In many concrete projects, traditional high-efficiency concrete such as naphthalene is less and less able to meet engineering needs due to the limitations of technical performance. A new generation of water reducing agent and polycarboxylate high performance water reducing agent that has attracted much attention at home and abroad. Because it has designed an effective molecular structure based on the mechanism of dispersed cement, it has a super-dispersion type and can prevent concrete slump loss. It does not cause obvious retardation, exerts high plasticizing effect under low dosage, has good fluidity retention, has large freedom of cement to adapt to wide molecular structure, has a large amount of synthetic technology, and has high room for high performance. The effect is remarkable, which can reduce the shrinkage of concrete and the technical properties of extremely low harmful substances, which gives the concrete excellent workability, good strength development, excellent durability, and good performance of polycarboxylate high-performance water reducer. Comprehensive technical performance advantages and environmental protection features meet the needs of modern concrete engineering. Therefore, polycarboxylate superplasticizers are becoming the preferred admixture for the preparation of high performance concrete.
(1) Reasonable control of water consumption
Polycarboxylate superplasticizers are very sensitive to water consumption, especially when using a higher solids water reducing agent. During the trial and production process, it was found that sometimes the water consumption increased slightly by 1kg to 3kg, and the concrete mixture showed serious bleeding, dew piles, and segregation. Therefore, on the one hand, the water consumption of the single side is strictly controlled on the one hand, and the water content of the sand and gravel is accurately measured. The newly washed sand should be put on hold for a period of time, and then used when the water content is relatively stable. On the other hand, a low solids polycarboxylate superplasticizer is used to reduce sensitivity.
(2) use a reasonable amount of polycarboxylic acid
During the use process, the appropriate dosage is determined through experiments. When the dosage is low, the concrete has poor sealing ability, the slump loss is fast, the fluidity is deteriorated, and when the dosage is too large, the concrete mixture is likely to cause serious bleeding and segregation. Grab the bottom. Before production, the best combination of concrete water consumption and polycarboxylate water reducer dosage should be tested, that is, the optimal water consumption and admixture dosage, while paying attention to the fluctuation of raw material to polycarboxylate superplasticizer. The impact of quantity. The raw materials used in the project should be used during the test to facilitate production control. If necessary, the on-site construction conditions should be simulated according to the construction requirements.
(3) dare to break the traditional thinking mode
In the preparation of high-strength grades, efforts to overcome the use of cement-less mineral admixtures, think that this is safe, the strength will be higher, in fact, the cement is often used to thicken the concrete, the early strength of the concrete develops fast, the growth is slow or not growing in the later period. . Sometimes adding 30kg of cement and concrete without adding cement is about the same, sometimes it is better not to add. Appropriate increase in the amount of mineral admixture will increase the strength of concrete by 5% to 10%, and the strength growth in the later stage is also satisfactory, and it is helpful to reduce hydration heat, prevent cracks, and improve durability.
(4) It is strictly forbidden to mix naphthalene admixtures
Companies that use both naphthalene-based water reducers and polycarboxylate water reducers should, if possible, use sub-station. If the same unit has both polycarboxylic acid and naphthalene, it must be used interchangeably. The admixture weighing container, pipe and mixer are thoroughly cleaned, and the concrete tank car is also cleaned and refilled. It is strictly forbidden to mix naphthalene water reducer and polycarboxylate water reducer. Especially at the construction site, when the method of “second addition of admixture” is needed to adjust the workability of concrete mix, it is necessary to clarify the concrete inside the car. The type of admixture used avoids the “quick setting” of the concrete caused by the mixing, which causes the concrete of the vehicle to be scrapped.
(5) Strengthen inspection
When the polycarboxylate water reducing agent is purchased, first check various technical indicators of the water reducing agent to ensure the stability of the quality. Secondly, the raw materials used should be selected, and the mixing ratio of the production should be used for testing. If problems are found, the technicians of the admixture production enterprises should be adjusted in time.
(6) Communicate with the construction unit in time
Before the concrete production, the technical requirements of the concrete and the transportation distance, construction technology, temperature of the day, etc. should be known to the construction party. If necessary, go to the working surface for on-site inspection to understand whether the concrete pumping method, the pipeline layout path are reasonable, and the distribution of the steel bars. , the staffing of the construction unit, the quality of the team, etc., according to the actual situation, rational allocation and reasonable dispatch of transport vehicles.
(7) Familiar with the characteristics of the polycarboxylate superplasticizer used
Through experiments, the variation rules of polycarboxylate superplasticizer in the trial-construction-production-construction of concrete are summarized, which is convenient for dealing with emergencies. Exploring these laws in the test and production practice, accumulating experience, and when a sudden change in the concrete state occurs, timely propose a reasonable solution to avoid causing greater losses and achieve “timely, scientific and reasonable”.
Concrete additives for concrete are like salt for a dish. A dish is inseparable from salt, and concrete is inseparable from concrete additives.Its amount is very small compared to the total amount of concrete, but it is indeed essential.
Concrete Superplasticizers of Dongke Brand mainly divided into two categories: mother liquor and powder. The solid content of the mother liquor is generally about 50%, and the solid content of the powder is generally about 97%. The amount of our products is very small, the dosage of the mother liquor is generally 0.3-0.4%, and the dosage of the powder is generally 0.16-0.2%.
Send your inquiry / assessment to Us. Anything need us ,please don’t hesitate contact us here! we will keep it secret for you !