Silica Fume - Analytical Products / Alfa Chemistry

CAT

APS012157

Matrix	Dust and Ash; Other Ashes
Shipping	Room Temperature
Storage Conditions	Room Temperature
Subcategory	Additional process materials, National Institute of Science and Technology (NIST), Ferro alloys and Si alloys

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Case Study

Silica Fume Used for Strength Enhancement and Microstructure Optimization in Geopolymer Mortar

Wang, Tao, Xiangqian Fan, and Changsheng Gao. Structures. Vol. 69. Elsevier, 2024.

Silica fume plays a critical role in improving the performance of geopolymer mortar, a sustainable alternative to ordinary Portland cement mortar. In this study, silica fume was incorporated into fly ash-slag-based geopolymer mortar to investigate its impact on mechanical strength and microstructure.
Mortars were prepared by dry mixing fly ash, slag, silica fume (0-20 wt%), and fine sand, followed by the addition of alkaline activator and water. The mixture was molded, sealed with plastic film, and cured at 20 ± 3 °C and 95% humidity for up to 28 days. The results demonstrated a positive correlation between silica fume content and compressive strength, with the highest strength observed at 20% silica fume. Flexural strength increased initially and peaked at 10% silica fume before declining.
Mechanistically, silica fume exhibits a pronounced micro-filling effect that reduces porosity and refines the internal pore structure. Additionally, it accelerates gel formation during polymerization, enhancing the overall matrix density. Microstructural analysis revealed that the amount of reaction products correlated more strongly with compressive strength than pore structure parameters.
These findings highlight the dual function of silica fume as both a reactive pozzolanic component and a microstructural densifier, making it a vital additive for enhancing the mechanical integrity and durability of geopolymer mortar systems.

Silica Fume Used for the Preparation of Alkali Activator in Low-Carbon Geopolymer Applications

Lin, Minguo, et al. Journal of Cleaner Production 498 (2025): 145214.

Silica fume has been effectively utilized as a key component in the preparation of alkali activators for geopolymers, offering a sustainable alternative to conventional alkali silicates in the production of low-carbon construction materials. In this study, a silica fume-based activator was synthesized and employed in the preparation of fly ash and slag-based geopolymer binders, aiming to reduce both production costs and CO₂ emissions.
The silica fume-based activator was prepared by dissolving sodium hydroxide in deionized water, followed by the addition of silica fume to control the solution modulus (0.8-2.0). The mixture was aged at 20-80 °C for 24 hours to ensure complete reaction and homogenization.
Geopolymer pastes were formulated by mixing fly ash and slag (SiO₂/Al₂O₃ ratios of 0.5-4.0) with 10-25 wt% of the prepared activator solution at a constant water-to-solid mass ratio of 0.4. After molding and curing under controlled temperature (20 ± 2 °C) and humidity (95%), compressive strength development was monitored over 3, 7, and 28 days.
The results demonstrate that silica fume, when used in activator formulation, not only simplifies the synthesis process but also enhances the mechanical performance of the geopolymer matrix. This approach underscores the viability of silica fume in developing cost-efficient, eco-friendly building materials through alternative geopolymer technology.

Silica Fume Used for Enhancing Strength and Impact Resistance in Alkali Activated Concrete Applications

Maganti, Tejeswara Rao, and Krishna Rao Boddepalli. Construction and Building Materials 471 (2025): 140702.

Silica fume has been effectively utilized to enhance the mechanical performance of alkali activated concrete (AAC), particularly in formulations incorporating industrial by-products such as fly ash and ground granulated blast furnace slag (GGBS). This study investigates the synergistic effect of silica fume with steel, polypropylene, and hybrid fibers in improving compressive strength, ductility, and impact resistance of sustainable concrete composites.
Silica fume was incorporated at 0%, 5%, 10%, and 15% by binder weight, while GGBS content was maintained at 50%. The substitution of fly ash with increasing silica fume levels significantly improved the matrix density and fiber dispersion. Hybrid fiber systems, combining steel and polypropylene fibers, were employed at various volume fractions to optimize mechanical response.
Experimental findings revealed that a mix containing 10% silica fume and 2.5% steel fibers achieved the highest compressive strength (110.45 MPa), while a blend of 10% silica fume with 2% hybrid fibers yielded superior impact resistance (58.2 kN·m). Optimization via response surface methodology (RSM) suggested ideal composition at 11.521% silica fume and 1.893% hybrid fibers.
The study concludes that silica fume significantly contributes to the enhancement of AAC by improving fiber-matrix interactions and mechanical durability, presenting a sustainable solution for high-performance construction materials.