Silica Fume for Concrete & Cement
Strengthen Critical Infrastructure
& Construction Projects
Silica fume for concrete and fiber cement industries is widely regarded for its numerous advantages in high-performance infrastructure or structural applications. In addition to its pozzolanic properties, silica fume for concrete and cement is an excellent filler due to its particle size. On average, silica fume particles are 100 to 150 times smaller than the regular cement particles. Silica fume's sub-micron size makes it ideal for increasing the overall particle packing of the concrete matrix. The reduction in the size of the capillaries and voids improves the concrete's resistance to chlorides, acids, and sulfates ingress, extending the life expectancy in corrosive environments as well as enhancing the strength for infrastructure and other construction applications.
When silica fume is used in concrete or other cementing applications, it delivers increased toughness and resistance to abrasion and corrosion, improving sustainability and life-cycle cost efficiency. These improved characteristics occur because the compound that largely makes up silica fume (silicon dioxide) easily binds with calcium hydroxide and water to create one of the primary cementing compounds, calcium silicate hydrate.
With building costs and project proposals consistently reaching new highs, planners need to consider all measures to improve the strength and longevity of concrete to reduce the need for costly maintenance or full replacement. While adding silica fume to concrete elevates the up-front project costs, the incredible strength and durability offer a long-term return on investment.
Some real-world examples of high-performance concrete or cementing applications bolstered by densified silica fume include use for highway bridges, parking decks, marine structures, bridge deck overlays, and other applications typically subject to deterioration caused by corrosion, abrasion, or chemical degradation. Utilizing silica fume in concrete can improve protection against deicing salts, seawater, traffic, heavy impact, and other destructive environments. By filling the previously mentioned interstitial gaps within the concrete composition, the cured material can better withstand continual exposure to the corrosive agents that would quickly deteriorate cement without silica fume.
What is Densified Silica Fume for Concrete or Cement?
R-E-D Industrial Products offers silica fume as a supplemental cementitious material in two distinct variations known as undensified and densified silica fume. Densified silica fume is the more applicable material for concrete or cementing applications discussed here. "Densified" refers to the bulk density or compaction of silica fume within a measured cubic meter. Typically measuring between 30 and 50 pounds per cubic foot or 480 and 800 kilograms per cubic meter, densified silica fume is nearly twice as compact as the undensified and excels in applications that have either larger aggregates like you would typically find in concrete or using a high sheer mixer. It is necessary to break the silica fume into a finer powder (this would be analogous to what is required to get a singular snowflake from a loosely compacted snowball). Using these sheering forces to "grind" the densified silica fume grain increases the overall surface area, providing additional areas to produce even more calcium silicate hydrate.
Beneficial Properties of Silica Fume in Concrete & Cement
Pozzolanic Reaction
As mentioned earlier, silica fume for concrete or cement reacts with lime during cement hydration to form additional calcium silicate hydrate (C-S-H) and aluminosilicate hydrate. These cementing compounds create a dense matrix.
Filler Effect, Porosity & Corrosion Resistance
As mentioned earlier, silica fume for concrete or cement reacts with lime during cement hydration to form additional calcium silicate hydrate (C-S-H) and aluminosilicate hydrate. These cementing compounds create a dense matrix.
Alkali Reaction
Silica fume protects the concrete against undesirable alkali reactions. This happens in several ways:
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Reduction: The additional pozzolanic reaction between silica fume and calcium hydroxide reduces the availability of ions for ASR.
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Improvement: The fine particles of silica fume create denser concrete, reducing permeability and limiting water ingress. This is important because water is a necessary component for ASR gel expansion.
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Dilution: Replacing part of the Portland cement with silica fume dilutes the overall alkali content in the concrete mix.
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Binding: Formation of additional C-S-H can also bind alkalis, reducing the available free alkali ions.
Strength
Silica fume improves the concrete’s particle packing, adhesion effects, and pozzolanic reactivity. These improvements directly impact the mechanical properties, especially strength.
Freeze-Thaw
Silica fume reduces concrete permeability. A reduction in chloride and sulfate ingress has been proven to slow down irreversible degradation significantly.
Sustainability Benefits of Silica Fume for Concrete & Cement
R-E-D Industrial Products' densified and undensified silica fume for concrete and cementing applications provides benefits in function and application sustainability. See the information below to discover how silica fume can provide confidence that you are making a cost-effective and sustainable choice for your next project. R-E-D Industrial Products' core values of reliability, efficiency, and dependability are all key components linked to our pursuit of sustainability and environmentally conscious distribution.
Applicability for Sustainability:
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Increased strength in concrete structures
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Longer durability means less frequent replacement
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Resistance to alkali-silica reaction (ASR)
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Low permeability to intrusion from corrosives such as water, salt, chloride, and other natural elements in challenging environments
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Reduction of life cycle costs
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Abrasion and impact resistance to withstand continuous traffic or loads
Implementations:
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Low permeability makes it well suited for structures that are immersed or near oceans, rivers, and water sources such as bridges, dams, and tunnels.
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The ability to protect from abrasion and impact resistance provides a boost in protection for rebar from deterioration and replacement.
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Increased strength for use in more wear-and-tear concrete structures that need to reach the standard life cycle span of 50 years.
Why Silica Fume?
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Increase sustainability in concrete projects
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Lower life cycle costs of infrastructure and building projects
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An ethically sourced product that can boost your green initiatives