Building Materials Capillary Rise Coef ficient: Concepts, Determination and Parameters Involved Nikos Karagiannis, Maria Karoglou, Asterios Bakolas and Antonia Moropoulou Abstract The presence of water is one of the main decay factors in buildings. Capillary rise is the most important mechanism of water penetration into building materials in liquid phase. The free capillary water uptake experiment, used for the estimation of the capillary water absorption coef ficient, a crucial materials property, is widely used for the characterization of building materials. The capillary water absorption coef ficient was calculated according to three different European stan- dards and recommendations. The three methods were compared in order to investigate which is the most appropriate for the calculation of the capillary water absorption coef ficient. In addition, the effect of temperature on the estimation of the capillary water absorption coef ficient of different building materials such as stones, bricks and mortars, was investigated for three different room temperatures (20, 25, 30 °C). From the results it was found a linear dependence between temperature T and the capillary water absorption coef ficient. Keywords Capillary rise coef ficient Á Temperature Á Stones Á Bricks Á Mortars Á Building materials Nomenclature ε o Total porosity (%) g Gravitational constant (m/s 2 ) h Capillary moisture equilibrium height (m) σ Water surface tension (dyn/cm) T Air Temperature (°C) V p Total pore volume (mm 3 ) V b Material bulk volume (mm 3 ) V s Material total volume (mm 3 ) N. Karagiannis Á M. Karoglou Á A. Bakolas (&) Á A. Moropoulou Department of Materials Science and Engineering, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 15780 Athens, Greece e-mail: abakolas@mail.ntua.gr © Springer Science+Business Media Singapore 2016 J.M.P.Q. Delgado (ed.), New Approaches to Building Pathology and Durability, Building Pathology and Rehabilitation 6, DOI 10.1007/978-981-10-0648-7_2 27