Cover
Vol. 20 No. 1 (2026)

Published: April 29, 2026

Pages: 14-30

Research Article

Multi-Variable Performance Evaluation of Plastic Concrete for Dam Cut-Off Walls

Shanaz Ahmed 1 Dillshad Khidhir 2
1 Salahaddin University - Erbil
2 Department of Civil Engineering, College of Engineering, Salahaddin University-Erbil, Erbil, Iraq
History
  • Received: August 16, 2025
  • Revised: December 27, 2025
  • Accepted: January 6, 2026
  • Available Online: June 30, 2026
DOI

https://doi.org/10.37650/ijce200102

Abstract

Plastic concrete is widely used in hydraulic cut-off walls of earth and rockfill dams because of its low permeability, high deformability, and good workability. The addition of bentonite clay is also among the primary factors that can influence its performance as it greatly decreases the hydraulic conductivity. Mechanical performance and crack resistance are enhanced by the fiber reinforcement of polypropylene (PP) and steel fibers. This paper investigated the interaction of calcium bentonite dosage, fiber type and content, cement content, and water-to-binder ratio (W/(C +B)) on the flowability, compressive strength, and permeability of 29 plastic concrete mixtures to be used in cut-off wall construction. The experimental tests were performed in accordance with ASTM D6103 on flowability, ASTM C39 on compressive strength and BS EN 12390-8:2019 on permeability. The findings revealed that the best mixtures had a flowability of over 14 cm, compressive strength of 1.23 to 25.78 MPa and permeability coefficients of 10⁻⁹ to 10⁻⁷ cm/s. Adding more bentonite was a very effective way of decreasing permeability, but frequently had adverse effects on compressive strength and workability. Polypropylene fibers showed a more favorable contribution to crack resistance and workability compared to steel fiber. The findings indicate that close fine-tuning of the water to binder ratio (W/(C+B)) as well as dosages of superplasticizer is essential in attaining balanced performance. The study presents a guideline to enhance durable, non-pervious, plastic concrete that can be used in hydraulic works and prepares the groundwork in future investigations of long-term durability and chemical integrity.

Keywords

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