Synthesis and characterization of fiber-reinforced lightweight foamed phosphogypsum-based composite

Abstract

A foamed phosphogypsum-based composite (FPGC) was synthesized in this study via chemical foaming and the effect of hydrogen peroxide (H2O2) (0.5% to 2.5%) on its properties was investigated. With the increasing dosage of H2O2, more foamed pores were produced, causing a decline in the mechanical strength and water resistance of mixtures. Nonetheless, the increased pores resulted in an improvement in thermal insulation and acoustic absorption. Fiber addition resulted in slight enhancement in the acoustic absorption and thermal conductivity but significantly improved the mechanical strength and water resistance of fiber-reinforced FPGC, particularly polyvinyl alcohol (PVA) fiber. The calcium stearate (CS) (5% to 25%) as foam stabilizer was also incorporated to ascertain its effect on the properties of FPGC. CS content exceeding 15% had a positive effect on the properties of fiber-reinforced FPGC. Finally, the fiber-reinforced FPGC with 1% PVA fiber, 1.5% H2O2, and 20% CS attained a bulk density of 826 kg/m3, compressive strength of 5.08 MPa, softening coefficient of 0.69, and improved sound absorption and thermal conductivity of 0.483, and 0.221 W/m·K, respectively. This study presents a promising approach for the utilization of phosphogypsum (PG), and further works can be explored to evaluate the long-term performance and durability of FPGC in various environmental conditions.