MICROSTRUCTURAL PROPERTIES OF COLUMN CONSOLIDATED PASTE BACKFILL

The objective of this study is to characterize the microstructural properties of cemented paste backfill (CPB) after its self-weight consolidation in columns. To reach this objective, three self-weight consolidation column tests that have each 3 m height were carried out on in situ CPB samples at Louvicourt mine’s backfill plant. These columns simulate three realistic drainage scenarios such as fully drained (FD), half-drained (HD) and undrained (UD) columns. After a 90-day curing time, 20 core samples were taken from each consolidated CPB column and subjected to uniaxial compression tests followed by mercury intrusion porosimetry (MIP) tests and BET (Brunauer-Emmett-Teller) specific surface analysis. Results showed that the MIP total porosity and the specific surface area data of CPB materials are well correlated to the uniaxial compressive strength values. Maximum strength (2.9 MPa) was associated with the completely drained CPB which usually has finer pores, a lower total porosity and a relatively higher specific surface area. This correlation is appreciably different between the bottom and the top of each column consolidated backfill material. RÉSUMÉ L’objectif de cette étude est de caractériser les propriétés microstructurales des remblais en pâtes cimentés après leur consolidation sous leur poids propre en colonne. Pour atteindre cet objectif, trois colonnes de 3 m de hauteur ont ét