Effect of Drying Temperature and Rewetting on the Engineering Properties of Marine Clay

Abstract

This paper presents an experimental investigation on the influence of drying marine clay at different temperatures of 27 °C (room temperature air drying), 40 °C, 60 °C, 80 °C, 100 °C and 150 °C (oven drying) on its geotechnical properties. The same soil dried at various temperatures is then rewetted for 7 and 28 days and examined for its variation in the engineering properties. Investigation includes gradation analysis, consistency limits, compaction characteristics, shear strength properties and California bearing ratio. For the level of significance on the drying temperature variation, one-way analysis of variance (ANOVA) is performed using the Microsoft Excel software. Laboratory test results showed a decrease in clay size fractions and an increase in silt and sand size particles with increased drying temperature. Liquid limit and plasticity index decrease with an increase in drying temperature till 100 °C. Improved compaction characteristics, unconfined compressive strength, long-term stress-strain behaviour and California bearing ratio were found upon drying the soil at 100 °C. These results are useful in sample preparation prior to testing, also in specific geotechnical applications of underground storage of radioactive waste, an alternative to crushed rocks in pavement and ground source. Rewetting of the dried soil did not show much variation in gradation, index and compaction properties which are compared with the same properties of soil tested immediately.