A phosphogypsum-based road material with enhanced mechanical properties for sustainable environmental remediation

An integrated approach for sustainable use of phosphogypsum (PG) byproducts as road materials was developed. For the purpose of this study, several formulations of PG-based material have been performed to evaluate its potential application for road base layers. Physico-chemical properties, mechanical strengths and environmental aspects were simultaneously addressed. Both dynamic and batch leaching tests have been carried out to properly evaluate the leaching behavior of the prepared road mixture versus binder type and age of phosphogysum used. Commonly used geotechnical tests, including compressive strength, tensile strength as well as Young's modulus have been carried out on the prepared specimen. Strength development at different curing times was studied and compared to conventional road base materials. The obtained results indicated that the 28- and 360-days strengths reached 2200 and 3500 kPa, respectively. Cement stabilized material showed higher strength values (both early age and final compressive strength) than conventional road base materials. Those encouraging properties were confirmed by X-ray diffraction and scanning electron microscope analyses. Further study focused on potentially toxic elements released from both original PG and newly prepared formulations. It was found that almost all contaminants studied were significantly immobilized in the formulations with high pH values. This may offer an efficient waste disposal concomitantly with reducing the demand for natural aggregates, therefore a significant gain in life cycle impacts and costs. This is a low cost and handy tool for sustainable environmental remediation via the use of byproducts that have no potential threat of contaminants leaching.

Automated summary

An integrated approach for sustainable use of phosphogypsum byproducts as road materials has been developed, focusing on evaluating the potential application of phosphogypsum-based material for road base layers. The study addressed physico-chemical properties, mechanical strengths, and environmental aspects, indicating that cement-stabilized material showed higher strength values and potential environmental remediation benefits.