Influence of Starkeya novella on Mechanical and Microstructural Properties of Cement Mortars
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Date
2020
Authors
Munyao, Onesmus Mulwa
Thiong’o, Joseph Karanja
Wachira, Jackson Muthengia
Mutitu, Daniel Karanja
Mwirichia, Romano
Journal Title
Journal ISSN
Volume Title
Publisher
Hindawi
Abstract
Cement-based materials are subject to degradation during their service life. Most of the structural failures have been associated
with corrosion of the rebar due to chloride ingress, alkali aggregate reaction, and/or sulfate attack. Microbial activities, especially
in waste water collection points such as sewer lines, may compromise the integrity of concrete structures. (is study reports an
experimental work carried out to determine the effect of Starkeya novella bacteria species on mechanical and microstructural
properties of cement mortars. Mortar prisms were prepared from selected ordinary Portland cement (OPC) and Portland
pozzolana cement (PPC) in Kenyan markets. Bacterial solution of 1.0 ×107 cell/mL concentration was used as either mix water,
curing media, or both. Distilled water was used to prepare mortar prisms for control samples. Compressive strength was determined
after the 7th, 28th, 56th, and 90th day of curing. Scanning electron microscopy (SEM) was tested on both bacterial and
control mortar prisms after the 28th day of curing. Both PPC and OPC exhibited significant decrease in compressive strength for
bacterial-prepared mortars as compared to controls. SEM analysis showed extreme erosion on the microstructure of the microbial
mortars. (is was denoted by massive formation of ettringite and gypsum which are injurious to mortar/concrete.
Description
A research article published in Journal of Chemistry
Keywords
Starkeya novella, Cement Mortars
Citation
Munyao, O. M., Thiong’o, J. K., Wachira, J. M., Mutitu, D. K., & Mwirichia, R. (2020). Influence of Starkeya novella on Mechanical and Microstructural Properties of Cement Mortars. Journal of Chemistry, 2020.