ASR products and ettringite were observed in many locations of concrete samples such as at the rim
around aggregates, in voids and in cracks of paste and aggregates, by using microscopic examination.
The amount of ettringite and ASR products was consistent with the damaged levels of the concrete
structures. The evidence of ettringite at 100-cm depth were compared with that at 30-cm depth. The
analytical results of semi-adiabatic temperature rise in mass concrete, which could increase over 70°C,
supported the possible occurrence of DEF. The formation of ettringite was considered to be not involved
with the external sulfate attack. All investigated results confirm that ASR and DEF are two of the main
causes of cracks in the investigated mass concrete structures.