Effectiveness of technogenic waste usage in products of building ceramics and expanded clay concrete

In this paper the influence of the burned and the unburned mullite wool waste on the properties of ceramics and expanded clay concrete has been analysed. It has been determined, that this waste could be successfully used in the manufacture of expanded clay concrete and wall ceramic products. Increasing the quantity of mullite wool in the mix of expanded clay concrete, the forecasted frost resistance decreased and the water absorption increased. Products without waste and those having 10% of the waste have similar compressive strength. The performed research has shown that the unburned mullite wool waste is the active micro filler, however it does not decrease the quantity of portlandite formed, but performs a framing function. Modifying the composition of ceramics with the burned mullite wool waste, the density of samples decreased, but the parameters of water absorption and compressive strength increased. To receive stronger ceramic products, 15% of the burned mullite wool waste should be added, then the compressive strength is 23 MPa, however the forecasted frost resistance of such ceramic body would be only 65 cycles. The highest frost resistance (about 200 cycles) of ceramic samples was received applying 5% of the waste additive, then compressive strength is about 16 MPa. The unburned mullite wool waste decreases the frost resistance and density of expanded clay lightweight concrete samples, and increases the water absorption. Replacing 10% of cement with the unburned mullite wool waste almost does not change the compressive strength and density, but decrease frost resistance 36% and increase water absorption 4%.

► The optimum quantity of the waste in the production of frost resistant ceramics is 5%.
► To receive stronger ceramic products, 15% of the burned mullite wool waste should be added.
► The mullite wool waste decreases the frost resistance and density of expanded clay concrete.
► Replacing 10% of cement with the mullite wool waste almost does not change the compressive strength.