Applicability of Scoria Gravel as an Alternative Base Coarse Material through Blending With Marble Waste Aggregate

Abstract

Globally, road construction is one of the most rapidly increasing infrastructure constructions. Natural aggregate is the main component in flexible and rigid pavement construction about more than 95% among required material. The demand of this mineral aggregate increases the magnitude of its extraction. Scoria gravels are pyroclastic materials associated with recent volcanic activity which is mostly found in tropical countries especially MER. In contrast, the marble industry highly affects the environment and natural resources due to more than 30% waste generated. Under these conditions, it is important to look for ways to utilize these wastes to reduce such problems. The main objective of this study is to evaluate the applicability of Scoria gravel through blending with Marble Waste aggregate (MWA) in order to modify their property through mechanical and physical stabilization as a base course material in flexible pavements, in doing so it can reduces extraction of natural aggregate, limit the demands of landfill sites and achieves environmental sustainability. Non-Probabilistic sampling techniques and experimental methods were used. To achieve the objectives of the study, the laboratory tests were passes in three steps. In 1ststep the Engineering properties of materials were independently tested, from the result it was observed that scoria gravel is marginal and low quality material which is susceptible to compaction due to its highly vesicular and lightweight material that was easily broken under applied load, whereas MWA and crushed stone aggregate (CSA) satisfy the minimum requirement of ERA manual for GB2 & GB3 base course material. In 2nd step the laboratory tests for mechanically stabilized Scoria Gravel at (0%, 20%, 40%, 50%, 60%, 80%, and 100%) of MWA by weight was conducted. The obtained test result for 20%Scoria blended with 80%MWA are: SG, ACV, AIV, LAA, FI, EI, PI, WA,OMC,MDD, and CBR of 2.56%, 21.38%, 18.59%, 19.27%, 17.45%, 13.77%, Non Plastic, 1.21%, 4.60, 1.82 and 73.4%, respectively. Thus,20% Scoria Gravel blended at 80% of MWA satisfies all most all the required ERA standard Specification limit of GB2 & GB3 for base course material and selected as control mixture. However, the CBR obtained at this point does not fulfill the requirement which is 73.4% which is less than 80%. Finally, at 3rd step the selected control mix was blended with CSA by another trial and error at (0%, 5%, 10%, 15%, 20%, 25% and 30%) to improve the CBR value, Gradation, Compaction and CBR tests are done and the CBR improved from 73.4% to 82.13% at 25% of CSA blended with 15% Scoria and 60% of marble waste. Therefore, the use of scoria gravel up to 15% blending with 60% MWA and 25% CSA by weight is recommended to use as an alternative base course construction material, when it is found near to the construction site and in places where the materials are abundantly available