C-S-H/PCE nanocomposites modified limestone calcined coal gangue cement: Early-age properties and life cycle assessment

S-H/PCE nanocomposites (CPNs) have been demonstrated to be effective seeding additives, capable of promoting the early performances of cement-based materials. This study investigates the enhancing effect of CPNs on the properties of limestone calcined coal gangue cement (GLC3). Cement was replaced by 30 wt% calcined coal gangue and 5 wt% limestone in combination in GLC3 binder, and the investigated CPNs were 1.0 wt%, 2.0 wt%, 3.0 wt% and 4.0 wt%. The compressive strength, hydration kinetics, phase assemblages, pore structure and microstructure were characterized from macroscopic and microscopic scales. Furthermore, a life cycle assessment (LCA) of these mixes was also conducted using Simapro software. The experimental results showed that CPNs favors the compressive strength development of GLC3, especially at early stages. The GLC3 mortar, with 2.0 wt% CPNs, demonstrated enhanced early (8h-3d) and late (7–28d) compressive strength, ranging from 15% to 18% and 12–11%, respectively. With CPNs being added, the cement hydration and the reaction of calcined coal gangue were promoted, leading to an increase in the formation of more hydrates, enhanced refined porosity, and a more densified microstructure of GLC3. LCA indicates that the addition of 2.0 wt% CPNs can further decrease the global warming of GLC3 by 7.95%, indicating that the sustainable potential of CPNs in improving the performance of GLC3 is significant. The findings of this study provide a theoretical basis for the production of environmentally sustainable binders (prepared by solid waste and CPNs in combination) that exhibit acceptable performance.