@article{ThielKratzerGrimmetal., author = {Thiel, Charlotte and Kratzer, Johanna and Grimm, Benedikt and Kr{\"a}nkel, Thomas and Gehlen, Christoph}, title = {Effect of Internal Moisture and Outer Relative Humidity on Concrete Carbonation}, series = {CivilEng}, volume = {4}, journal = {CivilEng}, number = {3}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/civileng3040058}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-56091}, pages = {1039 -- 1052}, abstract = {With steadily rising CO2 concentrations in the ambient air and fast-changing concretecompositions with reduced clinker contents, the availability of reliable and accelerated concrete car-bonation tests is of crucial importance to design durable structures. This paper focuses on the effectsof moisture under accelerated conditions and the effects of different CO2 exposure conditions. Mor-tar prisms incorporating three different cement types were cured and stored at either 50\% or 65\%relative humidity (RH). Afterwards, the prisms were carbonated at different ambient humidities(50, 57 and 65\%), different CO2 concentrations (0.04, 1 and 3 vol.\%) and complemented by a seriesof tests at increased gas pressure (2 barg). High-resolution test methods were used to explain theunderlying carbonation mechanisms. The results show that pre-conditioning for two weeks—ascurrently suggested by the European Standard—seems to be too short because the initial inner mois-ture content severely affects the carbonation rate. Relative humidity during carbonation of 57\% ledto higher carbonation rates compared to 50\% and 65\%. In addition, climate data needs to be period-ically (preferably permanently) recorded in research experiments and in laboratory testing to ensurefair interpretation of experimental results.}, language = {en} }