Assessing the reliability of the lightweight deflectometer method for compaction control in highway base layers through SPSS analysis

Lightweight Deflectometer (LWD) is a portable device used to measure the load bearing capacity of subgrades, unbound and granular layers, and backfill materials. Accurate and reliable soil compaction assessments are critical in road construction and maintenance projects. Among the existing techniques, LWD stands out for its portability, convenience, and ease of use. However, its reliability remains a topic of ongoing research compared to established methods like the Nuclear Density Gauge (NDG) and Sand Cone (SC) methods. This study aims to fill this gap by conducting a comprehensive comparative analysis of the LWD, NDG, and SC methods. Data were collected from 15 points where each point was subjected to all three methods along a road construction project in Gümüşhane. The collected data were processed using the Statistical Package for the Social Sciences (SPSS) to evaluate the consistency, accuracy, and reliability of LWD in soil compaction assessment and analyzed using regression, correlation, ANOVA, factor analysis, and T-Test methods. The study investigated inconsistencies or correlations among the results obtained from these different techniques. The findings of this research have significant implications for soil compaction evaluation practices in road construction. Weak correlations observed between LWD stiffness and density-dependent parameters highlight the need for complementary use rather than relying solely on LWD as an independent tool. Combining the stiffness data from LWD with density and moisture measurements from NDG or SC would provide a more comprehensive assessment of compaction quality. In conclusion, this research contributes to the understanding of soil compaction evaluation techniques and provides valuable insights for decision-makers in civil engineering and infrastructure development.