Effects of micro-nano-lime (CaCO3) particles on the strength and resilience of road clay beds

Abstract

Increasing land value and the importance of modern and high-rise buildings have made it inevitable to strengthen weak or low-strength clay beds for construction. Due to its low cost, high availability, and positive strength effects, lime has long been utilized for stabilizing weak soils. However, extensive consumption, a long initial setting time, operating risks, and damaging environmental effects are among the disadvantages of using lime for this purpose. Nanotechnology is the understanding and application of the new properties of nanoscale materials. This interdisciplinary knowledge had considerable positive effects on various engineering trends with the discovery of nanoparticles. In this research, lime powder with specific dry weight percentages of 2, 4, 8, and 16, and lime nanoparticles with specific dry weight percentages of 0.5, 1, 2, and 4 were combined with clay. To analyze soil parameters in terms of engineering, changes in the Atterberg limits, optimal moisture content for soil compaction, maximum dry density, unconfined compressive strength, and the California Bearing Ratio (CBR) were investigated. Based on the results, the optimal weight percentages for lime powder and lime nanoparticles were approximately 4 and 1, respectively. A significant increase in the results of strength tests pointed to the improved performance of lime nanoparticles, compared to lime powder, in terms of both consumption volume and initial setting time. Also, a six-fold increase in CBR reduced the thickness of the pavement layer by 20% by increasing the roadbed resilient modulus (MR).