Fly Ash
Fly ash is an extremely fine powder consisting of spherical particles less than 50 microns in size. Fly ash is one of the construction industry's most commonly used pozzolans. Pozzolans are siliceous or siliceous/alumina materials possessing the ability to form cementitious compounds when mixed with lime (calcium hydroxide, or Ca(OH)2) and water.
Fly Ash: Concrete Applications
When portland or portland limestone cement is mixed with water, most of the cement forms insoluble Calcium-Silicate-Hydrate (C-S-H) gel; Calcium Hydroxide - Ca(OH)2 is also formed as part of this reaction. When fly ash is introduced into concrete, it reacts with the Ca(OH)2 to form additional C-S-H gel.
In a properly proportioned mix, fly ash can improve many of the properties of concrete, including:
- Improved workability and consolidation
- Increased flexural and compressive strengths
- Improved pumpability
- Reduced drying shrinkage
- Reduced bleeding and segregation
- Decreased permeability
- Increased resistance to ASR and sulfate attack
- Improved economics
- Reduced water requirements
Fly ash provides a significant contribution to sustainable construction. Its use in concrete production consumes less energy and offers improved efficiency and building performance. Fly ash can contribute to the achievement of LEED (Leadership in Energy and Environmental Design) points.
Product claims are based on proper use in accordance with recognized industry standards. Please contact your Lafarge Cement representative for specific product information, availability, and ordering.
Fly Ash: Geotechnical Applications
Self-cementing fly ash is a hydraulic cementitious material possessing pozzolanic properties and a high calcium oxide content, which allows it to set and harden through chemical interaction with water. The chemical reaction that occurs during the hydration process of self-cementing fly ash is similar to the reaction that takes place during the hydration process of portland cement.
Applications for self-cementing fly ash include:
- Mitigation of shrink/swell properties in expansive clay soils;
- Hot mix asphalt (HMA) pavement recycling;
- Structural fill;
- Stabilization of aggregate bases;
- Soil stabilization; and
- Soil drying.
Product claims are based on proper use in accordance with recognized industry standards. Please contact your Lafarge Cement representative for specific product information, availability, and ordering.
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