Cement-on-a-chip: a microreactor for operando studies of the carbonation curing of cementitious materials

Owing to the high carbon emissions associated with the production of Portland cement clinker and its use in concrete, the construction industry is interested in the development of more sustainable materials and processes. One area of research is on the curing of cements through carbonation rather than hydration in order to offset emissions by sequestering CO₂ in the built environment. Here, we present a simple 3D-printed gas-flow microreactor to facilitate rapid studies of the carbonation curing of millimeter-thin cement samples (also known as carbon curing or CO₂ curing). The device is paired with a gas and humidity control system to deliver precise environmental conditions. It can be coupled with various analytical techniques, including X-ray diffraction and Raman spectroscopy, thus allowing in situ monitoring of carbonation processes. We validate and characterize the carbonation system and measurement sensitivity and subsequently utilize the microreactor to investigate a large parameter space in the carbonation curing of a hydrated lime model system. Finally, we demonstrate the potential industrial utility of the device by following the carbonation curing of ordinary Portland cement (OPC) paste.