Effect of utilization of polycarboxylate- based water reducing admixture containing different surface active agent on properties of cementitious systems.

In this study, the utilization effect of high-range water reducing admixtures (HRWR) with different ethylene oxide/propylene oxide (EO/PO) based air-entraining surfactants on the permeability, compressive strength and freezing-thawing resistance of concrete mixtures was investigated. For this purpose, firstly, hybrid silicone air-entraining surfactants with a silicon content of 20, 33 and 38,5% were synthesized. Then, HRWRs containing 7 different air-entraining surfactants were produced by using the substitution and synthesis methods. In HRWRs produced by the substitution method, 3 and 5 wt.% of HRWR were substituted with EO/PO based hybrid silicone air-entraining surfactant. In the other method, EO/PO based hybrid silicon air-entraining macromonomers were bonded to the HRWR at ratios of 1, 3 and 5 wt.% during its synthesis process. According to the test results, replacing HRWR with hybrid silicone surfactants increased the admixture demand to provide the target slump value in concrete mixtures. The use of air-entraining surfactants containing 20% and 33% silicon in HRWR by substitution method positively affected the permeability and compressive strength of concrete mixtures, while the increase in this ratio to 38.5% by using the synthesis method did not affect these properties significantly. The presence of surfactant with 20% silicon in 3 and 5% of admixture and with 33% silicon in 5% of admixture positively affected the freezing-thawing resistance of concrete mixtures. However, the use of surfactants with 33% silicon content in 3% of admixture and 38.5% silicon in 1, 3 and 5% of admixture showed a negative effect on the freezing-thawing performance of the mixtures.