Biodeterioration of Mortars and Cement Paste studied using ESEM, STEM and EDS

Concrete, a widely used material in civil engineering, suffers from weathering. Among the known weathering factors, biological factors are often neglected in spite of their synergistic action with chemical and/or mechanical factors. This article is about a method developed to study the bioalteration of concrete. ESEM observations and EDS analyses of mortar samples immersed for three years in the Rhine ground water table revealed the presence of deposits showing micro-organisms. The first tests on ultrathin sections of mortars examined using STEM show the potential and the value of continuing such analyses in order to evaluate the bioreceptivity of concrete.