Use polycarboxylate superplasticizer
1. What is polycarboxylate superplasticizer
polycarboxylate superplasticizer is a kind of unsaturated monomer containing carboxyl group, copolymerized with unsaturated monomer containing other functional groups, which can make concrete have excellent performance in water reduction, collapse protection, environmental protection, etc. High polymer. The advantages of polycarboxylic acid high-performance water-reducing agent, such as low dosage, high water-reducing rate, controllable chemicalbook sub-structure, good dispersibility, green environmental protection, and strong adaptability, have attracted the attention and research of a large number of scholars and experts. It is widely used in engineering construction in various fields, which has become the future development trend of concrete admixtures. The research of polycarboxylate high-performance water-reducing agent is an inevitable requirement in the concrete field.
2. Why we use polycarboxylate superplasticizer?
- polycarboxylate superplasticizer has good compatibility with various cements, and the slump retention performance of concrete is good, which prolongs the construction time of concrete.
- Low dosage, high water reduction rate and small shrinkage.
- Significantly improve the early and late strength of concrete.
- Polycarboxylate superplasticizer has low chloride ion content and low alkali content, which is conducive to the durability of concrete.
- The production process of polycarboxylate superplasticizer is pollution-free and does not contain formaldehyde. It conforms to the ISO14000 environmental protection management international standard and is a green and environmentally friendly product.
- Using polycarboxylate superplasticizer, more slag or fly ash can be used to replace cement, thereby reducing costs. The scope of application of polycarboxylic acid water reducer is suitable for precast and cast-in-place concrete, reinforced concrete and prestressed concrete for high-speed railways, passenger dedicated lines, industrial and civil buildings, roads, bridges, ports, airports and other engineering constructions.
3. How’s the market for polycarboxylate superplasticizer?
About half of the world’s cement is consumed in China, and China is undoubtedly the world’s concrete production and application center. Almost all of the world’s polycarboxylate superplasticizer manufacturers gather in China to promote new products and technologies. Obviously, my country is becoming a center for the promotion and application of polycarboxylate superplasticizer water-reducing agents. At the same time, it predicts that it will become a research center in the near future. A favorable environment.
At present, many domestic enterprises that have completed industrialized production, even including many foreign-funded enterprises whose products have entered the Chinese market, still belong to the chemical industry. They are very familiar with the research and development of such products, synthetic production and other technologies, but For the concrete construction and application technology, it is slightly insufficient, which is not good for the expansion and application of this type of product in my country.
Therefore, it is necessary to strengthen the application technology research of such At present, polycarboxylate superplasticizer are mainly applied to special concretes such as high-strength concrete and self-compacting concrete, which to a certain extent also affects the promotion and application of such products in a wider range of concrete engineering.
products and the popularization of concrete engineering application knowledge, and strengthen the technical cooperation between chemical synthesis engineers and concrete materials engineers.
As a water-reducing agent with excellent comprehensive performance, polycarboxylate superplasticizer has a lower dosage and a higher water-reducing rate, and the mixed concrete has good slump retention performance. polycarboxylate superplasticizer has more advantages than traditional naphthalene and aliphatic water reducers when mixing high-strength concrete. Since polycarboxylate superplasticizer has a higher water reducing rate, even if the dosage is reduced when formulating medium and low strength concrete, it is possible to obtain a higher water reducing rate than naphthalene-based and aliphatic water reducing agent.
The high water reduction rate of polycarboxylate superplasticizer reduces the water consumption of concrete, and the total slurry of concrete is reduced when the water-to-binder ratio remains unchanged, which affects the working performance of concrete. Therefore, when using polycarboxylate superplasticizer to prepare low-strength grade concrete, its dosage must be strictly controlled. When preparing low-strength grade concrete, a phenomenon will be found: when the amount of water reducing agent is slightly too large, the concrete mixture will have bleeding, segregation and other poor workability.
If the admixture is too small, the concrete mixture is likely to have insufficient fluidity and poor slump retention effect, which makes it difficult to meet the construction requirements. In addition, due to the poor quality of sand and gravel used in low-strength grade concrete, the amount of polycarboxylate superplasticizer increased, and the cost-effectiveness was reduced.
In order to better use polycarboxylate superplasticizer in low-strength concrete, the author believes that the following points should be noted for your reference
The higher the solid content of the polycarboxylate superplasticizer, the lower the content of the polycarboxylate superplasticizer to achieve the same water-reducing rate. When formulating low- and medium-strength grade concrete, if a polycarboxylate superplasticizer with a higher solid content is used, the water reduction rate is too high and the water consumption is reduced.
Once the water consumption increases, concrete bleeding will occur. When formulating low- and medium-strength grade concrete, the required water reduction rate is low.
The use of high solid content polycarboxylate superplasticizer will often result in too low admixture content. The lower the water-reducing agent consumption, the lower the water-reducing agent consumption And the more sensitive the water consumption, the less convenient the production control.
For example, if the amount of polycarboxylate superplasticizer fluctuates by 0.5kg/m3 or the water consumption fluctuates by 5kg/m3, the concrete mixture will undergo major changes, sometimes even segregation, bleeding, hardening, and even blockage during construction. Pipe, sometimes the concrete mixture becomes unable to meet the workability required by the construction.
Therefore, when using polycarboxylate superplasticizer to produce low- and medium-strength grade concrete, it is advisable to control the solid content of polycarboxylate superplasticizer at 8%-10% (when the mixing amount is 1.8%, the water-reducing rate is controlled at 20% Below) to facilitate concrete production control.
The low solid content polycarboxylic acid reduces the sensitivity of the amount of water reducing agent and water consumption. In the concrete production process, even if the water content of sand and gravel fluctuates, it can effectively control the workability of concrete to produce greater fluctuations.