Fly ash from hard coal combustion is a renowned addition for production of ordinary concrete, which has been confirmed by numerous research and implementations worldwide for over 60 years.

Folder - Fly ash Folder - Popilek_CZ Folder - Popolcek_SK

The most important arguments confirming suitability of ash include:

• improvement of concrete workability properties
• improvement of tightness of a structure
• reduction of hydration heat 
• increase of resistance to chemical aggression
• participation of ash in cement binding reactions 
• higher resistance of concrete over long period of time
• reduction of production costs of the concrete mixture.

According to PN-EN 206-1 fly ash is treated as type II mineral addition, i.e. fine-grained non-organic material with pozzolanic properties.
Detailed conditions, which have to be fulfilled by ash for concrete as specified in PN-EN 450 “Fly ash for concrete”, where categories of fly ash are distinguished depending on loss on ignition:

and depending on fineness (amount retained on 0,045 mm sieve):

Requirements of chemical properties::

Requirements of physical properties

 Influence of fly ash on properties of fresh concrete

Basic changes occurring due to use of fly ash include demand for water and workability. For stable workability, the demand for water usually decreases by 5 - 15 % as compared with a mixture of the same binding material containing Portland cement only. The concrete mixture including fly ash is cohesive and shows reduced tendencies for draining. The mixture may be pumped and moulded with the use of a sliding method and concrete finishing operations using fly ash are simpler. Influence of fly ash on properties of fresh concrete is connected with the shape of fly ash. Most of its grains are spherical and this property has been assigned with an effect of “bearing balls”, which improves workability. Fly ash delays the mixture binding.

Influence of fly ash on concrete durability

Fly ash added leads to limitation of alkali-silica reaction. Based on the current experience in application of fly ash for concrete, fly ash has been known to reduce durability of concrete cutting for 28 days. Following the period of three months, durability of concrete with fly ash added becomes usually similar to durability of the same concrete, which, however, was made with the use of cement. Later, following a longer period of curing, durability of concrete with fly ash added is usually higher than that of comparable concrete. This results from pozzolanic reactions, which are long-term processes and they also found that during the period of one year, approx. 50 % has not reacted yet. The delay in binding and slowing down of concrete hardening contributed, on the other hand, to decrease of thermal effects of hydration of the mixture components.

The company’s documents permitting use:

• KIS 10 01 02
• Certificate of constancy of performance
• Declaration of conformity  for fly ash A
• Declaration of conformity for fly ash B

• Certificate of constancy of performance - Siechnice
• Declaration of conformity for fly ash from Siechnice - B
  

• Certificate of constancy of performance - Wrocław
• Declaration of conformity for fly ash from Wrocław - A
• Declaration of conformity for fly ash from Wrocław - B

• Certificate of constancy of performance - Kraków
• Declaration of conformity for fly ash from Kraków - A
• Declaration of conformity for fly ash from Kraków - B
  

• Certificate of constancy of performance - Gdynia
• Declaration of conformity for fly ash from Gdynia - B
  

• Declaraton of conformity for fly ash from Gdańsk -  B
• Declaration of conformity for fly ash from Gdańsk -  C