The setting of cement is impeded by lignosulfonates. This retardation can sometimes be beneficial, but only under certain conditions .Sugars make up approximately 25% of spent liquor. This can have a significant retarding effect. It is desirable to remove all or some of the sugars. To reduce the sugar content of the spent sulfite alcohol, there are several methods available such as ultrafiltration, alkaline heat treatments, or precipitation. The retarding effect is reduced by purification. It does not disappear, however, as sugar-free lignosulfonate shows a retarding effect. The lignosulfonates that are commercially available cause retardation. This can be sometimes, but not always, increased by retardation from residual sucroses.
Lignosulfonates can be purchased as calcium, magnesium, and sodium salts. For formulations that contain other polymers, sodium salts will be preferred. Calcium could cause precipitation of calcium with sulfate-ions that may also be present in other formulation components, e.g. poly naphthalene (PNS), or polymelamine (PMS) would cause precipitation of gypsum with sulfate ions that may be present in other formulation constituents, e.g. Lignosulfonates can be purchased as either a brown, aromatic-smelling powder or brown 30-40% solutions.
Their molecular weight is another important factor that affects the performance of lignosulfonates. Studies with lignosulfonates of different molecular masses have shown better plasticizing results (Reknes & Gustafsson 2000). While lignosulfonate is most commonly used for the formulation and use of water-reducing materials, it is rarely or never used in high-performance concrete design. It is believed that lignosulfonates of higher molecular mass, in which sugars and other lower molecular-weight compounds are removed, can be used to reduce water loss up to 20% with moderate retardation
The superplasticizer and retarding agent in construction is lignosulfonate cement retarder. Concrete can be improved by concrete’s absorption or dispersion. This compound is reusable and can be used as an early strength agent, antifreeze, or pumping agent, as well as a naphthalene Superplasticizer compound that contains liquid admixtures with virtually no precipitate.
The Lignosulfonate superplasticizer dosage for cement content 0.20 to0.30% is commonly used at 0.25% water reduction up to 9-11%. The appropriate dosage will result in a significant increase in strength. Strength for 7 days increased by 15-20%, strength for 28 days increased by 20-30%, and strength for long-term increased by 15-20%.
Concrete can be used as-is without changing the water content ( suggested ratio 0.65)1to improve concrete flow and workability.
Concrete slumps can be maintained at the same intensity as reference concrete. Cement can be saved between 8-10% and 30-40 tons by using a one-ton Lignosulfonate super plasticizer.
Concrete mixed with this agent can delay concrete in its standard state compared to the reference concrete setting times of concrete for more than 3 hours. Concrete set time of 3 hours is favorable to summer construction, commodity concrete transport, and mass concrete.
Micro-entraining with Lignosulfonate super plasticizer can increase concrete freeze-thaw performance.
Increase its water dispersion capacity to avoid water bubbles inside the slump.
It is suitable for concrete, concrete products, concrete construction in summer, and pumping concrete.
The recommended dosage is 0.25-0.50% based on cement weight, with a maximum of 0.25%.
You can add the powder to cement, sand, and gravel. However, you should stir the mixture for a longer time to prevent uneven mixing. You can prepare powder in advance by adding a small amount of the solution in liquid form to the concrete. However, this should not be considered in the calculation of concrete water consumption.
When using this product, users should ensure that it is used according to their specific construction conditions (construction season and construction materials, etc.). Refer to the concrete mix description to ensure that you get the best results.