At present, foreign polycarboxylic acid admixtures are still mainly polyester type. The major development of polycarboxylate water reducers in Japan in recent years is to force the use of all admixtures and concrete shrinkage reducers. The Japan Society of Civil Engineers has proposed new specifications. Each grade of concrete presents an indicator for controlling concrete shrinkage.
The development trend of polycarboxylic acid products is low dosage, high efficiency and multi-functionality. It can adapt to cement and admixtures with many varying components, and can resist the adsorption of excessive sulfate in high mud content sand and cement.
Previously used chain transfer agent thioglycolic acid, due to easy polymerization during storage, according to authoritative data, 3 months polymerizable failure 10%, so the market began to turn to mercaptopropionic acid, this chain transfer agent can be relatively stable for a long time, 3 months from The polymerization is only about 1%.
Compared with thioglycolic acid, there is a clear advantage in the application of 3-mercaptopropionic acid, which is why 3-mercaptopropionic acid is currently widely used by polycarboxylate additive manufacturers.