Study about the rehydration of phosphogypsum hemihydrate in tropical soil mixtures

Abstract

ABSTRACT The objective of this paper is to verify the occurrence of phosphogypsum hemihydrate (PG-HH) rehydration and its influence on the mechanical behaviour in tropical soil mixtures. The studies were carried out in mixtures with lateritic clay, PG and Portland cement. Were carried out microstructural and mineralogical analyses with scanning electron microscopy and X-ray diffraction experiments, compaction tests at different setting times and unconfined compressive strength tests on saturated samples subjected to weathering. This study showed that PG-HH can rehydrate when it is in contact with water. This fact changes its crystals’ shape and impacts the mechanical behaviour of tropical soil mixtures. Saturated samples exposed to weathering presented strength reduction. However, the strength of mixtures with PG-HH, even when rehydrated, is superior to the strength of mixtures with PG-DH. The incorporation of PG-HH in mixtures with tropical soil and cement in geotechnical works is possible despite its rehydration.