Geotechnical characterization of alluvial soil blended with quarry waste lime aggregate as an alternative roadway construction material

• Main Author: Torres, Emerzon S.
• Format: text
• Language: English
• Published: Animo Repository 2020
• Subjects: Fluvisols—Testing; Pavements—Subgrades; Waste products as road materials; Quarries and quarrying—By-products—Testing; Limestone—Testing; Geotechnical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/6361; https://animorepository.dlsu.edu.ph/context/etd_masteral/article/13401/viewcontent/Torres_Emerzon_11791896_1Edited_Redacted.pdf
• Institution: De La Salle University

The infrastructure growth in the Philippines promises a significant road construction development and therefore increasing the demand for construction materials. However, the conventional materials in roadway construction are getting depleted. To address the problem of scarcity on construction materials, there is a need to explore alternatives. The main objective of this study was to characterize and assess the potential of the naturally occurring alluvial soils and the locally available waste quarry limestone, individually and proportionally, when used as a road subgrade, subbase/base course, and embankment materials. Theses were done through experimental investigation of the individual and blended samples of alluvial soil and limestone based on the ASTM and AASHTO standards. From the preliminary investigation, the alluvial soil was classified as poorly graded sand with no plasticity. The SEM-EDX and sedimentology of the river sand shows an immature sediments with majority of quartz and chlorite minerals which are very common to sands. On the other hand, the mass percent wear of 34% for limestone makes it a promising aggregate material with a significant resistance to abrasion. These were validated by the SEM-EDX and petrographic analysis of the limestone showing a good preservation and matrix of the minerals. In terms of strength, the CBR value of alluvial soil reaching 41% makes it a suitable subbase material according to the DPWH standards. The controlled sample or the one with pure limestone content is the optimum blend with a maximum CBR value of 397%. The direct shear test for alluvial soil reveal a friction angle of 37.52° and 36.61° for dry and saturated conditions, respectively. A constitutive model was also developed in this study based on the modified hyperbolic and Weibull functions to predict the stress-strain and volume change behaviour of the alluvial soil. The constitutive model effectively captured the stress-strain and volumetric strain-shear strain curves of the test data and satisfactorily define the soil behavior of both dilating and non-dilating soil types.