Effects of natural zeolite and sulfate environment on mechanical properties and permeability of cement–bentonite cutoff wall. Issue 3 (17th February 2023)

• Record Type: Journal Article
• Authors: Akbarpour, Ali; Mahdikhani, Mahdi
• Is Part Of: European journal of environmental and civil engineering. Volume 27:Issue 3(2023)
• Page Start: 1165
• Page End: 1178
• Publication Date: 2023-02-17
• Subjects: Natural zeolite -- sulfate attack -- slurry cutoff walls -- permeability -- pH values -- unconfined compressive strength; Sustainable engineering -- Periodicals; Civil engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; 628
• DOI: 10.1080/19648189.2022.2075940
• Languages: English
• ISSNs: 1964-8189

Abstract

Abstract: Cement–bentonite (CB) slurry cutoff walls are extensively utilized to restrict the horizontal flow of fluids. In this study, cement was replaced by four various contents of 0%, 10%, 20%, and 30% by natural zeolite to evaluate its effects on the unconfined compressive strength, flexural strength, tensile strength, and the coefficient of permeability of cement–bentonite– zeolite (CBZ) specimens. Since underground cutoff walls are always in danger of sulfate attack, the CBZ specimens were immersed in three different containers with three different pH values of 2, 5, and 8 to study the sulfate resistance of this material. Results have indicated that the strength of specimens decreases with an increase in zeolite content at early ages; however, increasing the amount of zeolite up to 20% improves the mechanical properties and permeability of cutoff wall materials at late ages. The bentonite/cement (B/C) ratio equal to 0.2 shows a relatively better response than B/C ratios equal to 0.14 and 0.3. Curing specimens in the sulfate environment increased the mechanical strength of specimens and decreased the coefficient of permeability at first ages. At the late ages, curing in sulfate solutions manifested disadvantageous effects on specimens; however, specimens containing zeolite indicated higher sulfate resistance than specimens without zeolite.