|
| |
General Information |
|
|
| |
PFA, Pyramid Fly Ash, is collected from rich coal burnouts after electrostatic precipitation process. It is commonly known as Fly Ash.
Civil engineers have known the use of Fly Ash since centuries. The great durability of the Egyptian Pyramids and ancient Roman structures is the result of use of pozzolanic material with lime mortar.
PFA is a pozzolana having high pozzolanacity. It is a finely divided material that reacts with Calcium Hydroxide and Alkalis to form compounds possessing cementitious properties. PFA is selectively collected dry Fly Ash to obtain highest pozzolanic property with reactive Alumino Silicate Glass, fine enough to provide high reactive surface area for the solid state chemical reactions.
The use of Fly Ash in concrete for structural fills is governed by IS 3812 Part II of IS 456.
In climactic conditions where temperatures exceed 35°C, experts recommend the use of Fly Ash. Research carried out over the last 15 years by leading institutes such as Canadian Center for Mineral and Energy Technology (CANMET), The Kolkata University, Ash Utilization Symphonic, USA, have revealed that fine Fly Ash, when used in concrete in synergy with O.P.C., gives reduced permeability and very durable concrete.
|
| |
|
|
|
| |
PYRAMID CLASS ‘C’ FLY ASH |
|
|
| |
PYRAMID CLASS ‘C’ fly ash is produced from the burning of younger lignite or sub bituminous coal in addition to having pozzolamic. Properties also has some self cementing properties. In the presence of water class ‘c’ fly ash will harden and gain strength over time. Pyramid Class ‘C’ fly ash generally contains more than 20% lime (CaO) unlike class f self cementing Class ‘C’ fly ash does not require an activator. Pyramid class ‘c’ flay ash which has a high lime content reacts to some extent direct with water in particular some C 2 S may be present in the fly ash and this compound reacts earlier than Class F fly ash .
Pyramid class ‘C’ fly ash has all characteristics of high strength, high durability, abrasion
resistance, sulfate resistance & chloride resistance.
Application uses Pyramid Class ‘C’ Fly Ash can be used in
- Manufacturing of concrete
- Manufacturing paver blocks, Manufacturing Hume pipes and Solid cement bricks.
- PCC concrete PQC concrete
- Fly Ash brick and light weight concrete blocks
- Can replace cement in up 75% in bricks masonry and plastering.
Benefits of Pyramid Class ‘C’ Fly Ash in plastic stage of concrete and mortar
- Lesser water demand for desired workability: Pyramid class ‘C’ reduces the amount of water needed to produce a given slump. The spherical shape of PYRAMID CLASS ‘C’ FLY ASH Particles and its depressive ability provides water – reducing characteristic similar to water reducing admixture. Water reduction up 6 to 8 % is possible.
- Cohesion of concrete is improved : The spherical shape and depressive nature helps in increasing the cohesiveness of concrete. The PYRAMID CLASS ‘C’ FLY ASH produces more cement paste then O.P.C. and lubricates the aggregates nicely.
- Bleeding and segregation are minimized : The better lubricated aggregates by fine particles of PYRAMID CLASS ‘C’ FLY ASH ensure better blocking of water capillaries ensuring minimum bleeding & segregation of the mix
- Better workability retention: The spherical shape provides a ball bearing effect to the concrete resulting in a free flow concrete with better slump retention then the control mix.
- Reduced plastic shrinkage cracks: Reduced heat of hydration and cohesive concrete by incorporation of PYRAMID CLASS ‘C’ FLY ASH ensure minimized or no plastic shrinkage of the concrete or mortar.
INHARDEN STAGE OF CONCRETE & MORTAR
- More overall strength than plain O.P.C. concrete is ensured because of continuing pozzolanic Reaction between high reactive silica in PYRAMID CLASS ‘C’ FLY ASH with free in cement paste.
- The pore reinforcement due to excellent particle size distribution of PYRAMID CLASS ‘C’ FLY ASH & pozzolanic reaction the concrete & mortar become almost impervious.
- Better gel spacing is achieved due high reactivity silica in PYRAMID CLASS ‘C’ FLY ASH resulting in to a strong & durable concrete or mortar.
- The concrete & mortar are protected from sulphates & chloride attack because of reduced permeability & reduced free lime the hydrate cement paste because of pozzalanic reaction the leachable free lime is converted in to additional calcium silicate.
- The use of PYRAMID CLASS ‘C’ FLY ASH also reduces the alkaline silica reaction between the reactive aggregates & alkaline content of cement namely K 2 O & Na 2 O.
- The use of PYRAMID CLASS ‘C’ FLYASH increases the flexural strength by 10 to 15% the tensile strength is also improved.
|
| |
|
|
|
