Effect of drying technique on pore structure characteristics of fine-grained geomaterials

Abstract

The fundamental behaviour of fine-grained geomaterials compacted over a range of moisture content is strongly influenced by the resulting porosity and pore size distribution (PSD) characteristics. The majority of pertinent studies have employed mercury intrusion porosimetry (MIP) for determining these properties. Since the PSD analysis using MIP technique demands moisture free specimen, it is necessary to select an appropriate sample drying technique that minimises the alteration of soil fabric during sample preparation. In view of this, the present study evaluated the influence of various drying techniques, such as oven-drying, solvent-replacement and freeze-drying, up on the soil fabric in terms of its PSD characteristics. Further, the study investigated the role of placement moisture content on the modifications of soil fabric when soil specimens are compacted over a range of compaction states, using scanning electron microscopy. Based on the obtained results, it is demonstrated that the sample drying using lyophilisation technique is efficacious.