Fine inorganic waste materials (FIWM) represent one of the greatest environmental strains. They are the result of solid fuel incineration processes (heating plants and coal power plants), quarrying and natural stone treatment, or grinding of concrete, glass, etc.
FIWM are a by-product of various technological processes. Based on their purpose, their further possible use and the kind of input materials, FIWM are mostly materials of a variable mineralogical and chemical composition and they have different mechanical-physical qualities. Opinions about the possible application of FIWM in construction vary.
The use of fine particles (d≤0,063mm) in the production of building materials, especially in the production of concrete, is limited due to technological reasons. Increase of fine particles in concrete production results in the increase of binder as well as water, which is an undesirable effect for a number of reasons. Inorganic waste materials are routinely used in the production of synthetic aggregate, e.g. FOMAPOR®, which utilizes also waste dust left over from the extraction and processing of natural stone.
The porous aggregate FOMAPOR® is made of the above mentioned waste dust. The aggregate comprises a calculated minimal ratio of FIWM to dry components necessary to produce the aggregate whilst keeping the lowest possible bulk density and the highest resistance to crushing (strength). Such parameters offer the potential producers of synthetic aggregate a wide utilization of the product whilst keeping the manufacturing costs low. The production process requires the temperature of 20 °C.
My experiments prove that it is possible to use a variety of waste dust for the production of the synthetic aggregate FOMAPOR® even when the ratio of dust to dry components is high. Setting the waste dust parameters aside, we can see that its presence in the aggregate has a significant impact on the monitored parametres, especially on the resistance to crushing (strength). Using waste dust is inexpensive as there are no technologies needed to process it and no additional costs involved.
Waste dust, which is a by-product of various kinds of stone processing, can be directly and extensively used to produce new types of building materials – e.g. the synthetic aggregate FOMAPOR®. The technical specifications of synthetic aggregate allow for a direct and effective utilization of the aggregate as backfill material or levelling material, and it can also be used to produce lightweight building constructions and lightweight concrete. Given the abundant supply of waste dust, the parameters of the synthetic aggregate FOMAPOR® can be freely modified to change its characteristics as needed and to fit the needs of the construction materials market. The producer of the synthetic aggregate FOMAPOR® will further cut costs by reducing the amount of waste dust for disposal and thus lowering the cost of disposal.
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© 2020 Ing. Václav Vachuška
Photo: Ing. Václav Vachuška