The purpose of this research is to measure the flexural strength of both traditional and newly modified concrete beams with kaolinite coal added. Two sets of eighteen samples each were ready for the data collection. Two sets of specimensare prepared: 18 specimens of one set using modified concrete that has been treated with kaolinite coal, and the other set of 18 specimens using traditional concrete beams. The preparation and examination of the samples involved the use of flexural strength test equipment. The beam specimen size was taken as 100 x 100 x 500mm. The SPSS software version 29 has been utilized to conduct the independent sample T-test. The statistical analysis included Levene’s test for equality of variances and a t-test for equality of means to assess the flexural strength of two groups. Levene's test revealed a significant difference in variances between the groups (F=2.909, p=0.097). Subsequently, the t-test assuming equal variances indicated a highly significant difference in means (t=-16.954, df=34, p=0.000). The mean difference in flexural strength was -1.43578, with a standard error of 0.08469 and a 95% confidence interval ranging from -1.60788 to -1.26367. The t-test assuming unequal variances corroborated the significant difference in means (t=-16.954, df=29.822, p=0.000), with a consistent mean difference and confidence interval. The modified concrete beam sample with kaolinite coal added has a mean flexural strength of 4.75 N/mm2, while the standard concrete beam sample has a mean flexural strength of 2.73 N/mm2.