swelliswelling control of forest road bed soil by polymeric materials

soil is known as the base material for many structure, on the other hand, some soils cause problems for some structures such as roads. some types of soils absorb moisture and swell then they may shrink when losing water. the changes of moisture in these soil samples cause changes their volume and pressure to layers of the pavement and eventually leads to destruction of roads. therefore, it is necessary to assess and study methods to improve the swelling properties of these soils. unfortunately no study has been conducted in this field in forest environment yet. in this study the effect of rpp as a polymer stabilization for controlling swelling of forest soils was investigated. compaction tests, swelling potential and swelling pressure on the soil samples treated with different percentages of rpp (0/019, 0/04 and 0/06%) were conducted. in order to test swelling potential and swelling pressures, samples were prepared with optimum moisture determined by compaction test and were compressed by static compaction method and then moved to consolidate apparatus. according to the results of this study, adding of rpp can decrease swelling potential and swelling pressures of soil slightly and to achieve better results the percentage of rpp, should be increased. the results showed that rpp may be an alternative for swelling control of soil in forest roads but economic and technical studies are needed to determine the mechanism for stabilization and evaluating their performance in field conditions.