Hydraulic and Swell–Shrink Characteristics of Clay and Recycled Zeolite Mixtures for Liner Construction in Sustainable Waste Landfill

Abstract

This paper presents research considering hydraulic as well as swelling and shrinkage characteristics of potential recycled fine particle materials for compacted clay liner for sustainable landfills. Five locally available clay soils mixed with 10% (by mass) of NaP1 recycled zeolite were tested. The performed analysis was based on determined plasticity, cation exchange capacity, coefficient of saturated hydraulic conductivity after compaction, several shrinkage and swelling characteristics as well as, finally, saturated hydraulic conductivity after three cycles of drying and rewetting of tested specimens and the reference samples. The obtained results showed that addition of zeolite to clay soils allowed reduction in their saturated hydraulic conductivity to meet the required threshold (≤1 × 10−9 m/s) of sealing capabilities for compacted clay liner. On the other hand, an increase in plasticity, swelling, and in several cases in shrinkage, of the clay–zeolite mixture was observed. Finally, none of the tested mixtures was able to sustain its sealing capabilities after three cycles of drying and rewetting. Thus, the studied clayey soils mixed with sustainable recycled zeolite were assessed as promising materials for compacted liner construction. However, the liner should be operated carefully to avoid extensive dissication and cracking.

Macroscopic Mechanical Properties and Microstructure Characteristics of Solid Waste Base Capillary Retarded Field Covering Material

“…The study conducted by Rubinos et al investigated the geotechnical and hydraulic characteristics, advantages, and disadvantages of various waste materials, including paper mill sludge, cement kiln dust, biochar modified clay, and red mud as constituents for landfill barriers. The findings of this study demonstrated that the modified sludge fulfilled the requirements for landfill cover materials in terms of unconfined compressive strength and permeability coefficient tests [20][21][22]. The compaction, screening, and CT scan tests were conducted by Li et al on a renewable construction waste mixture.…”

Water-Holding Properties of Clinoptilolite/Sodium Polyacrylate-Modified Compacted Clay Cover of Tailing Pond

“…According to the Unified Soil Classification System [ 23 ], clinoptilolite was classified as silt with a high liquid limit (MH). In order to explore the influence of clinoptilolite content on soil’s water-holding capacity, and in consideration of the hydraulic conductivity, adsorption performance, gas resistance, and other requirements of CCC, the replacement content of clinoptilolite was set as 0%, 3%, 5%, 10%, and 15% according to the literature [ 24 , 25 , 26 ].…”

Investigation of Compacted Clay Cover Modified by New Water Retaining Agents

“…However, some research shows that zeolite did not reduce the desiccation cracking properties of bentonite [43]. And the expansion and shrinkage of zeolite-modi ed clays increase [44]. After three cycles of drying and wetting, the permeability required can not be maintained due to the enhanced cracking properties [44].…”

“…And the expansion and shrinkage of zeolite-modi ed clays increase [44]. After three cycles of drying and wetting, the permeability required can not be maintained due to the enhanced cracking properties [44]. Sodium polyacrylate(Na-PAA) has better water absorption and retention properties than zeolite [36].…”