CBL - Campus del Baix Llobregat

Projecte llegit

Títol: Elaboració d'un morter sostenible i autoregenerable a partir de residus minerals i bacteris.

Estudiant que ha llegit aquest projecte:

Tutor/a o Cotutor/a: CLARAMUNT BLANES, JOSEP

Departament: DEAB

Títol: Elaboració d'un morter sostenible i autoregenerable a partir de residus minerals i bacteris.

Data inici oferta: 16-01-2024      Data finalització oferta: 16-09-2024

Estudis d'assignació del projecte:
    GR ENG SIS BIOLÒG 23

Lloc de realització:
EEABB

Segon tutor/a (UPC): CENDRA GASCON, MARIA DEL MAR

Paraules clau:
Ciment, Guix, Autoreparable, Bacillus subtilis, fibra.

Descripció del contingut i pla d'activitats:
La crisi ambiental actual ens situa en un context crític on sorgeix la necessitat d'abordar reptes associats amb els processos industrials tradicionals, els quals han deixat un gran impacte climàtic i han generat, i continuen generant, grans volums de residus diàriament. En aquest sentit, el sector de la construcció és el responsable de més del 30% de les emissions equivalents de CO2 a nivell mundial, juntament amb una producció de residus sòlids superior al 20% dels residus mundials.

En resposta a aquesta problemàtica, es proposa la formulació d'un morter cel·lular biològic, mitjançant l'ús de residus de la indústria extractiva d'àrids i de la indústria tèxtil (constituint una matriu de fibres que millora les propietats físiques). Aquest enfocament, no només optimitza la dependència de matèries primeres no renovables,
sinó que també promou la circularitat de recursos l'àmbit industrial, centrant-se en la reutilització de recursos i la valorització de residus.

' El contingut d'aire en el ciment mitjançant un agent escumant, proporciona propietats d'aïllament tèrmic, acústic i d'humitat en un mateix material, eliminant la necessitat de recobriments addicionals i, per tant, simplificant el procés constructiu.
' La inclusió de bacteris és un element clau, ja que disminueix la necessitat de noves extraccions i proporciona la capacitat regenerativa del mateix material.

Aquesta proposta no només modifica els mètodes tradicionals de producció de ciment, sinó que també respon a la urgència de canvis en els processos productius actuals.
És un projecte amb un enfocament pioner, que representa un pas necessari capa a una construcció sostenible, amb llarga vida útil i que respon a la responsabilitat ambiental.

Overview (resum en anglès): The construction industry is one of the sectors with the greatest environmental impact. The production of concrete requires large amounts of energy and generates high CO¿ emissions, contributing to climate change in great magnitude. The main objective of this work was to develop a self-repairable cell concrete tile, inoculated with the Bacillus subtilis bacteria, reinforced with fibers, in order to reduce the need for maintenance and, therefore, a lower production of new material for the repair of structures over time.
Due to its design, several trials were carried out, the results of which determined the final focus of the study. First, a trial was carried out to determine the dose of foaming agent necessary to obtain the desired porosity in the concrete matrix. Viability tests of Bacillus subtilis were also carried out in the extremely alkaline environment of a cement solution. The trials carried out did not offer the desired results; the doses of foaming agent did not provide the desired porosity within the concrete matrix, so we discarded the hypothesis of making the concrete tile cells. On the other hand, the high pH of cement inhibited bacterial viability over a week of inoculation. As a result, a trial was carried out to reduce the pH of the cement by adding silicon smoke and, at the same time, the viability of Bacillus subtilis at various pHs was verified. From these last trials it was determined that silicon smoke was not enough to alter pH, although bacteria were viable at pH of 9 and 10. After obtaining the unexpected results, the initial hypothesis was reformulated, so the main objective of the work was the elaboration of a self-repairing gypsum tile reinforced with fiber. This change in the matrix's raw material was due to the neutrality of the pH of the gypsum, which does allow the development and metabolic activity of Bacillus subtilis, which was tested through feasibility trials of the bacterium in a gypsum solution.
For the realization of gypsum tiles, five samples were made, of three replicas each, with different concentrations of inoculation. Once they were prepared they were subjected to two flexion tests, one in June and another in September, thus obtaining two deformation-tension curves, which provided us with information on the behavior of the material, both before and after the regeneration period of 56 days. The comparison of these trials determined that the concentration of 2*¿10¿^5 ufc involved a large increase in the mechanical resistance of the material. Higher and lower concentrations than the above meant an increase in the minimum resistance, so the effectiveness of inoculation has been demonstrated as long as it is done through controlled concentrations.
In conclusion, this plaster inoculated with Bacillus subtilis is a promising option as an innovative material in construction, however, there is an extensive study ahead of it in order to optimize the viability of the bacteria within the matrix and accurately determine the optimal dose of inoculation.

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