While high-performance fly ash geopolymers offer a demonstrably reduced carbon footprint in the construction industry, their inherent affinity for water (hydrophilicity) can facilitate the accumulation of moisture within the material matrix, potentially leading to the initiation and propagation of internal corrosion. The implementation of hydrophobic functionalization strategies on fly ash geopolymers demonstrably enhances their resistance to corrosive degradation. Nevertheless, a crucial challenge persists in the form of mitigating potential declines in mechanical strength. This investigation endeavors to attenuate the deleterious effects exerted by the hydrophobic aluminosilicate hydrate phase on the material's mechanical properties, while concurrently preserving its superhydrophobic character. Our approach involved the incorporation of a novel composite modifier, wherein polymethylhydrosiloxane (PMHS) served as the principal hydrophobic component. Graphene oxide (GO) was strategically introduced to achieve efficient pore filling, owing to its exceptional dispersibility. Furthermore, the presence of GO reinforces the mechanical performance of the composite due to its inherent superior mechanical properties. Additionally, the well-dispersed GO portion forms nano hydrophobic particles by covalently grafting hydrophobic groups, further enhancing the overall hydrophobicity of the composite. This synergistic interplay between PMHS and GO facilitated the successful development of a high-performance fly ash geopolymer composite characterized by exceptional mechanical strength, three-dimensional superhydrophobicity, and enhanced chemical stability. The graphene oxide reinforced high-performance three-dimensional superhydrophobic hybrid hydrogel geopolymer composites maintained high compressive strength while achieving a water contact angle of 153 ° and a water absorption rate of only 1.7 %. Remarkably, the geopolymer retains its high hydrophobicity even after 24 hours in an acid-base solution, with a contact angle exceeding 140° and water absorption rates lower than 4 %.
Read full abstract