Development and experimental validation of an overlay mortar with biocide activity

Abstract

Biodeterioration of concrete by microorganism colonisation may be a problem in several structures, especially in irrigation and hydroelectric canals. The main problem in such structures is the proliferation of algae and cyanobacteria that affect the performance of the structure, increase the maintenance costs and affects its durability. A research was conducted to develop a novel cement-based material with biocide activity that can be used as an overlay mortar in existing structures, such as canals and pipes. With this aim, ten commercial biocides were evaluated in a laboratory campaign to assess the effectiveness of the compounds against the microbial colonisation of concrete. Both mono- and multicomponent formulations were designed from the commercial products, to increase their antimicrobial effect obtaining a set of biocide formulations. The formulations were submitted to a flowchart process to determine their influence on the physical properties of the concrete, evaluate the release of the actives, and their antimicrobial efficiency both before and after accelerated aging processes. During the campaign, some formulations were observed to diminish the strength of the concrete. Such behaviour was normally due to the interaction of the active with the cement hydration process. Other formulations showed a high release of active from the concrete in water, compromising the durability of the treatment. In general, monocomponent formulations did not succeed to fulfill all the requirements, thus multicomponent formulations were analysed. One studied multicomponent formulation presented particularly good results in all properties analysed. This product did not significantly change the properties of concrete and the release of active in water from the concrete was low, while the antimicrobial effects were long lasting.Peer ReviewedPostprint (author's final draft

Antimicrobial concrete for smart and durable infrastructures: A review

“…[14] , [15] . Bio-deterioration of concrete in irrigation and hydroelectric canals [16] , spots or patches covered on concrete walls [17] , and biological decay of mortars on building facades [18] commonly result from the growth of algae and cyanobacteria. Algal growth is also quite common on concrete walls of water storage and conveyance structures [19] .…”

“…Salmonella, an important foodborne pathogen, are easily attached and colonized on surfaces of concrete used in food industry due to their adherence forming biofilms [20] . The propagation and proliferation of microorganisms including bacteria (e.g., pathogens), fungi, and algae alone or together, on and/or in concrete structures, will affect concrete’s aesthetic appearance, destroy the internal structure of concrete, degrade mechanical properties and durability of concrete, increasing the cost by rehabilitation and even replacement [2] , [16] , [21] , [22] , [23] . Therefore, developing antimicrobial concrete for smart and durable infrastructures has become extremely significant and imperative.…”

“…Moreover, it is reported that antimicrobial concrete containing Zeomighty (zeolites with silver and copper ions) was introduced on the Japanese market [33] . Quaternary ammonium compounds (Quats) have been used as antimicrobial agents for a long time, and only recently they have been reported to be effective as algaecides [11] , [16] , [19] , [34] . Intentionally, considering the severe consequences caused by microbial induced corrosion of concrete, considerable attention has been paid to find effective antimicrobial agents to admix into concrete in order to fight against Thiobacill [3] , [23] , [35] , [36] .…”

Evaluating the efficacy of antimicrobial additives against biogenic acidification in simulated wastewater exposure solutions

“…Several strategies have been proposed to prevent or slow down the degradation due to MICC. These strategies include improving the hydraulic design and ventilation of wastewater networks, enhancing concrete resistance to sulfuric acid, use of supplementary cementitious materials, geopolymers, calcium aluminate cements and colloidal silica, using polymeric liners and other coating techniques, biocide addition to wastewater to reduce the activities of SRB, and preventing the growth of SOB using antimicrobial additives for concrete as admixed or topical treatment [13,[20][21][22][23][24][25][26][27][28]. Each prevention strategy has benefits and potential costs.…”

Development of conductive cementitious materials using recycled carbon fibres

“…Recently, energy-harvesting tiles were used during the Paris marathon of 2013 and helped to produce 4.7 kWh of energy (4). Current research trends in smart cementitious materials include self-healing concrete (5,6), enhanced bioreceptivity concrete (7,8), mortars with biocide characteristics (9), and development of conductive cementitious materials.…”