Abstract
After investigating the characteristics of aggregate shape, the shrinkage behavior of aggregates was studied experimentally, in relation to the pF of soil moisture. The main results obtained are as follows:
(1) Among the factors of aggregate shape (width, length and height), there existed a constant relation (Table 1) and the aggregate volume was also investigated (Table 2). Consequently, it was shown that aggregates maintain a similarity in form, during the process of shrinkage.
(2) At the first stage in the drying of aggregates, the rate of drying decreased as the aggregates increased in size (Fig.4).
(3) The relationship between aggregate volume and pF values, in the process of shrinkage, was shown approximately as two straight lines (Fig. 5).
(4) In the range of pF<4. 2, the shrinkage of aggregates was restrained as the aggregate increased in size. In the range of pF≤4. 2, the shrinkage of aggregates showed an opposite inclination (Fig.6).
The aspects of the aggregate shrinkage according as sizes, were bounded by the diameter, about 10 mm (Fig.6).
(5) The characteristics of the above-mentioned shrinkage behavior of aggregates, were explained by the hierarchy concept in aggregation.
