A new eco-friendly concrete made of high content phosphogypsum based aggregates and binder: Mechanical properties and environmental benefits

Waste phosphogypsum (PG) has been proved recyclable in producing qualified aggregate and binder for concrete, with a substitution rate of above 70% in aggregate and 40% in binder. Therefore, it is feasible to use phosphogypsum with high content as recyclable aggregate and binder. This paper provides a detailed description of high-content phosphogypsum-based concrete (HPGC) preparation process, together with evaluation of mechanical properties, impurity stability, and radioactivity of the concrete. The prepared HPGC is heavier than typical lightweight concrete, with reduced mechanical properties and qualified leaching performance. The compressive strength of the concrete prepared in this experiment at 28d was generally in the range of 18 MPa–40 MPa. Upon significant drop in compressive strength, critical PG content in coarse aggregate is around 80%, while the content in binder is about 60%. The concrete makes a good solidification of waste PG, with release of hazardous matters acceptable according to local building codes. Featuring a substitution rate of above 800 kg/m3, the PG concrete technology would find large-scale applications in recycling massive phosphogypsum waste.