11, Apr 2022
As widely known, high strength cement paste, mortar and concrete, can be obtained by the incorporation of a well–designed combination of cement, filler, and superplasticizer (SP) . Quite often, SNF is applied as good filler, due to its high surface area and is a very reactive pozzolana because of its highly amorphous silica and its ability to react with free calcium hydroxide (CH), to the form hydrosilicates.
Cement containing SF exhibits higher strength than non–blended materials, therefore it is used to manufacture high-strength concrete . Moreover, SF acts not only as filler or pozzolanic material, but also to improve the cement paste–aggregate interface, which contributes to further improving concrete strength. Incorporation of SF, also affects fresh cement flowability, however, substantially raising the water demand, and its high early age hydration reactivity increases the heat of hydration and consequently intensifies total shrinkage.
Superplasticizers are frequently used in concrete technology for three different purposes or a combination of these: – to increase the workability without changing the mix composition to enhance placing characteristics of concrete, – to reduce the required water of standard consistency in order to increase the strength of concrete , – to reduce both water and cement at a given workability in order to save cement and reduce creep, shrinkage and thermal strains caused by heat of cement hydration . The fresh characteristics of concrete made with Portland cement (PC) can be modifified and controlled with superplasticizers. Achieving the steepest decline in the water–cement ratio, greatest workability and decreasing the viscosity is, however, contingent upon the compatibility between the admixture chosen and the cement. The presence of flfly ash (FA) and SF may positively affect the interaction between SP and cement components
Superplasticizers improve the rheological performance of cement paste, due to the dispersion of agglomerated cement and hydrating particles.Such agglomerates formed during the initial mixing of OPC with water; result from relatively large Van der Waals attractive forces, which operate at inter–particle distances in the range of 5 to 7 nm. Loosely entrapped quantities of water are associated with the agglomerated network of particles.
Anionic polymers, such as SNF or SMF have the ability to overcome the Van der Waals forces by imparting a stronger repulsive force at the surface–liquid interface, freeing the entrapped water. The dispersing effect of superplasticizer was ascribed to the development of the electrostatic (negative) charge on the cement particles .
11, Apr 2022
Naphthalene Sulfonate Formaldehyde (SNF) polycondensate is a linear polymer, while Polycarboxylate Ether (PCE) has comb copolymers with an adsorbing backbone and nonadsorbing side chains. Both of them are known to adsorb on cement particles or agglomerates, thus dispersing both cement particles/agglomerates and increasing flowability.
It has a powerful dispersing action on a concrete. The use of SNF Usual is based on its ability to reduces the water/cement ratio, to form flowing concrete and consequently increases the strength of the hardened material.
SNF disperses cement particles and reduces attractive interparticle forces, such as van der Waals forces, by electrostatic repulsion, while PCE acts through both electrostatic repulsion and steric hindrance between nonadsorbing side chains .
SNF seems to be more robust in Self-Consolidating Concrete (SCC). To fulfill other rheological properties, such as high stability, low segregation, Viscosity Enhancing Admixtures (VEA) or Viscosity Modification Agents (VMA) are also commonly added in SCC.
Superplast Usual has to be disolved first (if it was in powder form). Ready to be used liquid is added into a concrete and a mortar in the amount 0.3 – 0.8 % of dry substance from cement mass.
30, Mar 2022
Sulfonated naphthalene formaldehyde (SNF) introduce
SNF’s full name is Sodium Naphthalene Sulfonate Formaldehyde Condensate. It also called Sodium Naphthalene sulfonate Formaldehyde, Sodium Naphthalene Formaldehyde, Sulfonated Naphthalene Formaldehyde, Naphthalene Sulfonate Formaldehyde Condensate, NSF, FDN,PNS. Also you can get its information by searching SNF chemical.
Sulfonated naphthalene formaldehyde (SNF) is a major ingredient of superplasticizers used for the purpose of water reducing agent in the concrete admixtures, it promotes dispersing of cement particles and reduce water requirements without affecting the workability, thus resulting high-strength concrete and lower permeability.
Its high purity makes cement particles with high dispersancy, low foaming, high range water reducing and obvious strengthening so that we can accelerate project mould turnover and construction speed, and save cement, and also improve cement mobility and workability. SNF is a high range concrete admixture of concrete cast-in-place, prefabricating, pump and curing.
Technical features & adaptability
1. Mixing amount: 0. 5-1. 0% of cementing materials, reducing rate: 20-30%
2. Keeping concrete strength intact & mixing this product, cement saving amount can reach 15-20%
3. Mixing this product 0. 7% (solid content) , slump constant increases above 10cm
4. Adapting to high strength, early strength, flowing, prefabricating & curing and prestressing force concretes etc.
5. The agent can be combined with other externally applied agents if pilot devement or laboratory experiment succeeds.
SULPHONATED NAPHTHALENE FORMALDEHYDE (SNF) has a good adaptability to various cements and it is not erodent to reinforcing bar and nonpoisonous and pollution-free. SULPHONATED NAPHTHALENE FORMALDEHYDE (SNF) has been applied to the highway, bridge, tunnel, water conservancy hydroelectric project, port, quay, skyscraper, power engineering, industrial civil building, prestressing force component and high range concrete etc.
