Applying at in-Situ Test Fillings of an Improved Clay by Different Additives

This study investigates the improvement of high plasticity clay using pumice, marble dust, and lime additives for use in field test fillings. To determine the optimal mix ratios, consistency limits, standard compaction, unconfined compressive strength (UCS) tests (uncured and cured at 7, 28, and 90 days), triaxial compression, and CBR tests were performed. Based on the results, three mixtures were selected: 67% clay + 30% pumice + 3% lime, 89% clay + 5% marble dust + 6% lime, and 67% clay + 30% marble dust + 3% lime. These were compared with 100% clay as a control. Four 5×5 m test fillings with 0.4 m height were constructed in the field. Plate loading and unit weight tests were performed at placement, on the 7th and 28th days, and again after 7 days of traffic loading applied post-28 days. Surface deformations were monitored and compared to the control fill. The results demonstrated that the use of pumice and marble dust with lime significantly improves the engineering behavior of high plasticity clays. These additives enhanced strength and durability, indicating their suitability for use in clayey soil improvements in field applications.