What is the difference between polycarboxylate water-reducing agent and naphthalene-based water-reducing agent?
Different water reducing rates
The water-reducing rate of polycarboxylic acid-based water-reducing agents is significantly higher than that of naphthalene-based water-reducing agents. Under the condition of exceeding the same water-reducing rate, the dosage of polycarboxylic acid-based water-reducing agents may be smaller than that of naphthalene-based water-reducing agents; in addition, as the dosage increases, the ultimate water-reducing rate of polycarboxylate water-reducing agents far exceeds that of naphthalene-based water-reducing agents, while the dosage of naphthalene-based water-reducing agents exceeds the limit when the dosage is around 2.0%, which shows that polycarboxylate water-reducing agents are more suitable, it is more suitable to make low water-cement ratio high-strength concrete.
Different mechanisms of action
The mechanism of action of polycarboxylate water-reducing agent is mainly based on steric repulsion. In addition to steric repulsion, it also has a strong air-entraining isolation "ball" effect and the effect of reducing solid-liquid interface energy; the naphthalene series water-reducing agent has The mechanism of action is mainly electrostatic repulsion, and there are almost no other beneficial effects on water reduction.
• rom the perspective of usability, polycarboxylate superplasticizer has strong plasticity retention and can effectively control the loss of slump over time without having much impact on the hardening time of concrete. It has a large reinforcing effect and has shrinkage resistance, which can more effectively improve the impermeability and frost resistance of concrete, and can improve the durability of concrete to a greater extent than naphthalene-based water reducing agents.