Construction industry: High Range water reducer in concrete. Water reduction in concrete up to 25%. Higher slump with lower water – cement ratio. Flow able & pump able concrete with improved theology. Possess homogeneous, free from Honeycombing and dense concrete. High strength due to reduced water – cement ratio.
- It is an aqueous solution of Sulphonated Naphthalene Formaldehyde, Sodium salt polymer.
- This is an excellent dispersing agent.
- Designed to offer wider tolerances in formulations for concrete admixture manufacturers.
- It is compatible with most of the additives used in admixture formulations.
- It helps in producing concrete with various unique properties.
30, Mar 2022
Citric acid is one of the most common food preservatives and flavoring additives. It can be found naturally in citrus fruits but is also manufactured. Its name is derived from the fact that it’s an organic acid found in many fruits and vegetables, especially citrus fruits. Citric acid is a concentrated powder that is prized for its sour flavor, preservative quality, and ability to act as a pH buffer. For these reasons, citric acid is found on the ingredients list of many foods in your kitchen pantry, including preserves, candy, and crunchy snacks. It is also known as “sour salt” due to its flavor and similar appearance and texture to salt.
- Also Known As: Sour salt
- Shelf Life: 3 years opened; 5 years unopened
- Used As: Flavor enhancer and preservative
- Taste: Sour
What Is Citric Acid?
In 1917, American food chemist James Currie discovered that the mold Aspergillus niger could produce citric acid as a byproduct of metabolizing sucrose or glucose, which has proved more efficient and less expensive than extracting from citrus fruits. Although citric acid is found in high concentrations in many citrus fruits like lemons, it is not economical to extract the acid from fruit for industrial use. Plus, the demand for citric acid far outweighs the supply of citrus fruit available. Thus, once it was possible to produce a seemingly endless supply of citric acid, companies like Pfizer and Citrique Belge began manufacturing it on an industrial scale.
Citric Acid Uses
Citric acid has many uses in food production. It is a flavor enhancer, preservative, and helps facilitate the ripening process. About 50 percent of the world’s citric acid production is used as a flavor booster in beverages, and because citric acid is made in a powder form, it’s added to dry foods such as seasoning salts, flavoring powders, and crunchy snacks when a sour flavor is desired.
The acidic pH of citric acid makes it useful as a food preservative and preserves the color of the food since it significantly slows the oxidation. Since many bacteria are unable to grow in an acidic environment, citric acid is often added to jams, jellies, candy, canned foods, and even meat products as a form of preservation. Citric acid is also used to facilitate the ripening process when making cheese, particularly mozzarella. It is employed to adjust the pH of solutions when brewing both beer and wine, and works to keep fats from separating in homemade ice cream; it also prevents sugar from crystallizing in caramels. A small pinch of citric acid can also enhance the leavening power of baking soda, making it an ideal secret ingredient for cakes and biscuits. Those on a low-sodium diet may sub in citric acid for salt when seasoning.
How to Cook With Citric Acid
Citric acid can be measured and added to recipes either as an ingredient or as a replacement for other acids like lemon juice or vinegar. For example, when canning tomatoes, a 1/2 teaspoon of powdered citric acid can be used for every quart of tomatoes. The citric acid powder can also be sprinkled over finished recipes such as guacamole or raw fruit such as apples, to maintain color.
If making cheese like ricotta or paneer, citric acid will guarantee a perfect balance of acidity without adding any additional flavors. Dissolve a 1/2 teaspoon citric acid in 2 tablespoons of water and use in place of 2 tablespoons lemon juice or vinegar.
Citric acid can be used in place of salt in sour bread recipes like sourdough and rye. Most often, no more than 1 tablespoon of citric acid will be needed. It can also be used when preparing game meat to help eliminate any bacteria: Spray a solution of 1 ounce citric acid with 1 quart water prior to cooking.
Be mindful that the acid is an irritant to the eyes as well as the skin with prolonged exposure, so take caution when using.
What Does It Taste Like?
Citric acid adds a sour taste to dishes and has a slightly tart, refreshing flavor, which balances the sweetness in sodas, teas, juices, and other drinks.
Citric Acid Recipes
Unless making your own cheese, it may be hard to come by a variety of recipes calling for citric acid. But those that include vinegar or lemon juice on the ingredient list—like certain soups and pickled foods—are good candidates for using the sour powdered substance.
- Make Your Own Paneer
- How to Can Tomatoes (in place of lemon juice)
- Copycat Chipotle Guacamole (sprinkle over to keep green)
Where to Buy Citric Acid
Citric acid can be bought in powder form and is usually available in stores with other home canning supplies, as well as in natural food stores or health food stores along with other vitamins and dietary supplements. In some grocery stores, citric acid is sold in small shakers and labeled as “sour salt.” It is also often found at Indian food markets as it is used to make paneer. Citric acid is packaged in pouches, tubs, and canisters, and is available in bulk.
Store citric acid in its original container in a cool, dry place. From the date of manufacturing, it has a shelf life of three years once opened and will stay stable for at least five years unopened.