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In this study, the viability to utilize the residue, obtained from a sewage sludge (SS) and biomass combustion/gasification plant (GR), in cement-based materials was analysed. Two pozzolanic materials were selected to make GR more recyclable: metakaolin (MK) and spent catalyst waste (Z), received from fluidized-bed catalytic cracking process. Functional and environmental properties of standard cement pastes and mortars as well as binary and ternary combinations of GR with MK and Z were assessed. Results showed that enhanced mechanical strength, reduced water absorption and heavy metals release were obtained for compositions when GR was combined with one of the pozzolanic material MK or Z. Microstructural analysis revealed that due to addition of pozzolan the surface of GR particles was covered by a layer of hydration products. In particular, the use of MK led to the formation of more porous layer whereas application of Z tends to the formation of a dense-layered structure on the surface of GR. N sorption results showed that contrary to MK the incorporation of Z into cement composition with GR reduced volume of small capillary pores, and therefore, resulted in lower water absorption and heavy metals release. The obtained results suggest that the application of Z appears to be advantageous pozzolan for the stabilization of SS-biomass gasification residue in cement-based materials.

Complex binder reinforced with microfibre produced from waste catalyst was investigated. Influence of 1, 3 and 5 % of fibre as well as 5 % of microsilica on the mechanical strength of complex binder after thermal treatment at 600, 800 and 1000 °C temperature was analyzed. According to the experimental results reinforcement with 1 % of fibre had advantage on mechanical strength of complex binder up to 800 °C, meanwhile 5 % of fibre resulted in the lowest values of strength in all firing temperature range. The strength of dry samples was improved with microsilica incorporation. But above 800 °C temperature cold crushing strength as well as thermal shrinkage of binder reinforced with fibre and microsilica was lower in comparison with ordinary complex binder at 1000 °C.

http://dx.doi.org/10.5755/j01.ms.17.1.253