engleski

Recycling of aggregates from construction waste for use in concrete

Recycling of construction waste in some European countries, makes more than 80 % of total construction waste - demolition waste. In this way it is possible to reduce consumption of natural resources and to solve the problem of construction waste disposal on unsupervised disposal sites at the same time. Construction waste or demolition waste can be used as aggregates for concrete, mortar, asphalt or other civil engineering works in road construction depending on material types. It can be either concrete or asphalt crushed materials, but it is generally the mixture of these materials and big quantities of excavated material. Concrete recycling following a process of demolition consists of following steps: selecting waste material ; crushing blocks of concrete ; removal of undesired ingredients ; mixing in with natural aggregate. All other materials built in, such as reinforcement, must be removed and presence of other materials like asphalt, soil, glass, plaster, paper or wood should be avoided. Plants for aggregate recycling are similar to plants for producing of crushed aggregates from natural deposits. Recycling plant can be mobile and situated near structure being demolished or near new structure where recycled aggregates will be used. Alternatively central plant doesn't have to be placed near the structure which is being demolished. Such plant can have much bigger efficiency due to automation of the process. Accordingly large distances to the place where the recycled aggregates are used will be thus compensated. Recycled aggregates should meet all the requirements for the aggregate obtained by processing natural or manufactured materials. Furthermore, concrete made of recycled aggregates can be mixed, transported, placed and compacted in the same way as ordinary concrete. The properties of recycled aggregate and natural aggregate, which may differ, are density, water absorption and contaminants content. These features will be discussed in this paper.

Recycled aggregate; concrete; construction waste; requirements; properties

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