Saad Issa Sarsam, Ayah Tawfeaq Kais
Abstract: The main purpose of this research is to assess the impact of asphalt stabilization on the variation in the shear resistance of subgrade soil under static loading. The impact of two testing techniques (double punch) on cylindrical specimen of 100mm diameter and 63mm thickness and (single punch) on cylindrical specimen of 152mm diameter and 127mm thickness has been verified on shear strength using incremental static loading. The testing program for this paper is concerned with the determination of shear stress property of natural and asphalt stabilized subgrade soil under the static loading. The study found that increasing asphalt content above the optimum has a positive impact on single punch test. The percentage of variance relative to natural (untreated soil) is equal to (107, 164, and 261) and (94, 163, and 312) at (2.5 and 5) mm penetration respectively for fluid content equal to (15.5, 16, and 16.5) % correspondingly. Shear strength increases as fluid content increases for single punch test, while it decreases as fluid content increases for the double punch test. At 15.5 % fluid content, single punch test shows higher shear strength by 128 % than that of double punch test. Such variation increases by (278 and 853) % with the increments of fluid content.
Keywords: Granular soil, Liquid asphalt, shear strength, Double punch, CBR