Sodium naphthalenesulfonate is mainly used in the construction industry. It is available in the form of light brown powder that reduces cement dosage. Hence, if you want to improve the workability and strength of your concrete, you need to add SNF powder to it. Here are a few reasons to use sodium naphthalene sulfonate in concrete.
Why Should You Use Sodium Naphthalene Sulfonate?
Sodium naphthalene sulfonate in concrete is primarily used as a water reducer. The height of the slump affects the consistency and fluidity of the concrete. This, in turn, affects the flow and workability of the concrete.
According to concrete experts, the wetter the concrete mix, the higher the slump. So, in order to achieve a higher slump, you would have to add more water. However, the concrete consistency and strength are affected if there is too much water in the mixture.
Sodium naphthalene sulfonate (SNF) works in two ways to improve concrete strength. First, it helps in reducing water content in the slump while also increasing the volume.
Adding sodium naphthalene sulfonate can maintain the water-cement ratio constant and still get a 10 cm increase in the slump. In addition, the water-reducing rate of SNF can reach 15-25% helping one achieve greater concrete strength.
For best results, you need to add SNF in the ratio of 0.5％~1％ of the weight of the concrete slurry. The strength of the concrete also depends on the quality of Sodium naphthalenesulfonate.
When you go to buy SNF powder, you need to purchase a good quality product. The sodium naphthalene sulfonate price is directly related to the chemical composition and quality of the product. Before knowing the factors that determine the sodium naphthalene sulfonate quality, here are the different types of Sulfonates:
Type of Sulfonates
There are three types of SNF products available in the market. The physical and chemical composition of the products vary.
SNF-A - It is available in the form of yellow-brown powder. The PH value of SNF-A is between 7.0-9.0. The chlorine content in SNF-A is around 0.3% max, while Na2SO4 Content is 5% max.
SNF-B - It has similar physical properties to SNF-A (yellow-brown powder). The difference lies in their chemical composition. The PH value of SNF B also lies between 7.0 and 9.0. The main difference between SNF-A and SNF-B is the higher chlorine content which is around. 0.4% max. SNF-B also has higher Na2SO4 Content that stands at 10% max.
SNF-C – It looks similar to SNF-A and SNF-B; it is available in the form of yellow-brown powder. The PH value is in the range of 7.0 and 9.0. The chlorine content in SNF-C is around 0.5% max, while Na2SO4 content is 18% max.
Though the physical properties of SNF-A, SNF-B, and SNF-C are the same, the sodium naphthalene sulfonate price of all three types differ due to varying chemical compositions.
The net starch fluidity is an essential factor in determining the quality of sodium naphthalene sulfonate. In addition, the starch in SNF positively influences several properties of concrete like the heat of hydration, compressive strength, and creep. The SNF-A has the highest net starch fluidity that stands at 250mm.
SNF-B and SNF-C have 240 and 230 mm net starch fluidity. As per concrete experts, a typical concrete structure would benefit from the performance of SNF-A due to its high fluidity. The use of SNF-A in the concrete would be more affordable and cost-efficient than using self-compacting concrete.
Water Reducing Rate
The primary purpose of adding sodium naphthalenesulfonate to the concrete is to reduce the need for water in the mixture. By reducing the amount of water in the concrete, builders can achieve a higher density cement paste that also enhances the quality of the cement paste. The SNF-A has the highest water reducing rate in all three, standing at a rate of 26%.
On the other hand, the SNF-B and SNF-C have a water reducing rate of 25% and 23%, respectively. So it's obvious sodium naphthalenesulfonate with the highest water reducing rate will be a better quality product for the construction industry, and hence the more expensive option.
NA2SO4 Concentration – The standard curing environment in the construction industry uses different concentrations of NA2SO4.. The NA2SO4 solution is known to suppress the cement’s hydration rate. As the NA2SO4 concentration in the sodium naphthalenesulfonate increases, the dynamic elastic nature and compressive strength of concrete decreases.
The highest quality sodium naphthalene sulfonate will have a lower NA2SO4 concentration. For example, SNF-A has the lowest NA2SO4 concentration that stands at less than or equal to 5%. On the other hand, SNF-C has the highest NA2SO4 concentration at 18%, while in SNF-B, NA2SO4 concentration is around 10%.
To sum up, sodium naphthalene sulfonate is a valuable chemical compound for the construction industry. It reduces the water requirements and also strengthens the concrete. However, you need to be careful and select the best quality sodium naphthalene sulfonate as per project needs.