Development of a Low-cost Jute Fibre Reinforced Cementitious Composites Using Locally Available Ingredients

Abstract

The objective of this research is to develop a cost-efficient, optimized Jute Fibre Reinforced Cementitious Composites (JFRCCs) by incorporating locally available constituents and industrial by-products. This study utilized OPC, fly ash, processed sand, jute fibre, and superplasticizer as constituent materials. The experimental program was conducted in three sequential phases. Phase I investigation focused on identifying the influence of mixing components like water-to-binder proportion (W/B), sand-to-binder proportion (S/B), fly ash-to-cement proportion (FA/C), and jute fibre length on compressive strength and determining their suitable range for Phase II investigation. In Phase II investigation, a Full Factorial statistical design of experiments was employed, focusing on four key mixing parameters: W/B, S/B, FA/C, and jute fibre content. From the Phase I investigation, these mixing parameters were set within their specific lower and upper limits as W/B (0.26 and 0.29), FA/C (1.2 and 2.0), S/B (0.3 and 0.5), and jute content (0.5 % and 1.0 %). A total of 16 mixes were designed and for each mixes, compressive strength, peak strain, splitting tensile strength, and ultrasonic pulse velocity (UPV) were investigated at 28 days of casting. The findings indicated that the developed JFRCCs satisfied the minimum standards for residential concrete as per ACI 318. Life cycle assessment (LCA) was also conducted for all mixes which revealed that emitted CO2 from material, transport, and mixture varies from 458 kg/m3 to 668 kg/m3. Following statistical analysis of the experimental data and material costs for 16 mixes, optimized mix proportion for proposed composites was established via a multi-objective desirability approach implemented in Minitab software. The regression and ANOVA analyses revealed high model accuracy and significance for compressive strength, tensile strength, UPV, and XVIII material cost, though not for peak strain. The effect of individual mix proportions on mechanical characteristics and cost-effectiveness of cementitious composites was evaluated before the implementation of the multi-objective desirability approach. With a desirability score of 0.9614, the optimized mix ratio consisted of a W/B of 0.26, FA/C of 1.68, S/B of 0.50, and a jute content of 0.63%, achieving a compressive strength of 35 MPa and a splitting tensile strength of 4 MPa, while simultaneously maximizing peak strain and UPV, and minimizing material cost. Following mix optimization, the Phase III investigation on optimized JFRCCs revealed that both water curing and wet curing methods demonstrated greater compressive behaviour compared with natural curing, indicating critical role of adequate moisture in enhancing hydration and overall performance. Furthermore, during the flexural behaviour assessment, the predominantly brittle failure mode highlighted the necessity for further optimization of the composite mix design and fibre content in order to achieve the desired ductility. Under thermal exposure, JFRCCs exhibited superior resistance compared to conventional concrete, with compressive strength maximizing at 400 °C before declining significantly due to thermal degradation of fibre and matrix dehydration. Microstructural analysis supported these findings by revealing changes in internal structure across different thermal conditions. The study concludes that optimized JFRCCs offer promising potential as a sustainable and cost-effective construction material, exhibiting adequate mechanical and thermal performances.