Performance Study of Environmentally Friendly Construction Gypsum Prepared from Recycled Phosphogypsum and Waste Glass Fibers

Phosphogypsum, as a by-product of the wet process phosphoric acid industry, is in urgent need of resource utilization due to the environmental risks caused by its massive accumulation; at the same time, the green recycling of used wind turbine blades (including glass fibers) is also a hotspot of global concern.In this study, a synergistic regenerative preparation method of environmentally friendly construction gypsum is proposed using phosphogypsum and recycled glass fibers from waste wind turbine blades as raw materials.The matrix material was prepared by mixing physically treated phosphorus building gypsum with natural building gypsum (8:2 ratio) and blended with recycled glass fibers of different lengths (0-5, 5-10, 10-15, 15-20 mm) and blending amounts (1.0%, 1.5%, 2.0%, 2.5%), and the effect on the performance of the gypsum was systematically analyzed.The results showed that the incorporation of glass fibers significantly reduced the slurry extension (maximum drop of 30 mm) and setting time (final setting time shortened by 115 s), but significantly improved the mechanical properties.The flexural strength reached 5.6 MPa when 15-20 mm glass fibers (2.0% doping) were doped, which was 51.35% higher than that of the blank control group; the compressive strength was raised to 11.3 MPa (24.17% higher) when 10-15 mm fibers (2.5% doping) were doped.The softening coefficient reached 0.67 at 15-20 mm fiber (dosing 1.5%), an enhancement of 32.37%.The microstructure shows that the glass fibers fill the pores inhibit crack extension through the bridging effect, and present a composite damage mode of fiber fracture and matrix debonding.This study provides a new way for the efficient synergistic utilization of phosphogypsum and waste wind turbine blades, with both environmental benefits and engineering application potential.