Improving Some Geotechnical Properties of Cohesive Soils by Adding Basalt Fibers and Portland Cement in Basra Governorate - Southern Iraq
A cohesive soils sample was chosen, and soil improvement was completed in three stages. After a series of geotechnical studies, the first stage involved adding 2, 4, 6, and 8% Portland cement to the soil to identify the appropriate proportion for improvement. Experiments have shown that Portland cement with an 8% content is the best. In the second stage, 2, 4, 6, and 8% of basalt fibers with a length of around 1 mm were added to the soil to see how they affected it, and it was discovered that adding the fibers resulted in a significant improvement , , it reached 4269.93 kPa. It was noticed that the values of the internal friction angle increased in the direct shear strength test from 0.4° to 16.5°, and the cohesion increased from 2 kPa to 26.56 kPa. In the consolidation test, it was noticed that the values of the swelling index decreased from 0.027% to 0.005%, the compressive index was 0.38% to 0.05%, and the Pre-Consolidation increased from 65 kPa to 121 kPa, and the absorption percentage decreased from 25.2% to 10.5%.
The process for the third stage is then followed, which entails adding the proportions of 2, 4, 6, and 8%. We proceeded from basalt rock fibers to better soil with the best percentage of Portland cement, which is 8%, to find the best proportion of fibers and to know the progress in specifications. The findings show that adding basalt fibers to Portland cement-treated soils considerably enhanced the categorization and engineering characteristics of the cohesion soils from the study site. After a 28-day treatment period, mixing 8% fibers with 8% cement resulted in a considerable increase in unconfined compressive strength, as well as a large increase in the liquid limit and plasticity limit.