Bio-based CO2 sequestration in cementitious materials

Goal
The objective of this study is to achieve highly efficient CO2 sequestration in cementitious materials by employing biomaterials, while also ensuring concrete durability. Carbonation of cementitious materials occurs naturally, wherein CO2 from the atmosphere reacts with Ca(OH)2 to produce CaCO3. However, this natural process is inherently slow and influenced by many limiting factors. This project aims to accelerate the carbonation process in cementitious through the utilization of biomaterials that have been proven to be able to facilitate CO2 sequestration. The mechanisms by biomaterials that enhance CO2 sequestration need to be elucidated to facilitate their application in cementitious materials. The CO2 sequestration performance of the bio-modified cementitious materials needs to be evaluated. Optimization of experimental conditions and improvement of the biomaterials system are necessary for maximizing the potential of CO2 sequestration. The interactions between biomaterials and cementitious materials should be investigated to comprehend their impact on concrete durability. Additionally, the feasibility of scaling up CO2 sequestration of concrete structures using biomaterials will be explored.

Methodology
The biomaterials being considered for accelerating CO2 sequestration include enzymes, photosynthetic bacteria, and biopolymers. To evaluate the performance of CO2 sequestration, different carbonation conditions such as varying relative humidity and CO2 concentrations will be explored. Additionally, the impact of sample size, porosity, and chemical composition on the carbonation process will be examined. To quantify CO2 sequestration, thermogravimetric analysis (TGA) will be employed for analyzing the composition of cementitious materials, particularly the amount of CaCO3. BET surface area and scanning electron microscopy (SEM) can be used for analyzing the microstructure of the material. X-ray diffraction (XRD) will provide insight into crystal structures of different phases. In addition, mechanical strength tests will also be conducted to assess the structural integrity of the material. Furthermore, the durability properties of larger-scale samples will be assessed to evaluate their long-term usability. Overall, the methodology of this project will focus on factors such as carbonation conditions, sample characteristics, composition analysis, microstructure characterization, mechanical strength evaluation, and long-term durability assessment.