(1) The adaptability of polycarboxylic superplasticizer liquids is directly related to its dosage.
As we all know, the high-grade concrete with higher content of naphthalene water reducer has better fluidity and less slump loss, but the medium-low-grade concrete often has poor fluidity and larger slump loss, and the most effective measure to improve its adaptability is to increase the content appropriately. The same is true for liquid admixtures of polycarboxylic superplasticizers. C30 concrete is prepared with commonly used cementitious materials and aggregates in Beijing and polycarboxylic superplasticizers are used as admixtures. The results show that when the amount of superplasticizer is between 0.13% and 0.15%, concrete can obtain better fluidity, but slump loss is widespread. Larger, no matter what kind of common retarder is compounded and how much dosage is added, when the dosage of superplasticizer reaches 0.16%, most concrete can maintain good fluidity after one hour.
(2) Cement with poor adaptability to naphthalene-based superplasticizers generally has poor adaptability to polycarboxylic acid-based superplasticizers.
Generally speaking, cement with high alkali content, high aluminate content or high fineness needs a lot of water. Naphthalene superplasticizer has higher content and larger slump loss. Similarly, polycarboxylic acid superplasticizer has the same rule. Some cement mixed with naphthalene water reducer has lagging bleeding phenomenon, but the polycarboxylic acid superplasticizer liquids will also bleed, but to a lesser extent. If there is abnormal slump loss of cement due to gypsum (concrete loses fluidity after several minutes of starting), the polycarboxylic acid superplasticizer liquid will not be improved. It can only be fundamentally solved by adding sulfate ions at the same time, which is consistent with naphthalene superplasticizer.