Acoustic emissions (AE) released during the compressive fracture of cementitious materials 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 specimen and by using the AE based b-value analysis, it is possible to study fracture process and 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 details related to original G-R relation and it’s suitability for AE testing were discussed. In this article it has been tried to look into the variations of the AE based b-value in cementitious test specimens prepared with different cementitious mixture propor- tions. Effect of (i) coarse aggregate size in cementitious materials (ii) loading rate during compressive fracture process (iii) age of concrete on b-value variation were discussed. 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. When the 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.
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