Construction and Building Materials, cilt.440, 2024 (SCI-Expanded)
In this study, polyester woven fabric reinforced Portland cement and α hemihydrate gypsum-based multi-layer composites were prepared with and without calcined diatomite substitution. Mechanical performance parameters, unit volume weights and CO2 emissions of these composites were determined. The optimum number of polyester woven fabric layers in terms of tensile performance was determined as three layers in Portland cement-based composites with calcined diatomite substitution. This number was found to be four layers in α hemihydrate gypsum-based composites with calcined diatomite substitution. Calcined diatomite substitution improved the woven fabric-matrix interface by facilitating the formation of the pozzolanic reaction in the case of Portland cement series, while no reaction developed in the gypsum series, resulting in a relatively poor woven fabric-matrix interface. However, calcined diatomite has provided lightweight in gypsum composites by exhibiting unit volume weight values as low as 1467 kg/m3 due to its micro-porous structure. This situation has been characterized through microstructure examinations. The increase in the fiber/matrix volume ratio improved the tensile strength from 3.18 MPa to 6.79 MPa, peak toughness from 210 kJ/m3 to 489 kJ/m3 and tensile ductility from 11.86 % to 14.77 % in the case of α hemihydrate gypsum-based and diatomite-substituted series. At three and four layers of fabric reinforcement, the tensile parameters of α hemihydrate gypsum diatomite-substituted series reached similar values to those of Portland cement series. The diatomite-substituted gypsum series caused a 50 % decrease in CO2 emission compared to Portland cement series. It has been demonstrated that reinforced polyester woven fabric composite materials prepared with α hemihydrate gypsum incorporating diatomite are ideal for the production of lightweight and moderate strength structural elements if the fiber/matrix volume ratio (fabric layer) is optimized. Gypsum-based series are gaining prominence as environmentally friendly alternative materials with low CO2 emission values in applications such as gypsum board, facade cladding and architectural restoration.