Use of Tara Ash and Coconut Fiber in the Mechanical Properties of Concrete

The use of natural additives such as tara ash (TA) and coconut fiber (CF) represents a sustainable alternative to improve the mechanical properties of concrete, due to their local availability, low cost, and potential to reduce the environmental impact of construction. This study evaluates the combined effect of both materials on the mechanical properties of concrete. A two-factor factorial experimental design with 4×4 levels was employed, varying four levels of TA (0%, 6%, 12%, and 16%) and four levels of CF (0.0%, 0.5%, 1.0%, and 1.5%). The mixtures were tested at 28 days to determine compressive, flexural, and indirect tensile strength, applying statistical methods such as ANOVA and the Tukey test. The results showed that using 6% TA without CF increased compressive strength by 1.4%. In flexural strength, the best results (43.5 kg/cm²) were obtained with 0.5% and 1.0% CF without TA. For indirect tensile strength, combinations with low levels of both additives matched the base concrete, while higher proportions (16% TA and 1.5% CF) significantly reduced strength. It is concluded that moderate use of these natural additives can improve the mechanical performance of concrete and contribute to sustainable, low-impact environmental solutions.