DOI: 10.46810/tdfd.1729919 ISSN: 2149-6366

Use of Ahlat stone powder for expansive subgrade stabilization

Muhammed Tanyıldızı
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Expansive subgrades pose significant challenges to road pavements due to their inherent high volume change potentials and poor load-bearing capacities. This paper focused on the stabilization of the expansive subgrade with Ahlat stone powder (ASP). For this purpose, the soil was replaced with ASP in ratios of 3%, 6%, 9% and 12% by dry weight and a series of physical and mechanical laboratory tests consisting Atterberg limits, swelling/shrinkage, compaction, unconfined compressive strength (UCS) and California bearing ratio (CBR) were performed on specimens with/out ASP. Additionally, scanning electron microscope (SEM) analysis was conducted to monitor the microstructural changes through stabilization. The test results indicated that liquid limit (LL), plasticity index (PI) and swell/shrink potential of soil was reduced consistently with increasing ASP content. The maximum dry density (MDD) of the soil increased, while optimum moisture content (OMC) was reduced steadily with ASP. The UCS and CBR values of soil with a 9% ASP content increased by 55% and 39%, respectively. Considering the CBR values, a reduction of approximately 24% in the required subbase thickness can be achieved with a 9% ASP ratio. The SEM analyses revealed a more compact with less porous microstructure of soil after stabilization.

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