Spatial zonation of a hydrotalcite-like phase in the inner product of slag: New insights into the hydration mechanism

The nano-structural evolution of the inner product of ground granulated blast furnace slag in blended cement at 7, 14, 28 56 and 180d was revealed. Three distinct layered inner hydration product region were observed because of the spatial zonation of hydrotalcite-like phase, CASH gel and Ca-Al LDH phase. The zonation of inner hydration product explains the presence of the multi-rims features of the slag grains with a relatively high reaction degree at very late ages. Diffusion of dissolved ion from slag grains and the effect of pore space on the reorganization of hydration products play a key role in forming the spatial zonation of inner hydration product. The findings of the zonation of inner region argue that the lack of pore space in the inner region makes the continued dissolution of slag hard to complete.

Automated summary

The nano-structural evolution of inner products of ground granulated blast furnace slag in blended cement was studied at various ages, revealing a spatial zonation of different hydration product regions. The zonation of inner hydration products explains the multi-rim features of slag grains at very late ages, with the lack of pore space hindering the complete dissolution of slag. Diffusion of dissolved ions and pore space play key roles in forming the spatial zonation of inner hydration products.