Waterproof geopolymer composites modified by hydrophobic particles and polydimethylsiloxane

• Published in: Composites. Part B, Engineering Engineering, 2022-05, Vol.237, p.109865, Article 109865
• Main Authors: Ruan, Shengqian, Chen, Shikun, Lu, Jiayu, Zeng, Qiang, Liu, Yi, Yan, Dongming
• Format: Article
• Language: English
• Subjects: Geopolymer composites; Microstructures; Radiography; Wettability
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2022.109865

Geopolymer is a green porous aluminosilicate material that can be tailored with fillers and additives to achieve various functions. In this work, waterproof geopolymer composites fabricated by blending hydrophobic metakaolin and quartz particles, as well as PDMS agents, were innovatively developed. The contrast-enhancing X-ray computed tomography and gravimetry were used to rate their waterproof efficacy. The results show that water absorption is greatly inhibited in PDMS-hydrophobic particle composites due to the capillary surface modification and long tortuous water transport channels caused by micron-sized particles and macropores. A new low-sorptivity stage lasting ∼150 h occurs at the beginning of the water absorption process, and the final absorbed-water volume significantly reduces. This work reveals the waterproof mechanisms and water absorption kinetics of geopolymer composites with hydrophobic materials and points the way to waterproof engineered geopolymer materials.