Soil Stabilization Using Bottom Ash and Areca Fiber: Experimental Investigations and Reliability Analysis

The rapid development of urban areas and the increase in construction activities have resulted in a scarcity of land with favorable soil conditions, necessitating the use of locally available weak soils for construction activities through stabilization techniques. This study introduces a new material, areca fiber, and its suitability as soil reinforcement. Although areca is available abundantly in many parts of the world, its application in geotechnical engineering has not been explored. In the present study, bottom ash (BA) is used as a stabilizing agent, and the suitability of natural areca fiber as reinforcement is demonstrated through detailed experimental investigations and reliability analysis. The test method includes compaction tests, unconfined compression strength (UCS) tests, California bearing ratio (CBR) tests, and split tensile strength tests. The BA content was varied from 0 to 40%, the fiber content was varied from 0 to 1.5%, and the corresponding performance assessment was done. A small amount of cement (3%) was also added to improve the pozzolanic reaction. The UCS and split tensile strength tests were conducted on samples at different curing periods with a maximum curing for 90 days, whereas CBR tests were conducted after 7 days of curing for both soaked and unsoaked conditions. There was considerable increase in UCS, CBR, and split tensile strength of the soil with addition of BA, and the strength values increased tremendously in the presence of areca fiber. Mineralogical and microstructural studies were conducted on the stabilized soil sample using X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. These results confirmed the formation of cementitious compounds in the XRD patterns and showed development of dense matrix in the SEM images. The performance of the modified subgrade soil was validated using a reliability approach, which found that the soil subgrade with BA and areca fiber can certainly be used as pavement material for low-volume applications. (C) 2018 American Society of Civil Engineers.