Investigating the Effect of Superabsorbent on Compaction Behavior of Soil using Confined Compression Test

Agricultural soils improvement and amendment has an inevitable importance. The implementation of new tillage methods and using some additives such as superabsorbent, in order to optimally use of water in rainfed farms to increase the yield of crops, has particular importance in this relation. Superabsorbent polymers are organic compounds that are able to absorb water several times of their own volume or weight without changing their physical structure. The purpose of this research is to investigate pre-compaction stress as a measure of resistance of soil compaction in the presence of superabsorbent polymers. In this research, the pre-compaction stress was determined using the confined compression test (CCT). The factorial experiment was carried out in the form of a completely random design with three replications on the samples with humidity of 15% and 10% and density of 1.4, 1.5 and 1.6 at five levels of 0, 1, 2, 3 and 4 grams of polymer per kilogram of soil. The results of the tests showed that with the increase in the amount of superabsorbent, pre-compaction stress and compaction index increased. The maximum effective amount of superabsorbent is three percent by weight, which creates moisture suitable for agricultural products. In both humidity of 10 and 15%, the highest pre-compaction stress was equal to 2.8.