Effects of Bacillus subtilis biocementation on the mechanical properties of mortars

  • Nicole Schwantes-Cezario PhD student at State University of Londrina.
  • Maria Fernanda Porto Master student at State University of Londrina
  • Geovana Souza Ferreira Nogueira Master student at State University of Londrina
  • Gersson Barreto Sandoval PhD student at State University of Londrina
  • Álisson Franco do Couto PhD student at State University of Londrina
  • Berenice Martins Toralles Professor at State University of Londrina

Abstract

This study aims to evaluate the influence of B. subtilis AP91 spores addition on the mechanical properties of mortars. B. subtilis strain AP91, isolated from rice leaves of the needle variety, which has an early cycle of production, was used at the concentration of 105 spores/mL in mortars with cement-to-sand ratio of 1∶3 (by weight) and water-to-cement ratio (w/c) of 0.63. These spores were added in two different ways: in the mixing water and by immersion in a solution containing bacterial spores. Scanning Electron Microscope (SEM) analysis showed crystals with calcium peaks on the EDS, which possibly indicates the presence of bioprecipitated calcium carbonate. The results obtained in the mechanical analysis showed that the bioprecipitation of CaCO3 by B. subtilis strain AP91 was satisfactory, particularly when the spores were added in the mixing water, increasing the compressive strength up to 31%. Thus, it was concluded that the addition of B. subtilis AP91 spores in the mixing water of cement mortars induced biocementation, which increased the compressive strength. This bioprecipitation of calcium carbonate may very well have other advantageous consequences, such as the closure of pores and cracks in cementitious materials that could improve durability properties, although more research is still needed on this matter.
Published
Feb 5, 2019
How to Cite
SCHWANTES-CEZARIO, Nicole et al. Effects of Bacillus subtilis biocementation on the mechanical properties of mortars. RIEM - IBRACON Structures and Materials Journal, [S.l.], v. 12, n. 1, feb. 2019. ISSN 1983-4195. Available at: <http://revistas.ibracon.org.br/index.php/riem/article/view/1180>. Date accessed: 26 apr. 2019.
Section
Artigos