EN 450 Fly Ash
Overview
EN 450 Fly Ash can be used as a replacement for Portland cement in virtually any concrete application. For general purpose applications, concrete containing 25%-40% PFA is most suitable.
ScotAsh Fly Ash N is a quality-assured fly ash imported from Europe and is suitable for use in combination with Portland Cement.
Uses and Benefits
EN450 fly ash in concrete offers improved rheology, reduced bleeding and uses less water than Portland cement concretes. It also improves pumpability and gives an excellent finish.
Trojan Cements
Overview
Our Trojan cements generally contain between 21% and 35% fly ash, (Pulverised Fuel Ash). Our primary product is Trojan T27, which contains 27% fly ash and has been designed to optimise performance in terms of workability and long-term durability, without compromising early strength
Uses and Benefits
Blended fly ash-based cements can be used in virtually any application where Portland cement would normally be used.
As fly ash is a pozzolana, reacting with free lime liberated from the hydration of Portland cement to form additional cementitious hydrates, it continues to gain strength with time. Trojan cements offer a lower heat of hydration, reduced shrinkage and creep and are resistant to sulfate attack and reduced chloride ingress.
Trojan Grouts
Overview
Trojan general purpose grouts are blends of fly ash (Pulverised Fuel Ash) and Portland cement. Various blends are available, ranging from 1:1 PFA:PC (TGP1) to 20:1 PFA:PC (TGP20), depending on the properties required.
Uses and Benefits
The fly ash in Trojan General Purpose Grouts consists of hollow spheres of between one and 150 microns in size. These form a continuous grading that improves the rheological properties of the grout.
In addition, fly ash is a pozzolana and by reacting with the free lime released from the hydration of Portland cement it forms additional cemenitious hydrates, resulting in a denser, less permeable grout.
Stabilisation Products
Overview
ScotAsh manufactures bespoke stabilisation solutions that can be used to stabilise contaminated land or to treat trench arisings, enabling spoil to be re-used in recycled roads projects.
Contaminated land, soils, sludges and industrial wastes can be treated using cementitious binders in a process called stabilisation/solidification (s/s). The chemical properties of the cementitious products immobilise contaminants (stabilisation) and the physical binding properties create a solid matrix (solidification).
Materials that are not contaminated but are unsuitable as a construction material such as wet sludges, dredgings or tunnel drilling muds can be treated using the same processes and products to make them suitable for use as construction materials.
ScotAsh also produces Trojan Envirocems. These are environmental cements used for stabilisation that are custom designed to meet the requirements of each specific project. Stabilisation and/or solidification techniques using cementitious binders are well established in both the US and the UK. The technology is capable of immobilising a range of inorganic and organic pollutants.
ScotAsh works closely with clients and often collaborate with expert third parties to develop innovative stabilisation solutions. The company teamed up with Professor George Fleming and a team at Strathclyde University to provide a solution for stabilising tributyl tin in harbour sludges on Tyneside.
In Scotland, ScotAsh has contributed to work by the Contaminated Land Assessment and Remediation Research Centre (CLARRC) on the treatment of mercury and other Persistent Bioaccumulative Toxic pollution, and has developed solutions and supplied products to treat muds from the tunnelling industry, oil industry and the construction industry, and to stabilise sewage sludge, paraffin waste and heavily contaminated canal dredgings.
There are a number of treatment options including in-situ, ex-situ and the new Accelerated Carbonation Technology (ACT).
Recycled Road Arisings
ScotAsh products were used to reinstate part of the historic carriage drive in Finsbury Park, London. The granular surfaced, asphalt road was excavated and the arisings were milled in situ and then stabilised by adding ScotAsh blended pozzolanic and hydraulic material. The rolled stabilised aggregate was then compacted back down, giving a good result with 100% recycled materials – and no heavy lorry movements through the park.
A similar project was conducted at Rainham Landfill site in Essex where a custom blended ScotAsh product was combined with crushed waste aggregates from the landfill site and used to reinstate the approach road.
Recently we have worked with Stabilised Pavements on sustainable road repair projects in Stirlingshire and Dumfriesshire.
Conditioned Fly Ash (PFA)
Overview
ScotAsh supplies two types of conditioned fly ash, or Pulverised Fuel Ash (PFA):
Conditioned fly ash, direct from our silos at ScotAsh and conditioned with water prior to delivery.
Stockpiled fly ash from Fiddlers Ferry Power Station. This material is excavated and then screened prior to dispatch.
Both sources meet the requirements of BS 13055 for Lightweight Aggregates.
Conditioned fly ash 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.
Conditioned fly ash 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.
Furnace Bottom Ash (FBA)
Overview
FBA is the “coarse” ash fraction produced by coal-fired power stations when pulverised fuel is burned at high temperatures and pressures. It has similar chemical properties to PFA, consisting predominantly of oxides of silica, aluminium and iron, but has a sand-like gritty texture.
Uses and Benefits
FBA is used as a lightweight aggregate in the manufacture of building blocks and other products for the construction industry. It can also be used in foamed concrete as a trench fill and as a structural lightweight fill material, such as in embankments on soft or poor ground conditions.
FBA is also popular as a free draining base and growing media in the fairways and greens of golf courses, for example, and in equestrian arenas.
Source: ScotAsh
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