Superplasticizers, commonly considered effective water reducers, are among the most valuable knowledge in the construction industry as they help improve the quality of construction work.
Superplasticizers are specifically used to produce high-quality concrete with high strength and high performance.
Increases the plasticity or viscosity of a material.
It is often used to reduce the water content and improve the workability of concrete.
Reducing the water-cement ratio increases the strength of concrete.
Superplasticizers are very sensitive to concrete additives compared to other previously used additives. Compatibility issues may arise, especially with different cement properties and additive dosages, and we may have to compromise on benefits.
Superplasticizers are organic polyelectrolytes that belong to polymeric dispersants. Some of the superplasticizers are synthetic, while others are derived from natural products.
Superplasticizers are basically divided into four types.
- Sulfonated formaldehyde melamine condensate (SMF)
- Sulfonated Naphthalene Formaldehyde Condensate (SN F)
- Modified lignosulfonates and others such as
- Sulfonic acid esters and carbohydrate esters
The development of superplasticizers began more than three decades ago.
The main disadvantage of using these materials is the loss of slump.
Especially in hot environments, the advantage of using superplasticizer is nullified due to the above problem. However, the new generation superplasticizer with superior performance is able to maintain consistency.
There are different factors that affect additive performance .
They can essentially be identified as follows.
- Additive type and dosage
- Nature of cement and aggregates
- Water-cement ratio
- Environmental conditions
- Additive addition process.
Furthermore, there are problems that lead to incompatibility between cement and additives. The following causes can be identified as main aspects:
- Type and dosage of additives
- Cement texture
- Type of aggregate
- Water-cement ratio
- Environmental conditions
- Additive addition process
The following problems may occur due to Incompatibility problem between cement and additives
- Rapid loss of workability
- demarcation
- Setup acceleration/delay
- Little increase in strength
- Air inclusion
Furthermore, it is known that the understanding of the interaction between cement/additive and additive/additive is still pending.
Furthermore, studies on this topic need to be carried out.
Poor integration of additives/additives has caused critical problems and it is a known fact that some of the additives cannot be mixed with other additives according to the manufacturer's information.
Most often, these are changes to product specifications.
The creation method of some interaction problems can be summarized as follows
- Individual additives exhibit different behaviors and differ significantly from each other, although they are all considered superplasticizers from the same chemical family.
- Due to the low water-cement values and the high dosage of additives, deviations occur more frequently in concrete.
- Choosing the right flow and dosage type (optimal strength or dosage range) can help reduce compatibility issues
There are different methods available to find the right combination of cement and superplasticizer.
The results of the Marsh Cone test and viscometry study could be used for evaluation.
A comparison of flow time with mini-slump propagation and rheological parameters, the influence of cement type on the interaction between cement and superplasticizer, the effect of temperature on superplasticizer-cement paste fluidity, the influence of temperature on cement integration -superplasticizer, the influence of cement fineness on the polycarboxylate ether paste and the influence of cement fineness on the interaction between cement and superplasticizer could also be considered for evaluation.
In summary, the following can be said: Main problems with excessive dosage f.
- An overdose can lead to a large drop loss. Therefore, the optimal dosage should be used, which was briefly described above.
- In general, the strength of concrete increases as the dosage of superplasticizer increases. However, above a certain value (at higher dosages), the strength of the concrete decreases significantly. The final strength may even be lower than that of the control mixture.
- Adding too much superplasticizer disrupts the hydration process because additional additions add more water to the concrete.
- An overdose also leads to an acceleration of the deflocculation of cement particles. Furthermore, as the dosage increases, water retention increases and hydrated cement is formed.
- Furthermore, excessive dosage results in bleeding and segregation. Affects the cohesion and conformity of the concrete. Furthermore, it reduces the compressive strength of concrete.
The concrete article Additives More information about additives can be found at. Other classifications, Wikipedia For more comprehensive knowledge on this topic, you can also refer to the article.
