Preliminary exploration of a novel high-performance air entraining agent based on sodium dodecyl sulfate added self-made fluorocarbon surfactant

Abstract

Sodium dodecyl sulfate (SDS), an air entraining agent (AEA), is used to improve the frost resistance of concrete, but the effectiveness of SDS is urgent to be improved because it is easily weakened by many factors. In this work, a novel high-performance AEA (HPAEA) was prepared by compounding sodium dodecyl sulfate (SDS) with the self-made fluorocarbon surfactant (S-FC). The performance of HPAEA in cement paste solution and in mortar were evaluated and the improvement mechanism was explored. The results of foamability and foam stability in cement paste solution, air content and air-void parameters in cement mortar showed that S-FC could greatly promote the foam properties of SDS and optimize the air-void structure in entrained mortar. When the concentration of S-FC reached 0.2 wt%, foamability, foam stability, fresh air content of HPAEA was 2.9 times, 16.5 times, and 1.6 times higher than that of SDS, respectively. The air-void spacing factor in hardened mortar was reduced by more than 50%. The improvement mechanism of the effectiveness of HPAEA was revealed by the lower surface tension and better comprehensive property of the bubble liquid film, because there was synergistic effect between SDS and S-FC. It was concluded that the novel HPAEA obtained by compounding SDS with S-FC had a potential to significantly improve the frost resistance of concrete.