Influence of Enterococcus faecalis and Bacillus sp with added calcium lactate on engineering concrete properties and enhancement of self healing in concrete under unsterillized condition

Concrete is one of the most used construction material in the world. The constant development and research for better concrete has led to bioconcrete, which is concrete infuse with micro-organisms that benefits the concrete by production of calcium carbonate. However, the production of calcium carbo...

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Bibliographic Details
Main Author: Luis Hii, Anneza
Format: Thesis
Published: 2017
Subjects:
Online Access:http://eprints.uthm.edu.my/9850/
http://eprints.uthm.edu.my/9850/1/Anneza_Luis_Hii.pdf
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Summary:Concrete is one of the most used construction material in the world. The constant development and research for better concrete has led to bioconcrete, which is concrete infuse with micro-organisms that benefits the concrete by production of calcium carbonate. However, the production of calcium carbonate is limited to the calcium available in the cement. Therefore, the purpose of this study is to add calcium nutrient source in the form of calcium lactate in bioconcrete and study the engineering concrete properties and self-healing of micro-cracks. The bacteria used in this study is 3% Enterococcus faecalis and 5% Bacillus sp. Whereas the calcium lactate that is added into this study is in concentrations of 0.22 g/L, 1.09 g/L and 2.18 g/L. Concrete with dimensions of 100 mm × 100 mm × 500 mm for prisms, cylinders of 150 Ø × 300 mm and cubes of 150 mm × 150 mm ×150 mm are used to test for the engineering concrete properties at 7th, 14th and 28th day and self-healing of micro-cracks in concrete is in the range of 0-100 days. This research has contributed significantly to the finding of overall improvement of concrete properties from the addition of calcium lactate in bioconcrete. This is confirmed with the improvement of engineering concrete properties and self-healing of micro-cracks with the addition of 2.18 g/L of calcium lactate for both bacteria. UPV and micro-structure analysis were conducted to verify self-healing. Based on overall results, concrete with Bacillus sp with 2.18 g/L is most ideal.