The Blaine value is a standardised measure of the fineness of cement and similar powdered materials, determined by the Blaine air permeability method and expressed as the total surface area per unit mass, typically in square centimetres per gram (cm2/g).
How it works
The Blaine value is determined using a Blaine air permeability apparatus, a laboratory device that measures how easily air passes through a compacted bed of cement powder. The test follows standards such as ASTM C204 or EN 196-6. A known quantity of cement is packed into a cylindrical cell to a defined porosity, and air is drawn through the sample. The time it takes for a measured volume of air to pass through the powder bed is recorded and compared against a reference material with a known specific surface area.
A finer cement has a larger total surface area and therefore restricts airflow more, resulting in a longer passage time and a higher Blaine value. Typical ordinary Portland cement has a Blaine value between 3,000 and 4,000 cm2/g. Rapid-setting or high-early-strength cements are ground finer, reaching values of 4,500 cm2/g or more, while coarser blended cements may fall below 3,000 cm2/g.
Application in construction
The Blaine value is an important quality control parameter in cement manufacturing and concrete mix design. Fineness directly influences how quickly cement hydrates when mixed with water: finer particles react faster, generating early strength but also producing more heat of hydration. This matters for builders because:
High-Blaine cements accelerate setting and strength gain, useful for cold-weather concreting or fast-track construction schedules. However, the increased heat of hydration can cause thermal cracking in mass concrete pours if not managed properly.
Low-Blaine cements hydrate more slowly, producing less heat and offering better long-term durability in some applications, but they require longer curing periods before formwork can be stripped or loads applied.
Concrete technologists specify Blaine values alongside other parameters such as chemical composition and particle size distribution to optimise concrete performance for a given application.
Related terms
- Portland cement
- Heat of hydration
- Concrete mix design
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