By using specimens due to ASR which were simulated according to actual structures, authors carried out a long-term measurement of the external cracks in the specimens at outdoor environment. Moreover, the internal cracks, the compressive strength in core and cracks of reinforcing bars, have been justified at the low, middle and the high reactivity during the deterioration in ASR. It was confirmed that compared with the internal cracks, the apparent cracks were relatively wider and longer. The comparison of strengths between health core and ASR core was conducted as well. With the difference of diameters between 30mm and 190mm, it was confirmed that the compressive strength reduced about 30%.
