TiO2–SiO2 nanocomposites from technological wastes for self-cleaning cement composition

Abstract

Nanocomposites TiO2–SiO2 that can produce self-cleaning concretes with increased strength were studied in this work. We synthesized TiO2–SiO2 nanocomposites from industrial raw materials and waste products. We studied TiO2–SiO2 properties by Fourier transform infrared spectra, X-ray diffraction, and thermogravimetric/derivative thermogravimetric analyses. We established that obtained TiO2–SiO2 nanocomposites to comprise rutile and amorphous silica (TS-1), a mineral-like weakly-crystallized ivanyukite (TS-2), anatase and amorphous silica (TS-3, TS-4). The specific surface area of the studied powders changed in the range 50–534 m2 g−1. We evaluated the photocatalytic performances of the TiO2–SiO2 nanocomposites in methylene blue aqueous solution under UV. TS-2 and TS-3 samples performed a higher photocatalytic activity than a commercial P25 photocatalyst. We added 1.0 wt % TiO2–SiO2 to cement paste and studied its properties and structure by compressive strength test, TG/DTA analysis and scanning electron microscopy. The resulting cement paste determined to have increased compressive strength, reduced pore size, decreased structure defects and increased density of cement stone. The cement paste determined to possess self-cleaning properties both in the UV and visible light.