To optimize the design of concrete beams and assess the performance of new materials, four-point bending tests were conducted to examine the bending behavior of alkali-activated concrete (ALAC) beams with different reinforcement ratios. The cracking load, displacement, and crack width were measured using the Digital Image Correlation (DIC) method and compared with results obtained through traditional methods. The findings demonstrate that DIC significantly outperforms traditional techniques in determining crack load, displacement, and crack width, particularly in capturing crack initiation and propagation. As the reinforcement ratio increases, the mid-span displacement at the peak load decreases for ALAC beams. At the same reinforcement ratio, the ALAC beam exhibits 1.07 times the bearing capacity, 1.4 times the mid-span displacement, and 0.72 times the maximum crack width compared to ordinary Portland cement concrete (PCC) beams. The cracking load, calculated using a plasticity coefficient of 1.17 for the section resistance moment, aligns closely with the experimental results. Furthermore, the formulas for mid-span displacement and maximum crack width in ordinary concrete beams can also predict the corresponding properties of ALAC beams. These findings validate the mechanical behavior and application potential of ALAC beams under various reinforcement ratios.