Acid Resistance of Mortar Using Ferronickel Slag (FNS) Aggregate and Ground FNS as Supplementary Cementitious Material
Ashish Kumer Saha and Prabir Kumar Sarker
Appears on pages(s):
calcium-silicate hydrate; capillary pores; cementitious materials; durability; ettringite; fly ash; gypsum; manufactured sand; microscopic
This study evaluates the acid resistance of cement mortar using granulated ferronickel slag (FNS) as fine aggregate and fly ash or ground FNS (GFNS) as a supplementary cementitious material (SCM). The deterioration was evaluated by visual inspection, and changes of mass and strength after immersion in 1% sulfuric acid solution for up to 180 days. Acid resistance was marginally reduced when 50% volume of sand was replaced by FNS. While the control specimens suffered significant spalling and strength loss, the use of fly ash or GFNS considerably reduced the deterioration. This is attributed to the formation of a protective zone and densification of microstructure by the pozzolanic reaction, as confirmed by strength activity index, permeable voids, thermogravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Overall, the specimens with FNS aggregate and GFNS or fly ash showed less deterioration than the control specimens after
prolonged acid exposure.