Effect of drying and wetting on shrinkage and changes in physical properties of peats of Central Kalimantan, Indonesia

摘要

A study to elucidate the effect of drying on shrinkage and changes in physical properties of fibric, hemic and sapric peats was carried out in a laboratory. Undisturbed peats collected from Central Kalimantan were dried for 60 days to reach 25%, 35%, 45%, 55%, 65%, and 75% of the maximum water holding capacity. After drying, the remaining volume of the peats was measured; the peats were then soaked in water for 7 days. Reversibility, coefficient of linear extensibility, bulk density, water holding capacity, porosity, pore size distribution, wax content and volume of the peats were then determined. The results showed that drying followed by soaking of the peats in water reduced the volume of the peats. However, the drying and wetting treatments did notsignificantly affect the reversible properties of the peats. Shrinkage reduced porosity, number of 30-300 mm pore size and maximum water holding capacity of the peats. The reduction of water holding capacity was not due to the coverage of peat particle with resin (wax) material that protected the peats from water absorption during soaking, but it was due to the decrease in porosity and changes in pore-size distribution of the peats.