete construction.
Function of Antifreeze and Early Strength Agent
Antifreeze is a kind of admixture which can prevent the moisture in the material from freezing at low temperature. for example, when the project is below zero in winter, it can make the concrete work normally at low temperature.
Early strength agent refers to the admixture which can improve the early strength of concrete and has no significant effect on the later strength.
When the anti-freezing agent is constructed in winter, when the concrete strength reaches a certain limit value, because the structure has been initially formed and has the ability to resist frost heave damage, the concrete will not be frozen even if it is frozen again, which is called the anti-freezing critical strength of concrete.
Concrete early strength agent refers to the admixture which can improve the early strength of concrete and has no significant effect on the later strength. The main function of early strength agent is to accelerate the hydration rate of cement and improve the early strength of concrete.
Antifreeze is that when the temperature of the concrete project is zero or below zero in winter, it can make the concrete work normally at low temperature.
The early strength agent does not contain chloride ion and has no rust effect on steel bar, so it is suitable for all civil, industrial buildings and prestressed reinforced concrete members, mortar and so on. It is most suitable for construction at low temperature in early winter and early spring. When used in Portland cement, it plays a particularly significant role in strengthening and modifying slag cement.
Concrete Additives Supplier
TRUNNANO is a reliable concrete additives supplier with over 12-year experience in nano-building energy conservation and nanotechnology development.
If you are looking for high-quality concrete additives, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com)
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