Durability-related transport properties and microstructural evolution of pavement concrete incorporating recycled sugarcane bagasse

Abstract

The growing demand for sustainable construction materials has stimulated interest in the utilization of agricultural by-products in concrete. Recycled sugarcane bagasse (RSB) represents a potentially valuable bio-based resource; however, its influence on durability-related performance and microstructural development in concrete remains insufficiently understood. This study investigates the effects of incorporating RSB at dosages of 0–2.5% (by volume of concrete) on porosity, water absorption, chloride-ion penetrability, and microstructural characteristics of concrete. A comprehensive experimental program was conducted, including porosity and water absorption measurements, rapid chloride penetration test (RCPT), and microstructural analyses using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TG/DTG). The results show that increasing RSB content progressively increased porosity from 9.24% to 21.74%, water absorption from 3.93% to 10.59%, and the charge passed from 1332 to 4119 C, indicating reduced resistance to chloride ingress. Microstructural observations revealed that increasing RSB content progressively disrupted matrix continuity and increased internal heterogeneity, leading to a more open pore structure and reduced resistance to fluid and ionic transport. In contrast, mixtures containing low RSB contents (0.5–1.0 vol.%) showed less pronounced deterioration in durability-related indicators than mixtures with higher RSB contents. Overall, the findings indicate that while excessive RSB incorporation can adversely affect matrix compactness and transport resistance, limited dosages may be less detrimental and remain technically feasible within the investigated mixture range.