Is 3812 specification for fly ash?
This standard was first published in 1966 in three parts to cater to the requirements of fly ash for three specific uses: Part 1covering use of fly ash as a pozzolana, Part 2 covering use of fly ash as an admixture for concrete, and Part 3 covering use of fly ash as fine aggregate for mortar and concrete.
Is code for specification of fly ash?
1.2 Pulverized fuel ash to be used as pozzolana in cement, cement mortar and concrete in accordance with this standard shall be fly ash only which may be either in as collected condition or beneficiated, segregated or processed.
What is fly ash in chemistry?
Chemistry. Fly ash consists primarily of oxides of silicon, aluminum iron and calcium. Magnesium, potassium, sodium, titanium, and sulfur are also present to a lesser degree. When used as a mineral admixture in concrete, fly ash is classified as either Class C or Class F ash based on its chemical composition.
How do you test for fly ash?
The fineness of fly ash can be determined by wet sieving (Section 7.2), dry sieving (Section 7.3) or with the Blaine air permeability apparatus (Section 7.4). This test method describes the determination of fly ash fineness by wet sieving on a 45/. ~m sieve (ISO 565).
How much fly ash can replace cement?
Typically, 15 percent to 30 percent of the portland cement is replaced with fly ash, with even higher percentages used for mass concrete placements. An equivalent or greater weight of fly ash is substituted for the cement removed.
Where does the fly ash in a boiler come from?
Fly ash. Fly ash or flue ash, also known as pulverised fuel ash in the United Kingdom, is a coal combustion product that is composed of the particulates (fine particles of burned fuel) that are driven out of coal-fired boilers together with the flue gases. Ash that falls to the bottom of the boiler is called bottom ash.
Why is there a standard for fly ash?
The Sectional Committee responsible for the formulation of this-standard subsequently felt that the performance of fly ash as a pozzolana or an admixture or a fine aggregate, was complementary and not separable and hence requirements of fly ash for these uses should be covered by a single standard.
When was the fly ash standard first published?
This standard was first published in 1966 in three parts to cater to the requirements of fly ash for three specific uses: Part 1 covering use of fly ash as a pozzolana, Part 2 covering use of fly ash as an admixture for concrete, and Part 3 covering use of fly ash as fine aggregate for mortar and concrete.
What kind of fuel is pulverized fly ash made of?
Such fly ash are normally produced from burning anthracite or bituminous coal and has pozzolanicproperties. 3.3 Calcareous Pulverized Fuel Ash — Pulverized fuel ash with reactive calcium oxide not less than 10 per~ent by mass.
