Abstract
Arabic gum biopolymer (AGB) has recently been demonstrated to improve mechanical and physical properties of fresh and hardened concrete which makes it a promising sustainable and environmentally friendly water-reducing admixture. The present work focuses on the effect of added AGB on the workability, setting time, and durability of concrete. Furthermore, a microstructure analysis is conducted to provide objective evidence and support for previous findings and hypothetic interpretations. Flow table experiments are conducted on Portland cement mortar mixed with different percentages of AGB to evaluate the workability. The initial setting time of cement paste is measured for different AGB contents. X-ray fluorescence tests are performed on cement-AGB mix powder to determine its chemical composition. Carbonation depth in AGB concrete samples is estimated to assess durability. AGB-added cement powder was subjected to X-ray diffraction and SEM tests to determine the rate of hydration and to expose the microstructure properties of AGB cement mix and help explain its macroscopic behavior, respectively.