The application of biological methods in concrete water-reducing agents at home and abroad is mainly divided into the application of biological methods in polyether macromonomers, the application of biological methods in water-reducing agents, and the application of biological methods in the compounding of water-reducing agents. , hoping that through sharing, it can bring more inspiration and promotion to the application of biological methods in water-reducing agents.
Petroleum resources are a scarce and difficult-to-renew resource. Extensive development and utilization will also cause atmospheric and other types of environmental pollution and ecological damage. In addition, the current trade war initiated by the United States has a huge impact on oil prices in the international market and my country's oil imports. With the country's increased investment in people's infrastructure welfare and stimulating domestic demand, the concrete water-reducing agent industry has huge development potential.
However, at the same time, the ZTE incident also warned an enterprise of the importance of independent innovation and intellectual property rights. Therefore, for the concrete water-reducing agent industry, it is necessary to accelerate industrial upgrading and transformation, develop green and clean new energy, and control enterprise production costs. It is particularly important to enhance the core competitiveness of enterprises. The mainstream concrete water-reducing agent on the market, polycarboxylate water-reducing agent, mainly adopts the synthesis method of copolymerizing polyether macromonomer, acrylic acid and other auxiliary materials to obtain a semi-finished product, and then compounding the water-reducing agent (mainly adjusting the retardation time) The finished product is directly applied to the concrete.
1. Application of biological method in polyether macromonomer - Biomethod EO
Polyether macromonomer is the most important raw material in the upstream of polycarboxylate water-reducing agent. At present, The large monomers TPEG and HPEG used in the market and the newly developed EPEG and VPEG are all produced by ring-opening polymerization of different initiators and EO (ethylene oxide). The main substance EO is mainly produced through naphtha in the traditional way. The other method is to produce ethylene from oil and then oxidize ethylene. The other method is the MTO method, which is mainly through the process of coal-to-methanol and then oxidized ethylene. The biological method to produce EO mainly starts from biomass (mainly using renewable corn ethanol, straw ethanol or The process of producing ethanol first and then ethylene and then oxidation (using cassava ethanol as raw materials), domestic process patents mainly include SD and SHELL, which are characterized by green and environmentally friendly products, low energy consumption, and zero emissions. Its shortcomings are due to the state’s strict control over domestic The stable control of the grain market and the overall high price of ethanol have resulted in the high cost of polyether macromonomers produced by manufacturers. They need to survive well when EO prices are high.
2. The application of biological methods in concrete water-reducing agents
The application of biological methods in concrete water-reducing agents was first reflected in 1935 when Acrituret and others in the United States successfully developed a wood-based water-reducing agent. After a long period of development, biological methods have been widely used in concrete water-reducing agents with sulfonate as the main component.
2.1 Starch-based water-reducing agent
The patent for starch-based water-reducing agent was first proposed by Kolainan et al. in 1970. Cheng Fa et al., Zhang D F et al., Wang Tiantang et al., Ma Jianyan et al., Lu Shenghua et al. et al., Wu Jiayao et al., Zhang Yanfei et al. modified starch materials with different components through molecular chain degradation, oxidation, esterification, etherification, graft modification, and composite modification to obtain concrete water-reducing agents.
2.2 Other-based water-reducing agents
Wang Lijiu et al., Maimaiti et al., Rouzi et al., Huang et al., Mishra et al. modified cellulose and waste and obtained certain reductions. Water reducing agent with high water rate and retarding effect. In addition to cellulose, starch and their degradation derivatives modified as water-reducing agents, concrete water-reducing agents have also been developed using raw materials such as chitosan and leaves.
2.3 Polycarboxylate water-reducing agent
Wang Hailin used maleic anhydride and glucolactone to synthesize glucolactone maleate, and Wang Wenping used sucrose ester, sorbitol, and citric acid. modified polycarboxylic acid water-reducing agent, Fu Xinjian et al. used hydroxypropyl cellulose-modified polycarboxylic acid water-reducing agent, Chen Yan et al. developed a new type of sucrose-based polycarboxylic acid high-performance water-reducing agent, which mainly combines naturally occurring Renewable resources are grafted onto the cosmetic polycarboxylate water-reducing agent through esterification and other forms. Natural biological resources are abundant and low-priced. On the one hand, the cost is reduced, and on the other hand, the performance is often better than that of pure biological water-reducing agents. Much better.
3. The application of biological methods in the compounding of water-reducing agents
The compounding of water-reducing agents is mainly to enhance the adaptability of the masterbatch to raw materials, adapt to customer needs for the masterbatch, and Adjust the retarding time, etc. Among them, the adjustment of the retarding time is particularly important.
Sodium gluconate has become the mainstream retarder on the market due to its outstanding retarding effect, good solubility and low price. Sodium gluconate is particularly famous for its biological fermentation method. This method has the characteristics of fast fermentation speed, easy control of the fermentation process, and easy extraction of the product. However, it also has certain defects, such as the difficulty in controlling the color of the product and high sterility requirements.
Every year, a large amount of juice waste liquid is processed everywhere. Chen Tao and others use expired juice waste liquid as a retarder in concrete. It has excellent performance in the retarding effect, condition and appearance of concrete. Waste recycling is environmentally friendly and cheap, and the mixed juice has a better retarding effect.
3 Conclusion
At present, most biological methods in concrete water-reducing admixtures still remain in the laboratory. This is mainly due to the complex production process, high cost, and natural polymer-based raw materials. The structure is often complex and changeable, and production stability control is also a problem. At high temperatures, attention must be paid to anti-corrosion work. So how to simplify the process, reduce costs, improve performance, and stabilize...Issues such as production and anti-corrosion require more scientific research practitioners to continue to work hard to develop and explore.
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