From concrete to mortar, why add polycarboxylate superplasticizer


Release time:

2016-05-11

Author:

New Earth Group

Source:

From concrete to mortar, why add polycarboxylate superplasticizer

    Polycarboxylate superplasticizerIt is a kind of superplasticizer used in building materials. For mineral binder (ordinary cement, calcium chlorate cement, calcium sulfate), the anti-flocculation ability of the product is stronger than that of the traditional water reducing agent, and the effect is more durable. In recent years, polycarboxylic acid water reducing agent to replace the traditional water reducing agent gradually dominate, and from the main concrete application to a variety of mortar applications, so why more and more concrete, mortar products are adding polycarboxylic acid water reducing agent, the following describes the advantages of polycarboxylic acid water reducing agent:
1. After the cement is mixed with water, due to the molecular gravity of the cement particles, the cement slurry forms a flocculation structure, so that 10% to 30% of the mixing water is wrapped in the cement particles, which cannot participate in free flow and lubrication, thus affecting the fluidity of the mixture. When the water reducing agent is added, the water reducing agent molecules can be adsorbed on the surface of the cement particles, so that the surface of the cement particles with the same charge (usually negative charge), the formation of electrostatic repulsion, promote the mutual dispersion of cement particles, flocculation structure destruction, release part of the wrapped water, participate in the flow, thus effectively increasing the fluidity of the mixture.
2. The hydrophilic base in the water reducing agent is very polar, so the water reducing agent adsorption film on the surface of cement particles can form a stable solvated water film with water molecules. This water film has a good lubricating effect and can effectively reduce the sliding resistance between cement particles, thus further improving the fluidity.
3, steric hindrance: water-reducing agent structure with hydrophilic polyether side chain, stretching in the aqueous solution, so as to form a certain thickness of the hydrophilic solid adsorption layer on the surface of the adsorbed cement particles. When the cement particles are close to each other, the adsorption layer begins to overlap, that is, the steric hindrance effect is generated between the cement particles. The more overlap, the greater the steric repulsion, the greater the obstacle to the cohesion between the cement particles, so that the slump of the concrete remains good.
4. In the process of preparation, some branched chains are grafted onto the molecules of the water reducing agent, which can not only provide steric hindrance effect, but also can be slowly cut off in the high alkalinity environment of cement hydration, thus releasing polycarboxylic acids with fractional action, thus improving the dispersion effect of cement particles and controlling slump loss.
shandong new earth industrial group co., ltd. specializes in providing polycarboxylate superplasticizer powder and liquid polycarboxylate superplasticizer, pay attention to us-learn more about mortar additive products.
聚羧酸减水剂

Key words:

Polycarboxylate superplasticizer