What is the compounding method of polycarboxylic acid water reducer?

Commonly used composite materials include sodium gluconate, dextrin, air entraining agent, defoamer, sodium nitrate, inorganic salt, ethanolamine reinforcing agent and so on.

The compounding method is as follows:

Compounded with traditional water reducer.

The molecular structure of polycarboxylate superplasticizer is artificially designed, which is mostly "comb" or "dendritic", and its molecular main chain is connected with several branches with certain length and stiffness. Sulfonates or other groups in the main chain can charge cement particles. Once the main chain is adsorbed on the surface of cement particles, the branched chain will form a three-dimensional intersection with the branched chains on the surface of other particles, preventing the particles from approaching each other, thus achieving the function of dispersion (that is, reducing water).

The molecules of traditional water reducer (lignosulfonate, naphthalene sulfonic acid condensate, sulfonated melamine, etc. ) are all linear structures. Once molecules are adsorbed on the surface of cement particles, molecular sulfonate groups charge the surface of cement particles to form an electric field. Because the charged particles are mutually exclusive, the particles are dispersed in the medium (water), thus achieving the effect of reducing water. The molecular weight varies greatly with the proportion of effective components. If * * * is used together, it will produce adverse reactions, resulting in the irreconcilability of concrete.

Compound with retarder:

Because of the large slump loss of naphthalene superplasticizer, compound retarder was often used to solve this problem in the past. There are many kinds of retarders, which have different adaptability with polycarboxylate superplasticizer.

Among them, sodium citrate is not suitable for compounding with polycarboxylic acid water reducer. When it is compounded with polycarboxylic acid water reducer, it can't slow setting, but it may cause rapid setting, and the mutual solubility of sodium citrate solution and polycarboxylic acid water reducer is also poor.

The retarder mainly made of sodium gluconate is a retarding modified component of naphthalene-based water reducer, which has good operability and retarding effect when compounded with polycarboxylic acid-based water reducer. In the case of appropriate dosage, it can also improve the strength of concrete.

Polycarboxylic acid water reducer:

Polycarboxylic acid water reducer is a kind of high-performance water reducer and also a cement dispersant used in cement concrete. Widely used in highways, bridges, dams, tunnels, high-rise buildings and other projects. This product is environmentally friendly, non-flammable and non-explosive, and can be safely transported by train and car.

Polycarboxylic acid water reducer is a high-performance water reducer and a cement dispersant for cement concrete. Chemically, it can be divided into two types: methacrylic acid as the main chain, carboxylic acid group as the side chain, MPEG (methoxypolyethylene glycol) and polyester structure.

Historically, before the appearance of polycarboxylic acid additives, there were lignosulfonate additives, naphthalene sulfonate formaldehyde condensate, melamine formaldehyde condensate, acetone sulfonate formaldehyde condensate, sulfamate formaldehyde condensate and so on. These products have certain advantages in cost, have certain adaptability to sandstone and other materials with high mud content, have a large market share, and have different degrees of application in concrete engineering.