Isothermal water vapour permeability of concrete with different supplementary cementitious materials

Water vapour permeability (WVP) is a key parameter for the sustainable thermal conditioning of buildings. The study of the WVP in concrete with supplementary cementitious materials (SCMs) allows for the design of structures with improved durability and sustainability. To our knowledge, there is insufficient experimental data in the literature regarding the WVP of concrete with SCMs. WVP tests were made on concrete mixes containing ground granulated blast-furnace slag (GGBFS) and limestone powder (LP) as a partial replacement for ordinary Portland cement, and of concrete mixes containing pozzolanic cement (NP). Results from three moisture gradients show that GGBFS induces the greatest reduction in WVP, followed by the NP. LP shows a diluting effect of the binder, which could be compensated by GGBFS in the ternary blend. From the comparison between the WVP and the capillary sorption rate, the influence of the SCMs on the connectivity of the smallest pores is assessed.