A new test method to assess the bacterial deterioration of cementitious materials

Review of Concrete Biodeterioration in Relation to Buried Nuclear Waste

“…Surface contact onto concrete by bacterial biofilms (discussed in some detail below) increases the concentration of degrading metabolites to a greater degree than just soluble chemicals alone, resulting in an increase of concrete degradation deeper into the matrix [9]. This is the reason that chemical tests alone do not adequately estimate microbial damage to concrete [68].…”

“…In addition rock-inhabiting fungi demonstrate enough mechanical strength in their hyphae to penetrate into crevices for nutrients. Fungi in this case, especially those that produce melanin, which confers extra-mechanical strength, can rapidly penetrate millimeters to centimeters into concrete-like structures [9,53,60]. Fungi also can produce peroxide, by the enzyme peroxidase.…”

“…Since then, biodegradation of concrete structures was demonstrated to be a common occurrence; however, various microbial populations and mechanisms were shown to play different roles at different locations [5][6][7]. As a result, microbial assays designed to determine the rate of concrete biodegradation proved useful in evaluating concrete properties but were not a good predictor of environmental impacts on concrete [8,9]. Specific environmental conditions to which concrete is exposed, at any given location must be considered in order to understand environmental impacts on concrete biodeterioration [10].…”

Preliminary study on the size effect of composite materials subjected to bending

“…Deterioration may be the result of design errors, material incompatibilities [1], industrial or farming waste, agro-food and breeding waste waters [2], seawater attack, carbonation, unexpected loads, vibration, repeated freezing and thawing, and the application of de-icer salts throughout winter. Concrete deterioration due to seawater attack ( Figure 1) can lead to a dimensional change of concrete sections and then a reduced strength or load carrying capacity of the concrete structure, in terms of ultimate moment.…”

Fungistatic Properties of Granulated Blastfurnace Slag and Related Slag-Containing Cements

“…Biogenic high-molecular organic acids, such as humic acid or pyruvic acid, and biogenic low-molecular organic acids, such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, oxalic acid, malic acid, citric acid and others [4,5], are formed by the activity of certain chemoorganotrophic bacteria and fungi. In some cases the chemical corrosive effect of organic acids is even higher than that of H 2 SO 4 [6].…”