Development of low carbon concrete through carbon (CO2) sequestration and waste valorization

Abstract

Carbon capture, utilization, and storage (CCUS) technologies in concrete production have recently gained widespread attention due to their ability to reduce global warming potential (GWP) significantly. It is considered the most significant avenue to utilize the captured carbon dioxide (CO2), with its capacity influenced considerably by various parameters, including the process adopted to introduce CO2 inside concrete. This investigation attempted to understand the effects of sequestration performed during mixing and curing stages on conventional and green binder added concrete types (through waste valorization) by utilizing state-of-the-art CO2 mixing and CO2 curing setups. A range of tests were performed to evaluate the physical, mechanical, microstructural, morphological, porosity, and durability-related properties of the specimens prepared using the various mixing-curing regimes. The CO2 sequestration potential was assessed and quantified for all the specimens (prepared using different binder types) at varying depths from the external surface, and the rate of CO2 conversion was evaluated for each. In addition, to determine the net environment and price benefits after using this technology, the life cycle analysis (LCA) was performed considering 16 concrete production processes, whereas the cost-benefit analysis (CBA) was done based on 14 cases. It was observed that a maximum CO2 uptake capacity of 25 % could be achieved under standard ambient temperature and pressure (SATP) conditions, with a maximum CO2 conversion of upto 70.35 % and 96.18 % achieved for CO2 mixing and CO2 curing, respectively. Additionally, the concrete’s strength got enhanced on account of thermodynamically stable calcite polymorph formation, along with microstructural densification, reduced pore size and a lesser chloride migration to provide an increased resistance against corrosion. Further, CO2 capture system installation in factories could potentially reduce more than 8.58 % of global CO2 emissions for all.