LIME AS AN ALTERNATE BINDER FOR SUSTAINABILITY

Abstract

Cement mortars gradually replaced the use of lime mortars for construction after the development of Portland cement in the late nineteenth century. Because of the negative impact of cement on heritage structures, lime mortar applications for historic building repair have been revived. Kankar lime is an impure form of limestone (CaCO3) and is a natural hydraulic lime found in alluvial deposits and is considered as suitable material for conservation and restoration of heritage structures. In this study, Kankar lime has been used as a binder along with surkhi and its physical and mechanical properties are determined. The curing condition for lime mortar has been standardized and rate of loading for better compressive strength has been standardized. This study also aims at determining optimum burning temperature for calcination of kankar lime. Kankar lime was heated at elevated temperatures (8000C, 9000C, 10000C) and chemical composition was determined by different scientific tests like SEM, XRD, XRF to assure the conversion of kankar lime to quick lime (CaO). The calcination percentage was determined by the LOI method proposed by researchers. The percentage calcination due to increase in temperature (8000C – 10000C) was found to be more significant than the percentage calcination due to increase in dwelling time (6 hr. – 9 hr. ) at a particular temperature (say 8000C). The effect of particle sizes ( < 4 mm, 4-20 mm, >20 mm ) on calcination efficiency was also evaluated. In addition, Activation energy was also calculated by thermogravimetric analysis (TGA) technique using equation given by Coats Redfern.