The observed existence of ASR gel confirmed that ASR is one of the causes of this concrete
deterioration. In the case of DEF, the formation of ettringite could be attributed to either each or a
combination of DEF and external sulfate attack. The formation of ettringite in cored concrete samples
taken from concrete structures at 100 cm depth supported the occurrence of DEF. Since the amount of
ettringite found at 30 cm depth was not higher than those found at 100 cm depth (see Table 1), the internal
DEF has a higher potential than the external sulfate attack, and is one of the distress mechanisms. However,
confirmation by analyzing the semi-adiabatic temperature rise of concrete and determining sulfate content
in soils is to be done in the following sections.