Influence of Lysinibacillus sphaericus on compressive strength and water sorptivity in microbial cement mortar.
| Autor: | Mutitu DK; Department of Physical Sciences, University of Embu, Embu, Kenya., Wachira JM; Department of Physical Sciences, University of Embu, Embu, Kenya., Mwirichia R; Department of Biological Sciences, University of Embu, Embu, Kenya., Thiong'o JK; Department of Chemistry, Kenyatta University, Nairobi, Kenya., Munyao OM; Department of Chemistry, Kenyatta University, Nairobi, Kenya., Muriithi G; Department of Physical Sciences, University of Embu, Embu, Kenya. |
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| Jazyk: | angličtina |
| Zdroj: | Heliyon [Heliyon] 2019 Nov 20; Vol. 5 (11), pp. e02881. Date of Electronic Publication: 2019 Nov 20 (Print Publication: 2019). |
| DOI: | 10.1016/j.heliyon.2019.e02881 |
| Abstrakt: | Cement structures are subject to degradation either by aggressive media or development of micro/macro cracks which create external substance ingress pathways. Microbiocementation can be employed as a self-intelligent solution to this deterioration process. This paper presents study results on the effects of Lysinibacillus sphaericus microbiocementation on Ordinary Portland cement (OPC), normal consistency, setting time, soundness, compressive strength and water sorptivity. Microbial solutions with a concentration of 1.0 × 10 7 cells/ml were mixed with OPC to make prisms at a water/cement ratio of 0.5. Mortar prisms of 160 mm × 40 mm x 40mm were used in this study. A maximum compressive strength gain of 17% and 19.8% was observed on the microbial prism at the 28 th and 56 th day of curing respectively. A minimum of 0.0190 and a maximum of 0.0355 water sorptivity coefficient was observed on the OPC microbial prism and OPC control prism, after 28 th day of curing respectively. Scanning electron microscope images taken after the 28 th day of curing showed formation of vast calcium silicate hydrates and more calcite deposits on microbial mortars. Statistical findings of this study indicate that Lysinibacillus sphaericus significantly retarded both the setting time and normal consistency, but has no influence on the mortar soundness. (© 2019 The Author(s).) |
| Databáze: | MEDLINE |
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