Feasibility of using CDW fine fraction and bentonite mixtures as alternative landfill barrier material
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ORIGINAL ARTICLE
Feasibility of using CDW fine fraction and bentonite mixtures as alternative landfill barrier material Natalia de Souza Correia1 · Renan Cesar Silva Caldas1 · Johnson Rotimi Oluremi2 Received: 12 November 2019 / Accepted: 24 June 2020 © Springer Japan KK, part of Springer Nature 2020
Abstract Construction and demolition waste (CDW) appear with potential application reused in sanitary landfills as alternative barriers, especially considering the use of its fine fraction. To fulfill literature requirements for landfill liners, the combination of CDW with bentonites appears as a feasible solution, while minimizes the use of natural resources and final CDW disposal problem. This paper describes the geotechnical performance of mixtures of CDW fine fraction with different contents of high-swelling sodium bentonite as well as chemical influence of curing time. Results showed that the plasticity of the mixtures was significantly increased with few bentonite contents. Compaction results were presented and unconfined compression strength results achieved minimum 200 kPa. Hydraulic conductivity drastically decreased with bentonite addition, reaching values of 10–9 m/s 16% bentonite content. A high increase in the CEC was observed in the CDW–bentonite mixtures, corroborating to material application in landfills. The presence of CDW fine fraction reduced the free swell index of bentonite. The curing period of 180 days showed to reduce swelling results, mainly due to the presence of calcium, magnesium oxide and pozzolana reactions. This research showed the feasibility of using CDW–bentonite mixtures as a landfill liner material. Keywords Geotechnical properties · Landfills · Construction and demolition waste · Bentonite · Hydraulic conductivity · Swelling
Introduction Diverse combination of materials has been suggested, investigated and used in the design and construction of landfill liners. The use of bentonite composite materials in the construction of landfill liners has increased rapidly, although the use of clay liner as a barrier is frequently used in many countries [1]. Clayey soils (mostly bentonites) have been traditionally used to construct base landfill liners due to their low cost, large leachate attenuation capacity, resistance to damage, very small particle size, high surface area, cation * Natalia de Souza Correia [email protected] Renan Cesar Silva Caldas [email protected] Johnson Rotimi Oluremi [email protected] 1
Federal University of Sao Carlos, Washington Luis Road, km 235, Sao Carlos, SP, Brazil
Civil Engineering Department, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
2
exchange capacity (CEC), high-swelling behavior, and especially very low hydraulic conductivity to water [2, 3]. Generally, minimum requirements for CCL refer to clay particle size distribution, mineralogy, strength parameters, plasticity index, CEC and hydraulic conductivity [4–7]. Unfortunately, no unified and comprehensive international legal regulation of applicability of mine
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