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• Using PG excites the reactivity of FA and improves the hydration degree of cement. • Mechanical properties and permeability of steam-cured sample are investigated. • Using appropriate amount of PG reduces cost and environmental impact of steam-cured FA mortar. Incorporating proper amount of fly ash (FA) contributes to improve the long-term performance of steam-cured mortar. However, with the introduction of stringent environmental policies, the reserves of high-quality FAs are decreasing and the costs are increasing. In this study, phosphogypsum is used to replace part of FA to produce high-quality prefabricated components, and mechanical properties, water permeability, microstructure and environmental benefits of samples are investigated. The research results show that replacing FA with proper amount of PG can greatly increase mechanical properties of steam-cured FA mortar and improve its water impermeability. When 10% of PG is applied to the steam-cured FA mortar, the 1-d and 28-d compressive strengths of the samples increase by 11% and 5.37%, respectively, relative to the control mortar. The results of microstructure characterization show that this is due to the generation of swelling products and the increase of the reaction degree of FA. When PG and steam curing are applied in combination, FA is severely corroded and a gel phase product is generated, which contributes to increase the strength of specimen. In addition, using appropriate amount of PG also brings obvious economic and environmental benefits for prefabricated components. [ABSTRACT FROM AUTHOR]

• The iron-copper tailings are recycled in prefabricated elements. • The mechanical properties and durability of steam-cured mortars are investigated. • Adding an appropriate amount of tailings is beneficial to improve the performance of steam-cured mortar. With the development of construction industrialization, the use of steam curing to produce precast concrete is widely used. In order to recycle long-term stacked tailings waste, iron-copper tailings (ICT) waste is comprehensively utilized in steam-cured mortar (SCM). The effect of ICT substitution level on the mechanics and durability of steam-cured mortars is investigated in this study. The research results show that the use of appropriate ICT instead of river sand in the production of mortar is beneficial to the enhancement of the mechanics and durability of the mortar. When the replacement level of ICT is 10%, the 1-d and 28-d compressive strength of SCM are increased by 1.09% and 7.27% respectively compared with plain mortar. SCM mixed with 10–20% ICT has lower permeability compared to plain samples, and further increasing the substitution level of ICT is not benefit the development of mortar durability. Since ICT has better conductivity compared to river sand, it makes the resistivity of SCM decrease with the increase of ICT content. Microstructural studies show that the addition of a small amount of ICT reduces the porosity of SCM and refines its pore structure. Meanwhile, the ICT and cement matrix exhibits a more dense ITZ than the river sand and cement matrix. Recycling of ICT also shows better economic and environmental benefits in SCM. This study provides a theoretical basis for recycling composite tailings waste in prefabricated components. [ABSTRACT FROM AUTHOR]

• Detailed nonlinear characteristics of shear stiffness for warp-knitted NCF composites under shear-tension coupling loading were discussed. • Shear-tension coupling effects on stiffness nonlinearities were investigated. • A new method for determination of shear stiffness was proposed, and its feasibility was verified by FEA simulation using UMAT. • Differences in shear stiffness and micro-deformation mechanisms between NCF and PWF composites were revealed. In order to reveal shear deformation mechanisms of architectural non-crimp fabric (NCF) composites, detailed shear stiffness-nonlinearities for a typical coated warp-knitted NCF composite under shear-tension coupling loading were studied from experimental investigation and FEA models. Shear-tension coupling effects on shear stiffness of the NCF composite were investigated for different stress states. Its shear stiffness shows significant nonlinear characteristics which are highly tensile stress level (TSL) related, and therefore a critical TSL value was obtained for the studied material. Moreover, a new method for determination of shear stiffness was proposed, and its feasibility was verified by FEA simulation using UMAT. In addition, differences in shear stiffness and micro-deformation mechanisms between NCF and plain-woven fabric (PWF) composites were analyzed specifically. Apparently, the yarn-to-yarn compression on the yarns could contribute to the different stiffness variations between these two composites. [ABSTRACT FROM AUTHOR]