Morocco produces annually large quantities of phosphogypsum(PG),which permanent stacking rises technical and environmental constraints.However,the valorization of this coproduct in civil engineering and especially in ...Morocco produces annually large quantities of phosphogypsum(PG),which permanent stacking rises technical and environmental constraints.However,the valorization of this coproduct in civil engineering and especially in roads building,is a promising solution within a circular economy frame.A first experimental one-kilometer-long pilot,incorporating four different PG based formulations with a 7%cement addition,built at Safi in 2017,allowed positive mechanical assessment(by deflector)and environmental one(by leaching test).In order to further evaluate PG use as road material,our experimental approach focuses here on optimizing material mixtures-made of phosphogypsum(maximum content desired)treated with cement(to be minimized so as to reduce the cost)and sand or steel slag as granular corrector-to meet mechanical requirements of a road base material.We first identified and characterized phosphogypsum produced at the Jorf Lasfar plant and other materials used.Design of experiment is used for modeling desired physical and mechanical responses and to establish domains meeting the required criteria for using the mixture material either as road subgrade layer or foundation layer.In addition,through a parametric study,we evaluated the effects of traffic level,soil bearing capacity and mechanical performance of treated phosphogypsum mixtures on pavement design for three different pavement structures(mixed,reverse and structure with treated sub-base)and determined that the best to adopt for maximizing PG recycling is the pavement structure with subbase treated with hydraulic binder.展开更多
文摘Morocco produces annually large quantities of phosphogypsum(PG),which permanent stacking rises technical and environmental constraints.However,the valorization of this coproduct in civil engineering and especially in roads building,is a promising solution within a circular economy frame.A first experimental one-kilometer-long pilot,incorporating four different PG based formulations with a 7%cement addition,built at Safi in 2017,allowed positive mechanical assessment(by deflector)and environmental one(by leaching test).In order to further evaluate PG use as road material,our experimental approach focuses here on optimizing material mixtures-made of phosphogypsum(maximum content desired)treated with cement(to be minimized so as to reduce the cost)and sand or steel slag as granular corrector-to meet mechanical requirements of a road base material.We first identified and characterized phosphogypsum produced at the Jorf Lasfar plant and other materials used.Design of experiment is used for modeling desired physical and mechanical responses and to establish domains meeting the required criteria for using the mixture material either as road subgrade layer or foundation layer.In addition,through a parametric study,we evaluated the effects of traffic level,soil bearing capacity and mechanical performance of treated phosphogypsum mixtures on pavement design for three different pavement structures(mixed,reverse and structure with treated sub-base)and determined that the best to adopt for maximizing PG recycling is the pavement structure with subbase treated with hydraulic binder.
