98% Undensified Silica Fume

1️⃣ Product Overview

98U Silica Fume is a highly reactive, undensified (as-produced) microsilica product with a silica content no less than 98%. It is collected from the fumes generated during the production of high-purity silicon or ferrosilicon in submerged-arc furnaces, where silica vapor oxidizes and condenses. This ultra-fine, amorphous powder has an average particle size between 0.1-0.3 μm and an exceptionally high specific surface area (15,000-25,000 m²/kg), resulting in extremely strong pozzolanic activity. The "U" denotes its loose, low-bulk-density physical form.

2️⃣ Product Specifications

3️⃣ Performance Characteristics

· Ultra-High Pozzolanic Reactivity: The combination of over 98% amorphous silica content enables rapid reaction with calcium hydroxide from cement hydration, generating additional dense calcium silicate hydrate gel.

· Superior Micro-Filler Effect: The ultra-fine spherical particles efficiently fill voids between cement grains, significantly reducing porosity, enhancing compactness, and improving impermeability by 5-15 times.

· Substantial Mechanical Enhancement: Incorporation of 8%-12% of 98U Silica Fume can increase 28-day compressive strength by 20%-35% and flexural strength by 15%-20%.

· Exceptional Durability: Dramatically improves resistance to chloride penetration, sulfate attack, and alkali-silica reaction. Significantly enhances carbonation resistance and freeze-thaw cycling performance.

· Improved Fresh Properties: The high surface area and activity effectively enhance the cohesion and water retention of concrete, reducing bleeding and segregation.

4️⃣ Application Fields

· Ultra-High & High-Performance Concrete: A key component for UHPC, RPC, and HPC used in critical structures like bridges and high-rises.

· High-Durability Concrete: Ideal for marine structures, hydraulic dams, tunnels, and industrial floors in harsh environments requiring extreme durability.

· High-Strength Grouts & Repair Mortars: Essential for non-shrink, high-flow, high-early-strength applications like equipment anchoring and structural repair.

· Refractories & Ceramics: An additive for advanced unshaped refractories to improve hot strength, thermal shock, and corrosion resistance.

· Chemically Bonded Ceramics & Geopolymers: Serves as a reactive silica source for geopolymerization in producing high-performance specialty materials.

5️⃣ Usage Guidelines

· High-Range Water Reducer is Mandatory: To counteract the high water demand caused by its enormous surface area, must be used with superplasticizers to maintain workability.

· Optimized Dosage Design: The recommended dosage is 8%-12% by mass of cementitious materials, with the optimum determined through systematic mix design.

· Ensure Thorough Dispersion: Mixing time should be extended by 1.5-2 minutes using a forced-action mixer to guarantee uniform distribution.

· Enhanced Early Moist Curing: Due to high water consumption from secondary pozzolanic reactions, prompt and diligent moist curing must commence immediately after final set and be maintained for a recommended minimum of 14 days to prevent early-age plastic shrinkage cracking.

6️⃣ Packaging & Storage

· Packaging: Given its low bulk density, it is typically supplied in sealed, plastic-lined woven jumbo bags of 500kg or 600kg for ease of handling and dispensing. Smaller bags are available upon request.

· Storage Conditions: Must be stored in a cool, dry, and well-ventilated warehouse. Strictly protect from moisture, water, and bag damage.

· Shelf Life: 24 months when stored under recommended, intact, and sealed conditions.