Acoustic emissions (AE) released during the compressive fracture of cementitiousmaterials have been subjected to analysis using ‘AE based b-value’ to study the frac-ture process. Identification of the ‘AE sources locations’ in three dimension is not al-ways possible. With a minimum number of AE sensors mounted on the test specimenand by using the AE based b-value analysis, it is possible to study fracture processand the damage status in solids. The b-value of AE is calculated using the Gutenberg–Richter empirical relationship (G-R law), which is available in seismology. The detailsrelated to original G-R relation and it’s suitability for AE testing were discussed. Inthis article it has been tried to look into the variations of the AE based b-value incementitious test specimens prepared with different cementitious mixture propor-tions. Effect of (i) coarse aggregate size in cementitious materials (ii) loading rateduring compressive fracture process (iii) age of concrete on b-value variation werediscussed. The trend of variation in AE based b-value during fracture process in con-crete and mortar was different. It was observed that when the compression tough-ness of the cementitious material increases, higher b-values were observed. Whenthe loading rate was high, quick cracking occurred and lower b-values were ob-served. As the coarse aggregate size in the cementitious material increases, the cu-mulative AE energy was higher. The reason may be due to the compression tough-ness of the cementitious material. The AE based b-value is useful to identify the dif-ferent stages of compressive fracture process in solids.