The performance advantages of polycarboxylate water reducers are mainly reflected in: low dosage (0.15% to 0.25% (reduced solid content), high water reduction rate (generally 25% to 35%), good slump retention, low shrinkage , It has a certain amount of air entrainment, and the total alkali content is extremely low.
However, in practical use, polycarboxylic acid water-reducing agents will also encounter some problems, such as:
1.The water-reducing effect is highly dependent on the concrete raw materials and mix ratio, and is greatly affected by the sand content and the quality of mineral admixtures. ;
2. The effect of water reduction and slump retention depends greatly on the amount of water reducing agent, and it is difficult to maintain slump with low content;
3. The use of high-concentration or high-strength concrete has a large amount of concrete and is sensitive to water consumption. Fluctuations in water consumption may lead to great changes in slump; 4. Compatibility problems with other types of water-reducing agents and other admixtures, or even no superimposing effect;
5. Sometimes concrete bleeding is large, air-entraining is serious, and air bubbles Large and many;
6. Sometimes temperature changes will affect the effect of polycarboxylic acid water-reducing agent.
