Relationship Between Elastic, Chemical, and Thermal Properties of SiO2 Flint Aggregate

Understanding the relationship between elastic, chemical, and thermal properties is essential for the prevention of the behavior of SiO₂ flint aggregates during their application. In fact, the elastic properties of silica depend on chemical and heat treatment. In order to identify the crystallite sizes for natural SiO₂ before and after chemical treatment samples, Williamson-Hall plots and Scherer's formulas are used. The silica nanofibers obtained and their microstructure changes under thermal and chemical treatment are characterized using different techniques (XRD, VP-SEM, TEM, FTIR, TDA, and TGA). Both the strains (ε) and the crystallite sizes (DW-H) are obtained from the slope and from the βcosθ-intercept of a graph, respectively. The crystalline quality is improved upon heating, as shown by the decrease in the FWHM of the SiO₂(101) peaks, which is confirmed by Fourier transform infrared spectroscopy (FTIR). The microstrain estimated at 1.50 × 10^-4 units for natural SiO₂ is smaller than that for SiO₂ after chemical attack which is estimated at 2.01 × 10^-4 units. Based on the obtained results, SiO₂ characterized with controlled micromechanical, thermal, and chemical properties may be used as a filler to improve the performance properties of the strength, microstructure, and durability of some composites.