Effects of freeze-thaw cycles on consistency limits of soils amended with diatomite

The changes in the structure of soil particles configurations due to freeze-thaw (FT) have great effects on the physical, mechanical, chemical, and biological properties of soil. Variability of temperature and rainfall due to climate change may lead to increased FT cycles which will strongly affect soil properties. Therefore, development of strategies for reducing the negative effects of FT on soil properties should be investigated. To the best of our knowledge, this study is the first to investigate the effects of FT cycles on consistency limits of soils amended with diatomite. In this study, we evaluated the effects of diatomite applications (0, 10, 20 and 30 %, v/v) on the liquid limit (LL), plastic limit (PL), plasticity index (PI), shrinkage limit (SL), and friability index (FI) of soils with different textures subjected to FT cycles for 0, 3, 6 and 9 times. While LL, PL and FI decreased with subsequent cycles of freeze-thaw, diatomite applications in all FT cycles and soils significantly increased these parameters. In general, the effectiveness of diatomite on these parameters increased with the increases in application doses and the highest values were obtained at 30 % DE treatments across soils. Freeze-thaw cycles resulted in an irregular increases or decreases on PI and SL values of the soils for all cycles tested. Results obtained in this study have clearly indicated that diatomite application is an effective way to protect and/or to increase the negative effects of FT on soil consistency limits. Improvement of soil consistency limits is not only important for protecting soils against mechanical forces, erodibility and consolidation but also for preparing a good seedbed.