Poly (carboxylic acid high efficiency water reducing agent is a kind of high performance products, often and concrete collocation is used, but some people have no contact with this product, in the process of using will enter use erroneous zone, such as water reducing agent with other varieties, to join the common poor stability of the performance of the modified component or product problems, these problems are relatively easy to enter the erroneous zone, here we explain for everybody the three myths that you later at the time of use can be avoided, here we together and see it!
1, with other varieties of water reducing agent used, no superposition effect
In the past, when concrete was prepared, the variety of pumping agent could be changed at will, and there would not be a great difference between the characteristics of concrete mixture and the laboratory results, and there would not be a sudden change in the characteristics of concrete mixture.
But since the mixing station preparation according to the needs of user after blending poly carboxylic acid series of concrete water reducing agent, will often appear some very confusing problem: equipment in the performance of concrete mixture gravely deviates from the advance of experimental results, sometimes water content has a big, concrete is still very dry, sometimes the slump loss of concrete mixture faster than adding regular pumping agent, sometimes concrete mixture could not discharge, and the intensity of concrete sample measured specimen, it is too low to more believe!
We all know that the traditional superplasticizer, such as lignosulfonate superplasticizer, naphthalene superplasticizer, melamine superplasticizer, aliphatic superplasticizer and sulfonate superplasticizer, can be mixed in any proportion to meet the special preparation requirements of different projects, or get better economy.
These superplasticizer compound use can obtain the superposition (in most cases better than single mixing) use effect, and the solution of these superplasticizer can be mutually soluble (in addition to lignosulfonate superplasticizer and naphthalene series superplasticizer mutually soluble to produce part of the precipitation but does not affect the use effect).
But polycarboxylic acid system superplasticizer and other varieties of superplasticizer compound use, but not easy to superimpose the effect, and polycarboxylic acid system superplasticizer solution and other varieties of superplasticizer solution of mutual solubility itself is very poor.
2. There is no modification effect after adding commonly used modified components
Now for poly (carboxylic acid high efficiency water reducing agent 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.
Due to the diversity and instability of cement, admixture and aggregate in engineering, it is very important for the additive supplier to make compound modification of polycarboxylic acid superplasticizer according to the engineering needs.
At present, the compound modification technology of superplasticizer is basically based on the modification of traditional superplasticizer such as lignosulfonate system and naphthalene system.
The experimental results show that the previous modification techniques are not necessarily suitable for polycarboxylic acid superplasticizer.
For example, sodium citrate is not suitable for polycarboxylic acid superplasticizer in the modified retarder component of naphthalene superplasticizer. It not only does not play a retarder effect, but may promote coagulation, and the mutual solubility of sodium citrate solution and polycarboxylic acid superplasticizer is also poor.
Moreover, many varieties of defoaming agent, air entrain agent and thickening agent are not suitable for polycarboxylic acid system water reducer.
Based on the above test and analysis, we see not hard, because of the particularity of poly carboxylic acid is a molecular structure of water reducing agent, is the present stage of research depth and application experience, through other chemical composition on modification of poly (carboxylic acid is water reducing agent means not much, but in the past for other varieties water reducing agent modified by established theory and standard specification, for poly (carboxylic acid is water reducing agent, may need deeper exploration research on modification and supplement.
3. The performance stability of the product is too poor
Concrete water-reducing agent synthesis enterprises can be considered as fine chemical enterprises are not many, many enterprises only stay in the primary production stage of mixing machine and packaging machine, product quality is limited by the quality of master material.
In terms of production control, the instability of raw material source and quality has always been a major factor affecting the performance of polycarboxylic acid superplasticizer.
As is known to all, one of the raw materials of naphthalene series high efficient water reducing agent several degrees of industrial naphthalene, the supply and demand contradictions tension naphthalene series high efficient water reducing agent product price and product quality fluctuate, the production control of ready-mixed concrete companies and had a significant impact on the quality of concrete engineering, but the quality fluctuation most of naphthalene series high efficient water reducing agent also just in plasticizing effect and strengthening effect.
Department of poly carboxylic acid water reducing agent products from the beginning of the main raw materials imported from Germany, South Korea, to now are all made of domestic raw materials, the product performance and quality has been very big fluctuation, this not only in terms of plasticizing effect, and meantime, bubble structure, retarding effect, slump retention and viscosity, etc.
In order to increase profits, individual production units change the solid content of masterbatch or the mixing amount of main components at will, which leads to the fish-eye mixing of polycarboxylic acid water reducer market, which makes it difficult to guard against.
