Lightweight aggregate systems
Heating clay or shale in a rotary kiln to a temperature that causes the material to expand or bloat makes conventional lightweight aggregate (LWA).
Expanded shale and clay (ES&C) aggregates also called low-density aggregates have been used successfully around the world in more than 50 different types of applications. Structural lightweight concretes are typically produced with expanded shales, clays, slates and slag. They can also be made with pumice or scoria, which are naturally occurring volcanic aggregates. Moderate strength concretes fall somewhere in between low-density and structural lightweight concrete. Lightweight aggregate is used not only for its lighter weight but also for its superior sound abatement, seismic performance, fire resistance, insulation and geotechnical properties.
LW Aggregate kilns are suitable for:
- Masonry (construction block, precast concrete, lightweight structural concrete, roof tile)
- Highways & Roads (asphalt chips, de-icing aggregate, geotechnical fill)
- Horticulture (drainage and aeration, soil conditioner, secorative, 100 percent inert, inorganic)
- (Used heavily on athletic field, water filtration)
- New uses everyday
Main benefits of Metso systems are:
- Year of experience will all types of rotary kilns
- Capable of installation anywhere in world
- True understanding of process conditions
- In house engineering for custom fit applications
As a strong and lower density material, lightweight aggregate is used in pre-cast concrete to reduce the load by 25 – 35% in bridges and high-rise buildings. It is used in concrete blocks to reduce their weight and increase worker productivity. Concrete made with lw aggregate also has higher strain capacity and lower shrinkage. Different ranges of regular and lw aggregates are mixed depending on the specifications required.
Used as a geotechnical fill it posses perfect characteristics to reduce dead loads and keep from soil thrusting while at the same time increasing drainage. It is inert and chemically stable so it can be used in landfills.
Metso supplies lightweight aggregate systems using both naturally occurring clays and waste materials as feedstock. A commercial scale plant has been built using coal fired boiler ash and municipal sludge.
We've also done tests on a variety of other wastes such as granite dust, dredge sludge and pulp mill sludge.
More information about lightweight aggregates
