Abstract :
|
Compacted waste foundry sand an industrial waste from metal foundries was treated with cement kiln dust (CKD) an industrial waste from cement producing factories and assessed in order determine its soil-water characteristics curves (SWCCs). SWCC data were used to determine the fitting parameters to two most commonly used soil-water retention models, the Brooks-Corey and van Genuchten models. These models also formed the basis for the prediction of volumetric water content (?) for the soil specimens. 0, 4, 8 and 12% CKD by dry weight of soil were prepared at three energy levels (British standard light, West African standard and British standard heavy) at -2, 0, +2% of the optimum water content. The shape of the SWCC depends on the soil structure, compaction water content and comp-active effort. Compaction at higher compaction water content or with greater comp-active effort results in larger air entry pressure. Changes in the shape of the SWCC are consistent with changes in pore size that occur by varying compaction conditions (compaction energy, molding water content). These changes in the SWCC are also reflected in the van Genuchten (VG) and Brooks-Corey (BC) parameters, VG’s n showed a decrease in value from the dry side to the wet side of optimum moisture content, this trend indicates that a decrease in the uniformity of pore sizes occurs as molding water content increases from the dry to the wet side of optimum. Variation of VG’s alpha (a) with molding water content did not produce any clear trend BC fitting parameters lamda (?) did not produce clear trend with variation in molding water content. BC air entry pressure (?a) increases with increasing of compacted molding water content because specimens on the dry side of optimum normally contain a bimodal pore size distribution, with the larger macro pores existing between clods that are not remolded during compaction, in contrast to soil compacted wet of optimum water content. The statistical analysis of the goo
|