Calcium silicate hydrate (C–S–H) is the main cement hydration product, providing the most mechanical strength to concrete structure. As per the previous studies of bacteria-based self-healing concrete using non-ureolytic bacteria, one of the main issues is that the amount of externally added calcium salt was restricted by the properties of carriers, limiting the content of precipitated calcium carbonate. In addition, previous studies barely investigated the potential impact of microbial activities on the individual cement hydration products. Therefore, in this study, for the first time, we investigated the individual impact of bacteria on synthesised C–S–H gel and the potential of biomineralisation of C–S–H gel. In light of results obtained in this study, we evidenced that C–S–H could be biomineralised to produce a considerable amount of calcium carbonate. Decalcification of C–S–H gel and microbial carbon-capture were simultaneously occurred prior to the precipitation of calcium carbonate, resulting in increase of calcium and bicarbonate ions in the solution. The amount of precipitated CaCO3 is closely in response to Ca/Si ratio in C–S–H, higher Ca/Si essentially led to more precipitates, whilst the remaining structure and mass of C–S–H gel that could not be further biomineralised was generally similar.

水合硅酸钙 (C-S-H) 是主要的水泥水化产物，为混凝土结构提供最大的机械强度。根据以往对非脲解菌菌基自愈混凝土的研究，主要问题之一是外加钙盐的量受载体性质的限制，限制了沉淀碳酸钙的含量。此外，以前的研究几乎没有研究微生物活动对单个水泥水化产物的潜在影响。因此，在本研究中，我们首次研究了细菌对合成 C-S-H 凝胶的个体影响以及C-S-H凝胶的生物矿化。根据本研究中获得的结果，我们证明 C-S-H 可以生物矿化以产生大量碳酸钙。在碳酸钙沉淀之前同时发生 C-S-H 凝胶脱钙和微生物碳捕获，导致溶液中钙离子和碳酸氢根离子增加。沉淀的 CaCO3 的量与 C-S-H 中的 Ca/Si 比密切相关，较高的 Ca/Si 本质上会导致更多的沉淀物，而 C-S-H 凝胶的剩余结构和质量不能进一步生物矿化大体相似。