Carbonation resistance of cementitious systems with iron carbonates
Marjorie Pons Pineyro, Isabella Klimczyk, Marlene Sakoparnig, Florian Steindl, Florian Mittermayr, Joachim Juhart, Augusto Cezar Maciel Soares, Isabel GalanAbstract
In the search for new alternative raw materials for concrete production, siderite (FeCO 3 ) from the Austrian Erzberg mine has been thoroughly tested in recent years as an SCM in both normal concrete and in accelerated systems (i.e., shotcrete). Many hydration mechanisms have been elucidated, and improvements in late strength and various durability parameters have been systematically observed. Previously, it was observed that siderite is capable of consuming portlandite when mixed in OPC, which raised questions about its impact on carbonation resistance. Since carbonation attack is a worldwide widespread durability issue, this investigation studies the carbonation resistance of iron carbonate‐OPC systems. Here, despite lower buffering capacity, a slight improvement in carbonation resistance was obtained thanks to the usage of iron carbonates. This seems to have been caused by significantly more stable Fe‐bearing C‐S‐H in comparison to conventional C‐S‐H, as well as a densified interfacial transition zone.