Hajduczek et al. (2026): In Situ Raman Spectroscopy of a Silica Gel-Templated Hydration Pathway in CO₂-Activated Cement
Marcin Hajduczek, Yogiraj Sargam, Sean Monkman, Vishnu Chaudhari, Santiago El Awad, Franz-Josef Ulm and Admir Masic, IN: Journal of the American Ceramic Society, https://doi.org/10.1111/jace.70825
This study investigates early-age carbonate mineralization in cementitious systems using in situ Raman microspectroscopy. In the presence of dissolved CO₂, clinker phases undergo accelerated dissolution, decomposing to form various calcium carbonate polymorphs and a transient amorphous silica gel network. Once the available CO₂ is consumed, clinker hydration resumes, leading to delayed calcium–silicate–hydrate (C–S–H) and portlandite (Ca(OH)₂) formation. The precipitation of portlandite through the pore network triggers a localized pozzolanic reaction at the silica gel–portlandite interface, yielding a distinct calcium–silicate–hydrate (C–S–H*). This templated mechanism produces a homogeneous and highly polymerized binder, leading to improved 24-h compressive strength compared to reference samples.