An Assessment of Geotextiles' Effectiveness as an Earthen Reinforcement in Soil Structures

Abstract

The California Bearing Ratio (CBR) values showed a consistent increase for both clay–fly ash and clay–fly ash–geotextile matrices. Geotextiles contribute to this improvement through their key characteristics: mechanical strength, filtration ability, and chemical resistance. These properties arise from the physical structure of polymer fibers, their processing during textile manufacturing, and the inherent chemical composition of the polymers. Reinforced soil refers to soil strengthened with materials capable of withstanding tensile forces while interacting with the soil through adhesion and/or friction. CBR test results for both matrices reflect the benefits of such reinforcement. In the clay–fly ash matrix, CBR values increased from 11.64% to 14.29% and then to 17.21% as the thickness ratio increased from 1:2 to 1:1 and then to 2:1. Similarly, for the clay–fly ash–geotextile matrix under Standard Proctor compaction energy, CBR values improved from 12.00% to 14.50% and finally to 18.50% for the same thickness ratio progression. However, when the moulding moisture content increased from 16.00% to 34.00% at a 2:1 thickness ratio, the CBR value dropped from 17.21% to 6.77%. Conversely, increasing the compaction energy (Standard Proctor) led to a rise in CBR value from 17.21% to 32.73% for the clay–fly ash matrix at the same thickness ratio. These results highlight the combined effect of thickness ratio, moisture content, and compaction energy on the strength behavior of reinforced soils.