Evaluation of Performance of Polyacrylamide-Modified Compacted Clay as a Gas Barrier: Water Retention and Gas Permeability and Diffusion Characteristics

Abstract

In this paper, the performance of a gas barrier that consisted of polyacrylamide (PAM)-modified compacted clayey soil was experimentally explored. The moisture content and water loss characteristics of the tested soils were adopted as indicative indices of water retention capacity (WRC). The gas permeability (Kp) and gas diffusion coefficient (Dp) of the modified compacted clays were evaluated via gas permeability and gas diffusion tests. The test results showed that the moisture content of the modified compacted clay samples subjected to drying tests increased with increasing polyacrylamide content. Kp and Dp decreased with increasing PAM content. Compared with 0.2% PAM content, the Kp of the sample with 1.0% PAM was reduced by ten times, and the Dp was reduced to ~35%. Compared to the unmodified clay, the liquid limit of the PAM-modified clay increased by 45~55%. Comparison of the liquid limit tests between this study and previous studies revealed that the liquid limit ratio of the zwitterionic polyacrylamide (ZP)-modified soil was much higher than the other material-modified soils. The results of this study are useful to facilitate the application of modified compacted clays as gas barrier materials at industrial contaminated sites.

Investigation of Compacted Clay Cover Modified by New Water Retaining Agents

“…6). The operating process of the gas diffusion chamber and the calculation method of gas diffusion coe cient are detailed in Bi et al 2022 [35].…”

“…Therefore, some researchers use non-environmentally hazardous waterretaining agents to enhance the water-holding capacity of soil and suppress soil cracking. These waterretaining agents including zeolites [32], attapulgite [33], biochar [34], polyacrylamide [35], sodium polyacrylate [36], etc. Zeolite has excellent water adsorption [37][38] and retention properties [32,[39][40].…”

Functional Materials Made by Combining Hydrogels (Cross-Linked Polyacrylamides) and Conducting Polymers (Polyanilines)—A Critical Review

“…The hydrophilic gels swell strongly (>20.000%) in water [ 8 ], and the more hydrophobic polymers also swell in nonaqueous solvents [ 9 ]. Similar to other synthetic hydrogels, their large water retention capacity makes them useful in drug release [ 10 ], water absorption [ 11 ] and decontamination [ 12 ], sensors [ 13 ], actuators [ 14 ], etc. The gels are produced by radical polymerization (homo or copolymerization) of the monomer in the presence of a crosslinker (a diacrylamide or hydrophilic diacrylate) [ 15 ].…”

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

“…Fly ash, geosynthetic clay liner (GCL), compacted clay cover (CCC), sludge, and sawdust are commonly used as the source control methods for AMD pollution problems in engineering [ 2 ]. The CCC has the advantages of a wide source, simple construction, and excellent waterproofing and air-blocking performance [ 5 , 6 ], which can effectively inhibit the infiltration of oxygen and rainwater into tailing ponds and prevent the reaction of metal sulfide in the tailings from generating AMD. Due to the influence of water fluctuation and temperature change, the engineering soil (e.g., CCC, roadbed clay, foundation clay, and so on.)…”

“…Water-retaining agents can quickly absorb and preserve water and reduce desiccation cracking [ 5 ]. Soltani et al [ 12 ] show that after adding polyacrylamide (PAM) into the rubber-modified expansive soil, the link between the rubber and soil particles is enhanced due to the role of the polymer binder.…”