عنوان مقاله [English]
For years, many researchers and experts particularly in Iran have been trying to find suitable matters as an alternative to bituminous mulch for fixing sand dune system or slack soil bed. One of the advantages of bituminous mulch is the plasticity and elasticity behavior while fixing sand but many researchers believe that it is environmentally harmful for many soil inhibitors. Currently most of the native mulches produced by different companies after spraying on sand dune will soon be degraded and broken, thus its performance for stabilizing sand is decreased drastically during time past. Since sand materials are physically classified as none plastic behavior, it is difficult to mix mulches with sand and then measure the degree of plasticity. In this research, a new and simple method is introduced to identify the plasticity index for different mulches used in sand dune stabilization or slack soil bed using Casagrand device. In this method, firstly a clayey or a heavy textured soil is selected as a control and the degree of its plasticity index is measured with distilled water. Secondly, the same soil is mixed with the selected mulch instead of distilled water and then same procedure is followed to measure the plasticity index of mixture using standard method of Casagrand. Finally, subtracting the plasticity index of the control soil from the total plasticity index of the mixture resulted in the selected –mulches plasticity index as mentioned in the article.