Conditioned PFA
ScotAsh supplies two types of conditioned PFA:
- Conditioned PFA, taken direct from Longannet Power Station and conditioned with water prior to delivery
- Lagoon PFA, which has been slurried at Longannet and Cockenzie Power Stations and pumped to lagoons. This material is excavated from the lagoons and allowed to stabilise to reduce its water content. If desired, it can also be screened prior to despatch.
Conditioned PFA can be used as a general or structural fill material, for highway construction, or for capping. It can also be used as an addition in concrete, as an aggregate/filler in cementitious grouts, or bituminous road materials and in cement manufacture.
Quality
The main documents controlling Conditioned PFA are:
- Specification for Highway Works (SHW)
- BS 3892: Part 2: 1996 - as a Type 1 addition
- BS 3892: Part 3: 1997 - for use in cementitious grouts
- TRL Report TRL519 - specification of pulverised fuel ash for use as general fill
Conditioned PFA is low density so can be used as a fill material over weak ground. When used in grout it gives good yields. There is very little consolidation after placing and the material offers immediate strength from the high value of apparent cohesion an a high angle of shearing resistance, while the continuing reaction between PFA and free lime means that it offers strength gains with time.
Conditioned ash is self-supporting, minimising the need for shoring. It has low permeability, assisting water run-off and it is a stable material chemically and physically. The spherical shape of the ash particles provides the additional benefits of a reduced water to solids ration, reduced bleeding and good flow properties.
Download our Conditioned PFA product information leaflet or the Health & Safety information leaflet
