X-ray diffraction study on microbial calcite precipitation in concrete with Bacillus subtilis and Bacillus halodurans

Abstract

The X-ray diffraction (XRD) technique is a highly accurate tool for determining the hydration of cementitious materials, involving time-resolved quantitative analysis with acceptable accuracy with the sample. This paper discussed microbial calcite precipitated cement hydration. In the first part, the various literature related to XRD were studied, the various experimental plans were discussed, and the proper method for testing the bio-concrete was selected. The conventional samples were compared with the bio-concrete samples. The Bacillus family bacteria, which precipitate the calcite, were chosen for the testing in this study Bacillus subtilis and Bacillus halodurans are used for determining the amount of calcite precipitation and cementitious components. In the presence of bacteria, the performance of cement hydration was studied. The features and drawbacks of this approach were also discussed. We can conclude that the choice of a suitable experimental setup with accurate data and a short measurement time, appropriate evaluation of various unstructured and limitations in the XRD diffraction analysis, and an effective data analysis for the periodic critical factors for an effective analysis. It is strongly recommended that independent techniques be used to augment the bio-concrete XRD data. Using such a suitable data analysis routine progresses, consistency of time-resolved studies and affects operator variability while avoiding unrealistic results. We studied about the global and phase parameters that are needed for data analysis. The C3S-C3A-gypsum paste was compared during the first 48 h of hydration. The components are reviewed with reasoning. The microbial induced calcite precipitation is tested and the components are reviewed and compared with conventional. After the testing, the viability of the bacteria was evaluated. Using a SEM (Scanning electronic microscopic) model, the amount of precipitation was assessed. This study involves the microstructural analysis of bio-concrete and conventional ones. In the XRD analysis, the sizes of nano particles like calcite and C–H-S were determined and compared. The main objective is to calculate the amount of CaCO3 present in the bacterial concrete and to know which species precipitate more amount of CaCO3.