At present, the reduction of CO₂ emissions due to the cement manufacture is an important field of study. In this line, the production of commercial cements consisting of binary binders is relatively common. However, the manufacture of commercial cements made with ternary binders is still very low, at least in Spain. In these binders, clinker is partially replaced by two additions, and the synergetic effect of both additions can also improve the behavior of cement-based materials.

In this work, it has been studied the short-term effects of the exposure to a real in-situ environment in the microstructure and properties of mortars prepared with different binders. The in-situ condition consisted of exposing the samples to a Mediterranean climate environment in an inland location sited in Alicante province (Spain), but not too far away from the coast (10 km approximately). This location would accomplish the specifications of exposure class XC4 (corrosion induced by carbonation, cyclic wet and dry) defined by the Eurocode 2.

Reference mortars were prepared with ordinary Portland cement without additions. A binary binder was also studied, incorporating 30% limestone, as well as two ternary binders, with addition 15% limestone and 15% fly ash, and 15% limestone and 15% ground granulated blast furnace slag, respectively. The microstructure has been analyzed using mercury intrusion porosimetry, electrical resistivity and scanning electron microscopy. Absorption after immersion and mechanical strengths have also been studied. According to the results obtained, mortars with ternary binders showed a good behavior in the short-term compared to reference mortars.