A dual-component strategy for ambiently-cured high-toughness red mud-based geopolymer: Modified nano-TiO₂ and sodium polyacrylate

Abstract

In response to the growing demand for sustainable construction materials, this study overcomes the inherent brittleness and poor fracture resistance of red mud-based geopolymer (RBG) through the strategic combination of surface modified nano-TiO₂ (NT) and sodium polyacrylate (SPA). The NT was functionalized with silane coupling agent to improve dispersibility and interfacial bonding, while SPA was added to enhance fracture toughness. Under the condition of ambient curing, the optimum mixture containing 3 wt% (glycidoxypropyltriethoxysilane)-modified NT (GNT) and 0.5 wt% SPA, which achieved a 28 days compressive strength of 43.40 MPa and a flexural strength of 8.16 MPa. The performance index meets the Portland cement (PC 42.5) standards. Microstructural analyses (XRD, FT-IR and SEM-EDS) revealed that the formation of geopolymer gel was increased, the crystallinity was reduced, and the degree of polymerization was improved, which confirmed the effectiveness of this method in production high-toughness and environmentally friendly geopolymer.

Keywords

red mud / geopolymer / modified nano-TiO₂ / sodium polyacrylate / synergistic toughening

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