Mineral Identification as an A-7-5 Clay Stability Indicator Using Volcanic Ash

¹ Department of Civil Engineering, Syiah Kuala University, 23111 Banda Aceh, Indonesia
² Department of Civil Engineering, Syiah Kuala University, 23111 Banda Aceh, Indonesia

^* Corresponding author: annenoviasiregar@gmail.com

Abstract

Soil is a building material and the foundation of the structure, it must be considered. There are bumpy roads and collapses on Jalan Elak Lhokseumawe. This study’s primary focus is on road subgrade. Because of its high plasticity index and clay minerals that swell when water is added, the soil cannot be used as a subgrade. Volcanic ash from Burni Telong Bener Meriah was used in this study. The combined volcanic ash content ranges between 7.5% and 15%. The goal is to see if the bearing can be stabilized afterward. Based on XRD analysis, this soil has an illite clay mineral content with a WT value of 0.817%. The Atterberg limit test on soil is classified as A-7-5 by AASHTO and MH by USCS. At a percentage of 12.5% volcanic ash, the CBR test results for soaked and unsoaked conditions yielded optimal values of 5.9% and 9.4%, respectively. The swelling value continued to fall at a percentage of 12.5% volcanic ash. UCS test results in soaked and unsoaked conditions at 12.5% volcanic ash percentage yielded optimum values of 1.46 kg/cm2 and 2.18 kg/cm2, respectively. The soil is found to be usable, but it needs to be stabilized.