Sealing and unsealing effect of filamentous fungi in CEM I cement mortars with polycarboxylic admixture

Abstract

Biodeterioration may take place due to the influence of microorganisms, leading to the deterioration or destruction of materials. This process involves distinct mechanisms of material breakdown, such as mechanical damage, decomposition, corrosion induced by microorganisms, and fouling caused by living organisms. Research and literature data on biological corrosion of polymer-modified cement materials (polycarboxylate resin) are ambiguous and even contradictory. Samples, 20x20x160 mm in size, made of cement-polymer mortar with 5% polycarboxylate resin were prepared for the test, with 6 specimens for each determination. The study determined the level of contamination of the material, using the culture method and COD, after 18 months of exposure to Penicillium and Cladosporium fungi. In addition to this, bulk moisture content, water absorption, flexural strength and internal structure were determined using a scanning microscope and EDS analysis was carried out. The beneficial role of polymers has been demonstrated, e.g. by sealing the structure of cement-polymer materials. However, there is also an increased development of biocorrosion associated with organic material as a food source, especially for molds that colonize materials in favorable conditions. The test results showed that there was a strong growth of mold fungi on the material and the mass humidity was high. However, the strength increased slightly, and after further exposure to a corrosive environment it decreased again.