Chloride and chemical acid resistance analysis of concrete blends with cassava starch and xanthan gum: innovations in sustainability

Concrete durability is a fundamental criterion influencing the long-term performance of civil engineering infrastructure. Conventional durability enhancement strategies typically rely on synthetic chemical admixtures, which often entail environmental and ecological drawbacks. This study investigates the efficacy of bio-based admixtures—specifically a cross-linked formulation of cassava starch and xanthan gum—as sustainable modifiers to improve concrete durability. The admixtures were incorporated into concrete at three dosages (0.5%, 1%, and 1.5% by weight of cement), and specimens were exposed to 5% concentrations of H2SO4, NaOH, and NaCl solutions under controlled conditions for up to 90 days. Durability performance was assessed through compressive strength retention, mass variation, and permeability, with the latter evaluated using the Rapid Chloride Permeability Test (RCPT) in accordance with ASTM C1202. The 1.5% admixture blend demonstrated the most favorable performance, showing minimal strength degradation, reduced mass loss, and significantly decreased chloride ion penetrability. Microstructural analysis suggested improved pore refinement and enhanced interfacial transition zones, contributing to the material’s resistance against chemical ingress. The results validate the potential of these natural admixtures to function as sustainable substitutes for conventional additives, delivering superior resistance to chemical attack while reducing ecological impact. This research advocates for the integration of bio-derived polymers in concrete technology to advance green infrastructure without compromising structural integrity.