Polycarboxylate Superplasticizer(PCE) is an important component of grouting mortars. It is an admixture that can significantly reduce the water content of grouting mortars. The content of polycarboxylate superplasticizer can change the fluidity and improve workability. Due to the reduction of water & cement ratio, the strength and durability of grouting mortars, and other properties are improved.

The functions of adding polycarboxylate superplasticizer to grouting mortars are as following:

1. Dispersion effect:
After cement mixed with water, the cement slurry forms a flocculation structure, due to the molecular gravity of the cement particles, so that 10% to 30% of the mixing water is wrapped in cement particles and cannot participate in free flow and lubrication, thus affecting the flowability of concrete mix. When polycarboxylate superplasticizer is added, polycarboxylate superplasticizer molecules can be directionally adsorbed on the surface of cement particles, forming electrostatic repulsion, which causes the cement particles to disperse with each other, destroy the flocculation structure, and release the wrapped parts,  which increasing the fluidity of concrete admixture.
 

2. Lubricating effect:
Polycarboxylate Superplasticizer with high hydrophilic, on the surface of cement particles can form a stable solvated water film with water molecules. This water film has a good lubrication effect, and can effectively reduce the sliding resistance between particles and  improve the fluidity of concrete.

3. Sustained release effect:
During the preparation process of polycarboxylate superplasticizer, some branched chains are grafted on the molecules. This branched chain not only provides steric hindrance effect, but also acts as a barrier in the high alkalinity environment of cement hydration. The branch chains can be slowly cut off, releasing polycarboxylic acids with dispersing effects, which can improve the dispersion effect of cement particles and control slump loss.
 

4. Steric hindrance:
The hydrophilic polyether side chains in superplasticizer structure extend in the aqueous solution, forming a hydrophilic three-dimensional adsorption layer with a certain thickness on the surface. When cement particles are close to each other, the adsorption layers begin to overlap, steric hindrance occurs between the cement particles. The more overlap, the greater steric repulsion, and the greater the obstruction to the cohesion between cement particles, causing the concrete with good slump.