Shear Strength Improvement of Clay Soil Stabilized by Coffee Husk Ash
Reza Pahlevi Munirwan, Mohd Raihan Taha, Aizat Mohd Taib, Munirwansyah Munirwansyah
Abstract
Finding alternatives to natural resources is important for a sustainable future and is essential to infrastructure projects. Among these replacements is the use of coffee waste as soil stabilizers. Coffee husk ash (CHA) is a solid waste obtained by the processing of coffee beans on a farm or factory. The main aim of this study is to determine the geotechnical properties of clay soil treated with CHA to develop a low-cost, environmentally friendly alternative composition. Laboratory tests were conducted to investigate the influence of CHA on the physical properties and the mechanical properties of clay. The CHA concentration was adjusted from 5% to 25% by the dry weight of clay in 5% increments. The clay classification of the mixture becomes coarser following the addition of the CHA. At 25% CHA, a peak UCS of 130.83 kN/m2 was measured compared with the untreated clay of 89.17 kN/m2. In addition, the cohesion values and internal friction angles of soil for 0% and 25% CHA increased from 80.1 kN/m2 to 148.7 kN/m2 and from 16.1° to 25.8°, respectively. It was found that CHA can improve the strength of clay by forming a pozzolanic and hydration process that fills soil voids and binds particles together.