Synthesis of Amphiphilic Polyether-Modified Silicone Oil Polymers and the Application of Their Micelles in Enhancing the Overall Waterproofing and Corrosion Resistance of Cement-Based Concrete Materials

In this study, a series of amphiphilic polyether-modified silicone oil (PMSO) polymers with hydrophilic–lipophilic balance (HLB) values ranging from 3.5 to 5 were synthesized via hydrosilylation. These polymers are self-emulsifying and can form stable micelles in water without the need for external emulsifiers, with micelle sizes ranging from 79.9 to 161.4 nm. For the first time, such amphiphilic micelles were employed as an internally incorporated hydrophobic admixture to investigate the waterproofing and corrosion resistance of cement-based materials. The results showed that PMSO micelles with an HLB value of 4 significantly reduced the water absorption of cement mortar and improved mechanical properties by enhancing the compactness and crystallinity of the cement matrix. At a dosage of 0.5 wt% PMSO in mortar, the water absorption at 48 h was reduced by 50.27% compared with the control group, and the inner and outer contact angles of the mortar specimens reached 105° and 126°, respectively. The chloride diffusion coefficient of concrete decreased by 70.8% relative to the control group. At an appropriate dosage (0.1 wt%), the flexural strength of the mortar at 28 days increased by 12.50%, and the compressive strength increased by 14.19% compared with the control group. Low-field nuclear magnetic resonance (NMR) was used to determine the changes in the pore structure of mortar specimens before and after the addition of PMSO micelles. The experimental results showed that the addition of PMSO micelles reduced the number of harmful large pores, resulting in a denser microstructure. Finally, the corrosion resistance of concrete was evaluated via electrochemical accelerated-corrosion aging tests. The cracking time of concrete containing PMSO micelles was extended from 144 h (control group) to 240 h, demonstrating improved corrosion resistance.