A brief comparison of PCE superplasticizer & SNF water reducing agent

SNF water reducer

PCE superplasticizer plays an important role in high-performance concrete. With the development of concrete technology, more and more attention is paid to the durability of concrete. As the durability increases, the water-binder ratio of concrete often needs to be reduced, but the fluidity of concrete still needs to meet the requirements of pumping construction. In addition to the high water-reducing effect, the water-reducing agent also needs to be able to control the slump loss of concrete, and the ordinary high-range water reducing agent often fails to meet the requirements.

SNF(Naphthalene based) water reducing agent is commonly referred to β-Naphthalene Sulphonate Formaldehyde Condensate (short name: SNF, PNS, NSF, etc…). It is the largest and most widely used water reducing agent in China currently(≥ 70%). It is characterized by high water reducing rate (15% - 25%), no air entrainment, little influence on setting time, relatively good adaptability with cement, composite use with other additives and relatively low price. SNF is widely used to prepare high fluidity, high strength and high performance concrete. The slump loss of concrete with simple addition of SNF is faster. In addition, the adaptability of SNF to some cement needs to be improved.

As a new generation of high-performance superplasticizer, the PCE has a comb-shaped molecular structure, it is featured as good adaptability with cement, low dosage, high water reducing rate, good slump resistance of the prepared concrete, good workability etc. Moreover, it overcome the shortcomings of SNF with formaldehyde in the production, especially suitable for the production of high performance concrete, has been widely researched and developed rapidly in recent years. While from the perspective of the variety and market share of PCE on the market currently, the application and promotion of PCE is still in its early stages, and it has promising application prospects.

PCE Powder
PCE superplasticizer
PCE Powder
PCE powder

  In the experimental comparison of PCE superplasticizer and SNF water reducing agent, the performance characteristics of them are studied as below:

(1) The water-reducing rate of PCE is significantly higher than that of SNF water-reducing agent. When the same water-reducing rate is achieved, the dosage of PCE is much lower than that of SNF water-reducing agent.

(2) The slump retention of PCE is significantly better than that of SNF water-reducing agent. The high fluidity concrete prepared with PCE can still reach the pumping requirement after 1h;

(3) With the increase of dosage, the water reducing rate limit of the PCE is much higher than that of the SNF, and the SNF water-reducing agent has basically reached its limit when dosage is about 2.0%, which shows that the PCE is more suitable for preparing low water-cement ratio high-strength concrete.

The results show that, compared with the SNF water-reducing agent, the PCE superplasticizer has the characteristics of better cement adaptability, lower dosage, higher water-reducing rate, less slump loss of concrete through time, and it  is more suitable for preparing low water-cement ratio concrete.

HIGH PERFORMANCE CONCRETE

Post time: Jul-09-2020