The strength development of cement paste/mortar are of critical importance in structural health monitoring (SHM), as they directly influence early-age behaviour, long-term performance, and damage evolution in cement-based structures. This study explores the suitability of the electro-mechanical impedance (EMI) procedure in monitoring mortar strength development using agro-waste products such as rice husk ash (RHA), and sugarcane bagasse ash (SCBA) with embedded piezoelectric sensors (EPS). In order to measure the changes quantitatively, there are several statistical damage indices that are considered during the process of curing on the basis of EMI signatures. Moreover, the findings of the EMI-based sensing method are compared with others of other non-destructive and destructive testing techniques, such as rebound hammer and compressive strength (CS). The results show that the piezoelectric sensors installed in it can successfully record the strength behavior improvement during the curing process. Besides, the statistical indices as calculated based on the EMI signatures are correlated with the outcome of the destructive tests, to verify the accuracy and the efficiency of the EMI method regarding SHM in agro-waste-based cementitious materials.