The effect of pine tree sawdust on the freeze-thaw resistance of expansive soils

 Necmi Yarbaşı1, Ekrem Kalkan2*
1,2Ataturk University, Oltu Earth Sciences Faculty, Geological Engineering Department, Erzurum, Turkey
*Corresponding author

Abstract—The expansive soils in areas with seasonal frost are exposed to at least one freeze-thaw cycle every year. As a result of this affect, these soils lose their durability’s. To prevent the strength, loss of expansive soils, it is necessary to improve the freeze-thaw resistance of them. In this study, it was investigated the effects of pine tree sawdust on the freeze-thaw resistance of expansive soils as alternative additive material. For this purpose, the natural and stabilized expansive soil samples were exposed to the freeze-thaw cycles under laboratory conditions. Then, the samples unexposed and exposed to the freeze-thaw cycles were subjected to the unconfined compressive tests. The experimental results showed that the pine tree sawdust-stabilized samples with have higher freeze-thaw resistance as compared to unstabilized expansive soil samples. Consequently, it was concluded that pine tree sawdust can be successfully used as an additive material to improve the freeze-thaw resistence of expansive soils.

Keywords— Expansive soil, waste material, pine tree sawdust, soil stabilization, freeze-thaw resistance

I. INTRODUCTION

The clayey soils are generally classified as expansive soils and these soils are known to cause severe damage to structures resting on them. However, these soils are very important in geology, construction, and for environmental applications, due to their wide usage as impermeable and containment barriers in landfill areas and other environmentally related applications (Erguler and Ulusay, 2003; Harvey and Murray, 1997; Kayabali, 1997; Keith and Murray 1994; Murray, 2000; Sabtan, 2005; Kalkan and Akbulut, 2004; Kalkan et al., 2019; Indiramma et al., 2020; Yarbaşı and Kalkan, 2020).
In the cold regions, soils in areas with seasonal frost are exposed to at least one freeze-thaw cycle every year. In the freezing period, subsoil moisture moves towards the frozen layer because of a temperature gradient. Void spaces of soil gradually increase due to frost heave and moisture move to the interstices of the soil and then freezes. In the thawing period, thawing of the frozen layer begins from the top and the bottom at the same time. The maximum soil moisture content appears above the frozen layer and becomes temporarily-perched water. Additionally, the soil moisture content under the frozen layer is more than it was during the prefrozen period (Zhang and Shijie, 2001; Yarbaşı et al., 2007).

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