A Comparative Evaluation of Plain, Polypropylene Fiber, and Jute Fiber Reinforced Shotcrete

Abstract

This study intends to establish the mechanical properties of plain , jute & polypropylene fiber reinforced shotcrete (PFRS) in terms of compressive, energy and flexural strengths, in accordance with IS-516/EN-14488/ ASTMC1609/C1609M-12. The mechanical properties identified the influence of polypropylene fiber content on the PFRS strength. In addition, the fiber rebounding rate and PFRS performance in tunneling application were evaluated based on a tunnel application in Indian Railway. Therefore, PFRS applied to a tunnel exhibited stability and constructability.

Introduction

The construction industry is increasingly focusing on sustainable, eco-friendly, and cost-effective materials that improve engineering performance without delaying construction. Shotcrete is a widely used technique for stabilizing slopes and underground excavations by spraying concrete at high velocity onto a surface, providing rapid and effective ground support.

Shotcrete is mainly applied using two methods: dry-mix shotcrete, in which water is added at the nozzle, and wet-mix shotcrete, in which all ingredients are mixed with water before spraying. This study focuses on the wet-mix method because it provides better quality control, uniform mixing, and smoother spraying operations.

The main objective of the study is to investigate the use of natural jute fiber in shotcrete and compare its quality and mechanical properties with polypropylene-fiber shotcrete and conventional shotcrete without fibers. Jute fiber is proposed as a sustainable alternative to petroleum-based synthetic fibers because it is lightweight, economical, renewable, and environmentally friendly. Its addition may improve tensile strength, flexural strength, energy absorption, and bonding ability while reducing rebound losses, equipment wear, and fuel consumption associated with synthetic fiber production.

The literature review indicates that fiber reinforcement can improve crack resistance, ductility, and the flexural performance of concrete. Previous studies on natural fibers have shown that their effectiveness depends on fiber length, percentage, orientation, and distribution within the concrete mix.

Key findings from the reviewed studies include:

• Workability: Increasing jute fiber content generally reduces concrete workability because jute absorbs water and may form fiber clusters.

• Compressive strength: Jute fiber can improve compressive strength up to an optimum content, reported around 0.4% in one study. Excessive fiber content may reduce strength because of poor compaction and fiber agglomeration.

• Tensile strength: Jute fiber can improve splitting tensile strength by bridging cracks and restricting their propagation.

• Flexural strength: Research indicates that jute fiber can increase the modulus of rupture, with improvements depending on fiber orientation and content.

• Fiber optimization: Previous research suggests that fiber lengths of approximately 10–20 mm and contents of around 0.3–0.45% may provide favorable results, although the optimum values vary with the mix design and experimental conditions.

• Durability: Natural-fiber concrete may have reduced resistance to chloride penetration, but the addition of suitable pozzolanic materials may help improve this property.

References

[1] Indian Standard Code, IS: 383-1970 Specification for Coarse and fine aggregate from natural sources for concrete (Second Revision) (Reaffirmed 2002) [2] Indian Standard Code, IS: 456 -2009 Code of practice for plain and reinforced concrete [3] Indian Standard Code, IS: 516-(Part 4): 2018 Hardened concrete-Methods of test. [4] 4. Indian Standard Code, IS: 10262-2009 recommended guidelines for concrete mix design [5] Indian Standard Code, IS: 2386(Part-III)-1963 Methods of test for Aggregates for concrete [6] Kyong Ku Yun , Mohammad Shakhawat Hossain , Seungyeon Han , Choi Seunghak [7] “Rheological, mechanical properties, and statistical significance analysis of shotcrete with various natural fibers and mixing ratios” [8] Mohammad Mohsin1, Tamim Ahmed2, Rehnuma Raheem3, Emad Ahmed4 “Jute Fiber Optimization for Enhancing Concrete Properties: A Review” (7th International Conference on Advances in Civil Engineering (ICACE) [9] Tarikul Islam, Faruk Patowary, Debasish Sen*, Sharmin Reza Chowdhury “Effect of Jute Fiber Content on Compressive and Split Tensile Strength of Concrete Utilizing Stone Chips as Coarse Aggregates” [10] Pramodini Sahu , Chhabirani Tudu, “Effect of Jute Fibre Orientation and Percentage on Strength of Jute Fibre Reinforced Concrete” [11] EN -14488 Part 2 “Compressive strength of young sprayed concrete” [12] 11. EN -14488 Part 5 “Testing sprayed concrete Determination of energy absorption capacity of fibre reinforced slab specimens” [13] 12. EN -14488 Part 7 “Fibre content of fibre reinforced concrete” [14] 13. EFNARC “European Specification for Sprayed Concrete”

Copyright

Copyright © 2026 Priyanka Panjabi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.