The feasibility of synthetic surfactant as an air entraining agent for the cement matrix

The effect of the synthetic surfactant combining 50 wt% of polyoxyethylene nonylphenolether (TX-10) with 50 wt% of sodium dodecyl sulfate (K12) on the compressive strength of the cement mortar was investigated in order to explore the feasibility of the synthetic surfactant as an air entraining agent (AEA). The fluidity of the mortar, the process of the cement hydration and the pore size distribution of the hardened mortar were determined for the purpose of analyzing the effect of the AEA on the strength of the hardened mortar. It is found that the suitable dosage of the synthetic surfactant based AEA incorporated with modified lignosulfonate superplasticizer can improve the compressive strength of the cement matrix. The AEA contributes to a better dispersion of cement particles in water, and hence the cement mortar can generate more nuclei and form finer ettringite needles during the cement hydration, resulting in an increase in porosity percentages with small-size pore and a decrease in those with large-size pore. Therefore, the synthetic AEA shows a compressive strength enhancement unless its dosage is excessive.