Paper by BERGIJK BAETENS from ISCR 9th 2004 Instanbul Turkey
In Western Europe the demand for a crack-free structure is not uncommon. Due to environmental reasons more and more (concrete) structures are built to prevent toxic liquids from leakage trough the structure to the subsoil and groundwater. These structures can be found for instance in the chemical industry, petrol stations, car maintenance garages and dump areas for waste material. Cracks in concrete, which occur in the hardening stage due to thermal stresses, can be a problem for liquid tightness of the structure. The hardening of concrete is accompanied by non-linear temperature distributions in the structure. If the thermal dilation of the structure is restrained, this will lead to cracks if the tensile stresses exceed the tensile strength of concrete. Liquids easily penetrate (fully) cracked concrete so a cracked structure is not capable to prevent liquids from getting into the soil or groundwater underneath the structure. Especially in case of toxic and therefore environmental dangerous liquids this can not be allowed. User-friendly numerical models have become available to predict the temperature development in young concrete as well as the risk of early-age cracking. Based on the numerical concrete concept a user-friendly module is developed that simulates the behaviour of young concrete. This article describes how this model is used to find measures to control concrete temperatures and thermal stresses. It is illustrated with a practical example of a concrete structure in the chemical industry in the Netherlands that has to protect the soil and groundwater for toxic liquids.