Análisis de las propiedades físicas y mecánicas del uso de ceniza de coco natural para la estabilización de suelos blandos

Abstract

The present study evaluates the physical and mechanical behavior of soft soils stabilized with natural coconut shell ash (CSA), with the purpose of determining its efficiency as an alternative and sustainable material to improve bearing capacity and stability in soils with deficient geotechnical characteristics. This research responds to the need to reduce the use of traditional stabilizers such as lime and cement, whose cost and environmental impacts are considerable, by instead utilizing agro-industrial residues. The work was carried out in three phases. In the first phase, two representative soil samples were collected: one from Puyo (Pastaza) and the other from Baños de Agua Santa (Tungurahua), areas where soft volcanic soils predominate. The ash was obtained through controlled calcination of coconut shells at temperatures between 400°C and 800°C and then sieved to ensure a fine and homogeneous material. Subsequently, the natural soils and the mixtures stabilized with 4%, 6%, and 8% CSA were subjected to moisture content, grain size distribution, Atterberg limits, Modified Proctor compaction, and CBR tests, following ASTM and AASHTO standards. These tests allowed the identification of changes in optimum moisture and bearing capacity. The natural soil exhibited very low CBR values, typical of a deficient subgrade (between 3% and 5% in some cases). With the incorporation of 4%, 6% and 8% CSA, the CBR values showed relevant increases, reaching improvements ranging from 40% to over 100% compared to the natural soil. The results confirm that coconut shell ash can significantly improve compaction and bearing capacity in soft soils. Its performance, combined with its low cost and availability, makes it a technically feasible and environmentally favorable option for road construction projects.