There is a dearth for practice-based approaches to model ASR/DEF related expansion in reinforced concrete. A minimalist semi-empirical model is developed to simulate ASR/DEF induced expansion strains in reinforced concrete. The model accounts for the reinforcement ratio, the effects of externally applied compressive and tensile loads, and the variation in temperature and moisture, thus expanding the applicability of the proposed model to concrete structures exposed to field conditions. The modeled longitudinal and transverse expansion strains compare well with the measured expansion strain data from small-scale laboratory specimens, and large-scale spliced column specimens exhibiting ASR/DEF related expansion. © 2016 Elsevier Ltd