Exploring the Use of Silicone Oil Ash in Cement-Based Mortars: Mechanical Properties, High-Temperature Performance, and Resistivity

This study investigates the utilization of silicone oil ash (SOA), a silicon-rich byproduct of polyacrylonitrile (PAN)-based carbon fiber production, in cement-based mortars to improve mechanical strength, high-temperature performance, and electrical resistivity. Due to its fine particle size and amorphous silica content, SOA has the potential to act as both filler and pozzolanic material in cementitious composites. Experimental studies were carried out on mortars containing different levels of SOA to evaluate their mechanical properties and durability. The findings of the present study demonstrated that the incorporation of SOA into concrete enhances its flexural and compressive strengths, particularly at moderate replacement levels. At the 28-day mark, both flexural and compressive strengths improved with the incorporation of SOA, particularly at 0.3% content, which yielded the most notable enhancements compared with the control sample. The findings of this study suggest that the optimal SOA dosage is one that maximizes strength benefits, and that excessive amounts may lead to particle agglomeration, which in turn limits further improvements. In addition, mortars containing SOA exhibited improved resistance to elevated temperatures, with reduced loss of strength at elevated temperatures. Electrical resistivity measurements also suggest that its inclusion may contribute to reduced chloride ion permeability, potentially improving durability. Microstructural analyses, including X-ray diffraction (XRD) and Fourier transform infrared (FTIR), revealed that no significant chemical interaction occurs between SOA and the cement hydration products. This emphasizes that its contribution is primarily through matrix densification. The results indicated that SOA does not exhibit significant pozzolanic reactivity but enhances mechanical strength and durability through a filler effect, improving particle packing and reducing porosity in the cementitious matrix. The results suggest that SOA could be a promising alternative material for sustainable construction applications, offering both environmental and performance benefits.