Phenomenological description of the effect of glass dissolution on cement paste evolution in an integrated glass dissolution experiment

Abstract

The interaction between nuclear glass surrogate and ordinary Portland cement (OPC) was investigated through integrated static leach tests conducted at ambient temperature. Tests were performed in stainless-steel cells in which OPC hydrated cement pastes were separated from glass powders by a stainless-steel filter. This article gives a phenomenological description of the processes affecting the hydrated cement paste arising from glass dissolution. The results show that the ingress of Si from glass dissolution leads to the degradation of the cement paste over a distance of 100–200 μm within 900 days of interaction. The Hardened Cement Paste (HCP) is affected by two main processes, which are the pozzolanic reaction and the alkali-silica reaction (ASR). These processes lead to porosity changes of HCP in contact with the stainless-steel filter and significant changes in the diffusive properties of the HCP. Especially, the effect of such processes on boron and lithium retention was studied and showed that precipitation of ASR-like gel and low Ca/Si C–S–H (Calcium Silicate Hydrate) highly retain these two elements. In the presence of an Al-rich glass (SM539), ASR is unlikely due to the preferential formation of C-A-S-H (Calcium Aluminium Silicate Hydrate).