Experimental Investigation and Prediction Model for Mechanical Properties of Barite Concrete

The brittleness of barite coarse aggregates contributes to the deterioration of the mechanical properties of barite concrete (BC). This study quantified the impact of the water-to-binder ratio (w/b) and size effect on the compressive strength of BC. Scanning electron microscope (SEM) analysis was conducted to investigate the underlying deterioration mechanisms, and predictive models for mechanical properties were developed. The results showed that increasing the w/b reduced the size effect on the compressive strength of BC. Specifically, the size effect coefficients γ150 and γ200 of BC at w/b=0.44 and 0.55 decreased by 33.3% and 73.3%, and by 12.5% and 70.8%, respectively, compared with those at w/b=0.39. Additionally, the mechanical properties of BC decreased with increasing w/b. Compared with that with w/b=0.39, BC with w/b=0.55 exhibited decreases of 21.1%, 21.7%, and 17.7% in 4-week splitting tensile strength, flexural strength, and elastic modulus, respectively, whereas 180-day drying shrinkage strain increased by 39.4%. Two of the reasons for the deterioration of mechanical properties of BC were identified as initial cracks in the aggregate and barite chip deposition on the aggregate surface. The predictive models demonstrated strong agreement between calculated and experimental values, confirming their reliability.