The Production and Durability of Superhydrophobic Foamed Concrete

The durability problem caused by the high-water absorption of foamed concrete restricts its further development and application. This study aimed to improve the durability of foamed concrete by transforming its performance from hydrophilic to superhydrophobic. Firstly, polydimethylsiloxane-modified superhydrophobic bulk foamed concrete was produced through physical foaming. Then, multiple durability tests, like mechanical wear, acid-alkali-saline resistance, ultraviolet aging, and extreme temperatures resistance tests, were carried out to assess its performance. Finally, the mechanism of superhydrophobicity also was studied. The results indicated that the volumetric and capillary water absorption of the superhydrophobic foamed concrete decreased by 72.4% and 92.6%, respectively, compared to ordinary foamed concrete. The dry densities of ordinary foamed concrete and superhydrophobic foamed concrete were 720 kg/m3 and 850 kg/m3, respectively. Superhydrophobic foamed concrete exhibited excellent wear resistance and resistance to ultraviolet aging. The contact angles after 10 m polishing and 168 h of ultraviolet irradiation were 152.1 degrees and 152.2 degrees, respectively. High temperature increased its hydrophobicity, and the contact angle increased to 157.1 degrees at 200 degrees C. Additionally, electrochemical tests proved its better chloride ion corrosion resistance, and the corrosion potential and corrosion current of the superhydrophobic foamed concrete after 7 days were -0.190 V and 3.177 x 10-6 A, respectively. Therefore, the superhydrophobic bulk modification technique shows considerable potential for enhancing the durability of foamed concrete applied in various scenarios.