The impact of different compaction blows in standard proctor test towards electrical resistivity value on clay silt soil

Traditional field density tests for soil compaction are often criticized for being labor-intensive, time-consuming, and limited in coverage. Electrical resistivity offers a non-destructive alternative, providing valuable information about soil parameters such as porosity, moisture content, and degree of saturation. This study investigates the effect of different compaction energies on the electrical resistivity of clay-silt soil using the Standard Proctor test. Soil samples were compacted with a variety of blows (10, 20, 27, 40, and 50) using a standard Proctor mould and 2.5 kg hammer, following BS 1377 guidelines. Electrical resistivity was measured using a Miller 400A Analog Resistance Meter with 1 cm electrode spacing in compliance with BS EN 50522. The results indicated that dry density increased with moisture content, resulting at 23% with a maximum dry density of 1463 kg/m 3 at 40 blows, with values across all energy levels ranging from 1141 to 1463 kg/m 3 . A clear inverse relationship was established between moisture content and electrical resistivity; across the tested moisture spectrum (12% to 43%), resistivity values decreased from a maximum of 134 Ω m (10 blows) to a minimum of 17 Ω m (50 blows). Notably, at the optimum moisture content of 23%, resistivity stabilized within a narrow range of 22 to 27 Ω m regardless of compaction energy. These findings show that electrical resistivity can be used as a reliable and fast method of measuring compaction quality. Furthermore, the resistivity (R) was correlated very well with dry density (ρ d ) and Moisture content (w), with a strong correlation coefficient (R 2 ≈ 85%) and very low p -values, which indicated that these correlations were statistically significant. However, the study was conducted under controlled laboratory conditions with a single soil type and fixed electrode spacing.