Role of curing temperature in progress of lime-soil reactions

An expansive black cotton soil was used to assess if ambient temperature influences the progress of lime-soil reactions. Lime-soil mixes containing lime additions above the Lime Modification Optimum (or Initial Consumption of Lime value) of the expansive black cotton soil was cured for periods ranging from 1 hour to 400 days at 25 degrees C. The curing temperature of 25 degrees C is representative of mean temperatures occurring in semi-arid regions of Karnataka, India. The in situ progress of lime treatment was monitored by the use of electrical conductivity and pH measurements. The trend of decrease in conductivity and pH of the 4 and 7% lime-soil mixes suggested that pozzolanic activity commenced after 1 day of curing at 25 degrees C. Comparatively, an earlier study by other researchers had reported that pozzolanic activity does not commence before 7 days of curing at 11.5 degrees C for lime additions above the Lime Modification Optimum value of swelling clay. Combining the results of studies at 25 degrees C and 11.5 degrees C, it appears that higher ambient temperatures do accelerate the progress of lime-soil reactions.