Influence of Cocoa Cob Fibre on the Durability and Performance of High-Strength Concrete

Abstract

The increased traffic on road infrastructure has led to higher maintenance costs, particularly for flexible pavements, while rigid pavements, despite their greater durability, require significant initial investment. In Latin America, rigid pavements are preferred for their long-term cost-effectiveness, but they can deteriorate over time. To address these challenges, this study investigates the use of cocoa pod fibers as a natural admixture in concrete to improve its mechanical, thermal, and workability properties, and ultimately enhance the durability of pavements. High-strength concrete (280 kg/cm²) was mixed with cocoa pod fibers at dosages of 0%, 1%, 2%, 3%, and 4%. Key tests, including slump, unit weight, air content, compressive strength, and flexural strength, were conducted. The results revealed significant improvements in workability and mechanical performance, especially at dosages of 1% and 2%. These dosages provided an optimal balance between strength, flexibility, and cost-efficiency, making the concrete suitable for rigid pavement applications. Furthermore, the incorporation of 4% cocoa pod fiber resulted in a 2.32%. Thermal properties were also enhanced, with the addition of 2% cocoa pod fiber lowering the temperature by 0.7°C. Compressive strength increased by 15% with 1% fiber, and flexural strength peaked at 36.5 kg/cm² with 2% fiber. The economic analysis revealed that the incorporation of 1% fiber in the concrete generated a 2.19% increase in the unit cost, which is equivalent to an increase of approximately 11.68 soles per cubic meter compared to concrete without admixtures. This additional cost is justified by improvements in mechanical properties, such as higher compressive and flexural strength, as well as improved workability of the concrete.