Sodium naphthalene sulfonate formaldehyde (SNF), also named poly naphthalene sulfonate (PNS) or sulphonated naphthalene formaldehyde, is light brown powder in appearance. As a commonly used high-efficiency water reducing agent for concrete, Its main chemical component is naphthalene sulfonate formaldehyde condensate. Sodium naphthalene has the characteristics of high water reduction rate, small impact on the setting time of concrete, and low air entrainment. Therefore, SNF is widely used in highways, bridges, dams, docks, tunnels, water conservancy and industrial and civil construction projects, steam curing and natural curing, prefabricated components, etc.
Naphthalene superplasticizer is the main raw material for various compound admixtures, such as pumping agent, retarding superplasticizer, early-strength superplasticizer, etc. It can be used for concrete construction where the daily minimum temperature is above 0℃, and can also be used to prepare high-fluidity concrete, high-strength concrete and steam-cured concrete.
| Type | SNF-A | SNF-B | SNF-C |
|---|---|---|---|
| Solid Content (%) ≥ | 92% | ||
| PH Value | 7-9 | ||
| Na2SO4 Content (%)≤ | 5 | 10 | 18 |
| Chlorine Content (%)≤ | 0.3 | 0.4 | 0.5 |
| Net Starch Fluidity(mm)≥ | 250 | 240 | 230 |
| Water Reducing Rate(%) | 26 | 25 | 23 |
| Packing | 25kg pp bag; 650kg Jumbo bag. A customized package is available. | ||
Main Performance Characteristics of Sodium Naphthalene Sulfonate
High water reduction rate. In most cases, the water reduction rate of SNF can reach more than 25%. It can effectively increase the fluidity of concrete, reduce bleeding and segregation, thereby improving the workability of concrete, making it easier to construct and compact.
Enhancement. Naphthalene series superplasticizer can significantly improve the strength and durability of concrete, especially for high-strength concrete and prestressed concrete.
Adaptable. It can be adapted to various specifications and models of cement. It has good compatibility with other admixtures, and can be matched with admixtures such as expansion agents, air-entraining agents, and active admixtures such as fly ash to complement and stimulate each other.
The setting time is appropriate. This product has little effect on the initial and final setting time of cement, and the difference in setting time is generally within 1 hour.
Low sodium sulfate content. In winter, SNF does not crystallize after being formulated into a liquid, thereby solving the problem of pipe blockage caused by sodium sulfate crystallization in winter concrete manufacturing, and greatly facilitating winter concrete construction.
Good durability. SNF can effectively improve the pore structure of concrete, thereby greatly improving the durability performance indicators of concrete such as impermeability, carbonation resistance, and freeze-thaw resistance.
Easy to use. SNF powder can be used directly, or it can be dissolved in water first and used as a solution-type admixture. It is suitable for various construction environments or mixer types.
The application scope of SNF superplasticizer is centered around their core advantages:
The high water reduction rates for high-strength, pumping-based projects; compatibility with additives for harsh environments and tight deadlines; and balanced cost-effectiveness for general construction projects. From super-high-rise core structures to ordinary municipal roads, from precast component factories to post-disaster reconstruction sites, SNF water reducers are the preferred option for any project requiring concrete strength ≥C30 and fluidity sufficient for pumping or complex pouring.
Especially in high-strength concrete projects with C40-C80 strength, its comprehensive performance and economic advantages are irreplaceable, making it a key admixture for concrete engineering, characterized by its strong adaptability and high practical value.
The key to using SNF sodium naphthalene sulfonate lies in “precise control” and “advance trial mixing.” The dosage must be adjusted according to cement type, ambient temperature, and construction requirements. Small-batch trial mixes should be conducted to verify fluidity, setting time, and strength. Furthermore, standardized storage and construction operations are crucial to fully utilize its high water reduction rate and avoid problems such as segregation and strength fluctuation. Especially in high-strength, high-flow concrete projects, the SNF usage precautions must be integrated with project specifics to ensure performance meets standards and construction safety.
(1) The recommended dosage range is 0.5%-1.5% of the cement content (solids content). The specific dosage should be adjusted based on the specific application. High-strength concrete (C60-C80) can be controlled at 1.0%-1.5%, while standard pumpable concrete (C40-C50) should ideally be 0.7%-1.0%. Its use in low-strength concrete (C30 and below) is not recommended due to the high water reduction rate, which can lead to segregation.
(2) Cement Compatibility: Suitable cements include ordinary Portland cement (P·O 42.5 and above) and high-grade slag Portland cement (P·S 52.5). These cements have a low C3A content (≤8%) and react stably with SNF.
(3) Concrete admixtures that can be mixed include early strength accelerators (calcium chloride, sodium sulfate) and air-entraining agents (sodium dodecylbenzene sulfonate). The mixing ratio should be determined through trial mixing. For example, a 5:1 mixing ratio of SNF to sodium sulfate can increase the three-day strength of concrete by 15%-20%.
(4) The Admixtures that cannot be mixed include retarders (such as sodium gluconate) and expansive agents (such as UEA). SNF already has a certain retarding effect, and mixing it with retarders will result in a prolonged setting time. Mixing it with expansive agents may also cause a chemical reaction, reducing the expansive effect.