How to determine the optimum dosage of concrete superplasticizer
The US President recently said the conflict between Russia and Ukraine had driven up the prices of all the world's major food staples, including wheat, corn, barley, oilseeds and edible oils, and that Russia and Ukraine together supplied more than 25% of the world's wheat exports and about 20% of its barley exports.
To address the food shortage, the Biden administration says it plans to increase the number of counties eligible for insurance for double cropping. Double cropping is when farmers grow two different crops a year on the same field.
Under Biden's plan, the number of counties eligible for two-season crop insurance would increase by 681, for a total of 1,935.
The UN has warned that up to 1.7bn people are "highly exposed" to the domino effect of the conflict between Russia and Ukraine on the global food, energy, and financial systems. The agency says conflict could increase hunger in countries where people are already suffering from malnutrition.
Even countries where food is less scarce are being hit by rising prices. U.S. grocery prices rose 1% in April, compared with a 10.8% increase over the past 12 months, the Labor Department said recently.
According to the White House, global food prices have risen nearly 13 percent since the outbreak of the Russia-Ukraine conflict.
Besides, affected by the ever-changing international situation, the supply and prices of international bulk concrete superplasticizer are still very uncertain.
Determination of the optimum dosage of concrete superplasticizer by the fluidity of cement paste
In terms of the adaptability of cement and concrete superplasticizer, the type and quality of concrete superplasticizer also play an important role. Therefore, concrete superplasticizers should be selected according to the adaptability to cement and construction requirements. When the high-efficiency concrete superplasticizer is incompatible with a certain cement, the following situations will occur:
1. Concrete is abnormally coagulated during the mixing process.
2. The slump loss of mixed concrete is large.
3. Concrete bleeding and delamination are serious.
4. The high-efficiency concrete superplasticizer has insufficient water-reducing effect or no water-reducing effect at all.
5. The strength of concrete does not increase significantly at each age, or even decreases.
6. The shrinkage rate of concrete increases more, resulting in cracking.
These incompatibility phenomena mentioned above should be avoided as much as possible when selecting a concrete superplasticizer.
The amount of concrete concrete superplasticizer is not only related to the amount of cement, but also has a great relationship with the physical properties and chemical composition of cement.
The traditional method for determining the amount of concrete superplasticizer in concrete is mainly determined according to the product specification of concrete superplasticizer and the percentage of cement consumption. Due to the difference in chemical composition and content of different varieties or batches of cement, the compatibility and adaptability of concrete superplasticizers and cement and the optimal dosage will also be quite different. It is difficult to ensure the best water-reducing effect of the mixture by only determining the amount of concrete superplasticizer based on the percentage of cement consumption, and it is easy to cause waste of concrete superplasticizer. Luoyang Tongrun has used the method of cement slurry fluidity to determine the optimum amount of concrete concrete superplasticizer after many tests, and achieved good results. The specific method is to accurately weigh the high-efficiency water-reducing agent, water and 300g cement according to the dosage recommended by the manufacturer's instructions, and mix the high-efficiency water-reducing agent, water and cement paste according to the standard method. On the clean glass, put the mixed cement paste into the test mold, and after lifting the test mold one by one, observe the flow of the cement paste, and test whether the fluidity of the cement paste can meet the performance requirements of concrete pumping. At the same time, record the size and dosage of water reducing rate of different cements and different concrete concrete superplasticizers for optimization.
The order of adding concrete superplasticizers. Multiple comparison tests of different concrete superplasticizers show that the mixing sequence of concrete superplasticizers has a certain influence on the water-reducing effect of concrete superplasticizers. Take the high-efficiency water-reducing agent produced by Longda as an example: after weighing a certain amount of cement, high-efficiency water-reducing agent and water, pour cement → high-efficiency water-reducing agent → water into the mixing pot in sequence, and measure the cement paste. Expansion is 22cm ~ 23cm. According to the order of adding cement → water first, after stirring for a certain period of time, adding concrete superplasticizer, the measured expansion degree of cement paste is 25cm ~ 27cm. It can be seen that using the same cement and the same concrete superplasticizer, the post-blending method is better than the first-blending method, which is beneficial to improve the compatibility of the concrete superplasticizer and the cement, and give full play to the efficiency of the concrete superplasticizer. In the same way, in the actual construction of concrete, the concrete superplasticizer should be added after the concrete mixture is stirred for a certain period of time to achieve the best effect of water reduction.
Luoyang Trunnano Tech Co., Ltd (TRUNNANO) is a professional concrete superplasticizer powder supplier with over 12 years experience in chemical products research and development. We accept payment via Credit Card, T/T, West Union and Paypal. Trunnano will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.
If you are looking for high quality concrete superplasticizer, please feel free to contact us and send an inquiry.
The concrete superplasticizer industry has experienced demand expectations driven by the rise and the off-season tired stock driven by the seasonal decline in two rounds of the market. Affected by the COVID-19 epidemic and other factors, inventories of manufacturers continue to accumulate, putting pressure on market sentiment. In addition to off-season factors, the weak trend of concrete superplasticizer also reflects the market's concern about the epidemic and some other related enterprises' financial situation.