Natural fiber reinforcements in cement-based composites: A review on recent advances, properties, and sustainability

Abstract

Amidst increasing environmental awareness, the integration of engineered natural plant fibers such as hemp, jute, flax, coir, and bamboo into cement-based composites has emerged as a significant research focus, offering a sustainable alternative to conventional polymeric fibers. These fibers, known for their eco-friendliness, recyclability, and biodegradability, have shown promising potential in reinforcing concrete, thereby contributing to the development of greener building materials. However, despite the growing body of literature on natural fibre applications, existing reviews often overlook critical aspects such as micromorphological behavior, long-term durability, and fibre–matrix degradation mechanisms under real-world exposure conditions. This review paper synthesizes findings from comprehensive reviews and analyses of recent research covering micromorphology, durability, mechanical and physicochemical properties, and the dynamic interaction between fibers and cement matrices. The study systematically evaluates the enhancements in mechanical strength, particularly in compressive, tensile, and flexural capacities, and discusses the environmental benefits, including reduced carbon emissions and the promotion of agricultural waste utilization as reinforcement sources. While previous reviews have largely emphasized performance metrics in controlled settings, this paper offers a multidimensional perspective that bridges microstructural behavior with environmental sustainability and durability criteria. Despite these advantages, challenges such as the fibers' high moisture absorption, hydrophilic nature, and the resultant weak bonding with the concrete matrix highlight the need for advanced modification methods. Both physical and chemical treatments have been explored to improve fiber durability and compatibility with cement, alongside strategies to mitigate alkaline degradation. The paper also reviews the varied applications of engineered natural fiber-reinforced cement-based composites, notably in road pavements, infrastructure, and residential buildings, while acknowledging the current predominance of laboratory over practical, field-scale implementations. The current review concludes with an insight into the barriers to broader adoption, such as dispersion limitations, inconsistent standards, and fibre variability. It proposes directions for future research, including hybrid fibre strategies, tailored admixture formulations, and improved understanding of fibre–cement chemistry. By providing this comprehensive scope, the review distinguishes itself from earlier studies and positions engineered natural fiber composites as a promising class of materials for advancing sustainable and high-performance construction. • Natural fibers lower CO₂ emissions by replacing synthetic fibers and valorizing agricultural waste. • Optimized natural fiber dosages improve tensile strength, thermal insulation, and acoustic behavior. • Uniform fiber dispersion in cement matrices often requires advanced processes such as Hatschek. • Alkaline degradation of natural fibers can be reduced using surface treatments and matrix design. • Further study is needed on fiber–cement chemistry and admixture effects on durability and bonding.

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