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This research reports the investigations of threshold reactivity limit of blends of pegmatite with different calcined clays as well as the influence of calcined clay source on the geopolymerization kinetic, microstructural, and physicomechanical properties of feldspathic mineral-based inorganic polymer composites. These composites were designed from 85 to 94 wt% of the solid solution of pegmatite and calcined clay. The three-point flexural and compressive strengths, porosity, and microstructure as well as heat evolution rate of geopolymerization reactions of resulting composites were affected by the type of calcined clay. The four calcined clays provided the highest mechanical properties of the composites when added in the range of 12-15 wt%. Specifically, the values of flexural and compressive strengths ranged from 32 to 34 MPa and 101 to 105 MPa, respectively, for geopolymer composites with 15 wt% of metakolin added, while they ranged from 38 to 42 MPa and 106 to 107 MPa with 12 wt% of meta-hallosyte added. The polycondensation/polymerization process of calcined clay developed sufficient amounts of N-A-S-H and polysialate geopolymer to cover the incongruently dissolved fine particles of pegmatite. The resulting microstructure was dense and compact with the lower cumulative pore volume at about 91 mm3/g. It was concluded that designing the pegmatite/clay-based geopolymer composites with high mechanical strengths and low porosity resulted in sustainable, low energy consumption and environmental-friendly materials for civil engineering. [ABSTRACT FROM AUTHOR]

Ceramic tile manufacturing is a highly energy-intensive process. Concerns about carbon emissions and energy costs make energy management crucial for this sector, which holds a leading role in Italian industry. The paper discusses the energetic and environmental performance of cogeneration (CHP) in the ceramic industry, where prime mover exhaust heat is supplied to a spray-dryer system, contributing to the satisfaction of the thermal demand and decreasing natural gas consumption. A thermodynamic model of a dryer unit, validated against real data, has been set-up to provide a detailed representation of the thermal fluxes involved in the process. Then, the thermal integration with two types of CHP prime movers of similar electric size (4 MW) is investigated. Energetic results show that the gas turbine can contribute up to 81% of dryer thermal consumption, whilst internal combustion engine contribution is limited to 26%. A methodology was ad-hoc defined for the environmental assessment of CHP, accounting for global (CO2) and local (CO and NOX) emissions. Results confirm that CHP units guarantee reduction of CO2 and NOX compared to separate generation, with maximum values equal to 81 g/kWhth and 173 mg/kWhth, respectively; CO emission is decreased only in the case of gas turbine operation, with savings equal to 185 mg/kWhth. [ABSTRACT FROM AUTHOR]

Air lime mortars with addition of two types of sesame cooking oil were synthesized and cured in two different conditions: laboratory and natural climatic conditions of the Pasargadae and Persepolis World Heritage Sites. For the mortars cured in the laboratory, addition of oils in the mortar induced hydrophobic effects, but it adversely affected on permeability values and carbonation rates. However, the air lime mortars cured in the site conditions demonstrated increment in their hydrophobicity and superficial durability without retarding their setting time and adverse effects on their calcium carbonate formation values, due to various climatic parameters existing in natural outdoor conditions. [ABSTRACT FROM AUTHOR]