Determination of saturated water conductivity coefficient in building materials

Abstract

Capillary water uptake is a serious phenomenon influencing the functioning of old and newly raised buildings, thus modeling of this process is very important for prediction of the behavior of building objects. Among many models of water transport in building barriers Richards model of unsaturated water flow can be distinguished. This model of water transport in porous materials can be seriously applied for capillary uptake simulations and can be useful to predict behavior of the walls which are prone to groundwater influence. One of the most important empirical parameters which are applied in the above mentioned model is hydraulic conductivity coefficient k, which, depending on type of water flow can be expressed in saturated state (saturated water conductivity coefficient ks) and water conductivity in relation to moisture for unsaturated water transport model. This article presents basic information about water transport models in saturated and unsaturated states that can be applied for prediction of capillary rise phenomenon in building barriers and determination of one of most important parameters – saturated water conductivity ks. Saturated water conductivity coefficient was determined for red ceramic brick, aerated concrete and autoclaved calcium silicate using a modified Wit apparatus, which normally is applied for soil hydraulic conductivity coefficient determination. Obtained results confirmed the lowest conductivity feature of red brick which is expressed in the lowest value of saturated conductivity coefficient. Aerated concrete and autoclaved calcium silicate are more porous materials and thus are more hydraulically conductive.