Issue 59

M. A. R. Elmahdy et alii, Frattura ed Integrità Strutturale, 59 (2022) 486-513; DOI: 10.3221/IGF-ESIS.59.32

Figure 31: SEM images (3000X) after 90 days of curing for mixes (A) M0, (B) M12, (C) M13, (D) M8 and (E) M6.

E NERGY DISPERSIVE SPECTROMETER (EDS)

n order to confirm the analysis, some mixes were tested in EDS to check the peaks of the chemical elements present in the sample as well as the formation of calcite. Calcium carbonate (C), Oxygen (O), Aluminium oxide (Al), Silicon dioxide (Si) and Wollastonite (Ca) are considered to be the main elemental components of mortar mixes. Also, the EDS result shows that the precipitate is composed of atoms of Ca, C, and O which verifies that the precipitate is calcium carbonate. EDS test results are shown in Fig.32 and Tab. 12. EDS results show that all specimens have calcium peaks, but the peaks are more when the bacteria spores are added and when bacteria content increases it increases more. For example, using 2.5% bacteria BM compared to control mix, calcium carbonate increased by 48.4%, while 46.8% increased when using the EMCC content. When bacteria FP are used, the increase in calcium carbonate content compared to control mix is 10.85% and 22.59% when used with content of 0.5% and 2.5%, respectively. The ratio of atomic% of Ca/Si for tested mixes is one of the main indicators that has been observed. By increasing the ratio, it indicates that the mixture has a low compressive strength. For instance, the ratio of atomic% of Ca/Si for control mix M6 was 0.52 when was 3.7 for control mix M0. These results are congruent with what has been reported by other researchers. [15,22,43]. I

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