Korea Institute of Construction Materials, Construction Material Research Center, Seoul 137-707, KoreaABSTRACT The majority of research that has been performed on cracking potential of concrete by shrinkage has assumed thatconcrete acts as a homogeneous material. However, with this approach, it is not able to evaluate the micro-cracking behavior inconcrete due to autogenous shrinkage under unrestrained boundary condition (free boundary condition) nor to understand the crack-ing behavior properly because of the heterogeneous nature of concrete. To better understand the micro-cracking behavior of con-crete induced by autogenous shrinkage, series of experiments were performed measuring the length change and acoustic emissionenergy. As an analytical approach, this research uses an object oriented finite element analysis code (OOF code) to simulate thebehavior of the concrete on a meso-scale. The concrete images used in the simulations were directly obtained from mortar samples.From the experiments and simulation results, it was able to better understand the micro-cracking behaviour of concrete due toshrinking of paste phase and internal restraint by aggregates.Keywords : unrestrained condition, micro-cracking, acoustic emission, finite element analysis, internal restraint