Mechanical behavior of calcareous tuff and coal mine tailings mixture as an embankment material for road construction

Abstract

The construction of embankments requires available and suitable material that sounds to the imposed load. The selection of materials that provide slope stability and maintain pavements is made through specific test control. This research aims to analyze the mechanical behavior of a mixture of 75% calcareous tuff and 25% coal mine tailings (CMTs) used on embankment foundations. the impact of particle size characteristics and the compaction on the mechanical behavior of the mixture are studied. The direct shear test was conducted on different material states, granular and uncompressed states, compaction at the Maximum Practical Optimum (MPO), and MPO compaction post a 30-day curing period at 40 degrees Celsius. the normal stress applied ranging from 50 to 500 KPa, with a constant shear rate displacement of 0.5 mm/min. The results show a substantial influence of compaction on both friction angle (φ) and cohesion (C) values. a remarkable increase in cohesion values after the curing period, attributed to the cementitious compound formation from the interaction between calcareous tuff and coal mine tailings. This investigation emphasizes coal mine tailings potential as a sustainable and cost-effective embankment material for road construction, especially in arid regions. The material exhibits significant shear strength, with a marked increase in cohesion values post-curing state. These results are conducted to consider coal mine tailings as an appealing alternative to traditional materials of road engineering.