Use of Sustainable Antimicrobial Aggregates for the In-Situ Inhibition of Biogenic Corrosion on Concrete Sewer Pipes

Abstract

A new generation of cementitious materials is being engineered to selectively inhibit the growth of Acidithiobacillus, which are a key genera of acid-generating bacteria responsible for microbially induced concrete corrosion (MICC). In this context, the substitution of metal-laden granular activated carbon (GAC) particles and/or steel slag for a fraction of the fine aggregates traditionally used in concrete mixture has proven useful. While the antimicrobial properties of specific heavy metals (i.e. copper and cobalt) have been leveraged to inhibit acid-generating bacteria growth on sewer pipes, few studies have researched how biocidal aggregates may affect the microstructural and mechanical properties of cementitious materials. We report here on the effects that these biocidal aggregates substitutions can have on compressive strength, flowability, and setting times of cement-based formulations. Results showed that increases in compressive strength, regardless of the presence or absence of biocidal metals, resulted from the GAC incorporation where sand replacement was 3% by mass or lower, while flowability decreased when percentages higher than 3% of GAC was incorporated in a cement mix. When substituting fine aggregate with steel slag particles in mass ratios between 5% and 40%, compressive strength was not affected, regardless of the presence or absence of copper. Setting times were not affected by the inclusion of GAC or steel slag particles except when substituting GAC particles at 10% of the fine aggregate mass; under this condition both initial and final setting times were decreased. Results suggest that in order to have enhanced inhibition potential against acidophilic microorganisms and equal or improved mechanical properties, a combination of 1% metal-laden GAC and 40% copper-laden steel slag is an optimum fine aggregate substitution scenario.

Development of Antibacterial and Antifouling Innovative and Eco-Sustainable Sol–Gel Based Materials: From Marine Areas Protection to Healthcare Applications

“…They investigated the effect on microbial growth by applying different coatings between the concrete and the pipes surface obtained from the adding of zinc particles or zinc doped clay particles, demonstrating a higher resistance to the degradations concerning the ordinary cement-based and geopolymer-based coverings. Justo-Reinoso et al suggested replacing fine aggregates traditionally used in cement mixtures with granular activated carbon and fundamental oxygen furnace steel slag particles, copper, and cobalt as inhibitory metals towards the acidogenic microbial development in concrete sewer pipes [ 49 ]. This study also described improved mechanical properties, such as compressive and flexural strength for the cement-treated, concerning the conventional ones.…”

Influence of copper-impregnated basic oxygen furnace slag on the fresh- and hardened-state properties of antimicrobial mortars

“…BOFS, either in powder or granular form, have been included in cement formulations for various purposes [2,[4][5][6][7]. One emerging application of BOFS in its granular form concerns metal-impregnated BOFS particles that have been used as a new class of antimicrobial admixture for inhibiting microbially induced concrete corrosion (MICC) [8][9][10].…”

“…Within recent years, antimicrobial admixtures containing different heavy metals have been increasingly used in conventional concretes in efforts to stem MICC proliferation [11,16]. Two specific carriers have been previously reported for this metal-delivery purpose: zeolites [17,18] and activated carbon [9,10,15,19,20]. In this context, the use of 3 copper-laden BOFS particles in cementitious materials represents a promising new approach to inhibit the microbes responsible for biogenic corrosion [8][9][10].…”

“…Two specific carriers have been previously reported for this metal-delivery purpose: zeolites [17,18] and activated carbon [9,10,15,19,20]. In this context, the use of 3 copper-laden BOFS particles in cementitious materials represents a promising new approach to inhibit the microbes responsible for biogenic corrosion [8][9][10]. Even though the incorporation of copper-laden BOFS particles in cementitious materials has demonstrated a potent antimicrobial effect [8], how these BOFS inclusions specifically influence cement hydration and the mechanical properties of concrete remains unknown.…”

“…In recent years, due to increased environmental concerns and more restrictive regulations regarding the extraction and use of natural aggregates for the concrete industry, the feasibility of using particles as fine aggregate substitutes has been investigated [5][6][7]9]. The effects that BOFS have on principal mechanical properties of cementitious materials, following fine aggregate substitutions have been documented.…”