1. The water reduction rate fluctuates from high to low. In the publicity materials of polycarboxylic acid series water reducing agent which is difficult to control in the project, the water reduction effect is often specially publicized, such as the water reduction rate up to 35% or even 40%.
2. The water-reducing effect of polycarboxylic acid series water-reducing agent depends heavily on its content. In general, as the amount of water-reducing agent increases, the water-reducing rate increases.But after a certain amount of doping, it even appears that with the increase of mixing amount, the effect of reducing water "decreases".
3. The concrete prepared by polycarboxylate superplasticizer is bleeding seriously, and the indicators that reflect the performance of concrete mixture are usually fluidity, cohesiveness and water retention.Concrete prepared with polycarboxylic acid superplasticizer does not always meet the requirements of use.Therefore, in the actual test at present, we usually use terms such as severely exposed rock stacking, severe bleeding segregation and bottom slicing to vividly describe the performance of concrete mixture.
4, large liquidity concrete easily layered segregation in most cases, using poly (carboxylic acid is the big liquidity concrete water reducing agent, even if the dosage of water reducing agent, water control are yes, concrete mixture is not bleeding, but it is very easy to appear statified, segregation phenomenon, the performance of the concrete is coarse aggregate sinking, mortar or net pulp to rise.
5. When preparing concrete in the past, the variety of pumping agent can be changed at will, and there will be no great difference between the properties of concrete mixture and laboratory results, and no mutation in the properties of concrete mixture.
6 and join the common without modification effect after the modification components for poly (carboxylic acid fasten jianshuiji research spending less, in most cases, the goal of scientific research is to further improve the plastic is minimised only water effect, it's hard to do according to different engineering needs, through the molecular structure design synthesis with different retarding effect of coagulation, gas, or different gas, different viscosity of poly (carboxylic acid water reducing agent series products.
7, the performance stability of the product is too poor concrete water-reducing agent synthesis enterprises can be counted as fine chemical enterprises, many enterprises only stay in the primary production stage of mixing machine and packaging machine, product quality is limited by the quality of the base material.In terms of production control, the instability of raw material source and quality has been a major factor affecting the performance of polycarboxylate superplasticizer.
