Energy consumption, carbon emissions and cost analysis of accelerated curing: A case study of hybrid alkali-activated cement

With the development of prefabricated buildings, accelerated curing has become an effective way to achieve rapid strength growth of concrete, however the energy consumption and environmental benefits of this process have rarely been evaluated. Hybrid alkali-activated cement (HAAC) is considered as a potential material for replacing Portland cement (PC) because of its excellent mechanical properties and low carbon emissions. In this study, HAAC consists of 80 % granulated blast furnace slag (GBFS), 20 % PC and 3.7 % alkali activator, and conventional alkali-activated materials are prepared as a reference sample. The influence of curing temperature (20, 45, and 70 °C) on strength and microstructure development of HAACs are investigated, and the energy consumption during curing is evaluated. The results showed that adding an appropriate amount of PC and increasing the curing temperature reduced the setting time of mixture. HAACs also exhibited higher compressive strength than alkali-activated materials without PC, and the appropriate growth of curing temperature was beneficial to the strength development of samples. In the curing process, the energy consumed by the high temperature curing of 45 °C was relatively increased by 11.96–12.14 kWh/m3 compared with the normal temperature curing (20 °C), but the strength gain reduced its economic and environmental loads by 11.15–11.90 % and 10.75–11.68 % respectively compared with normal temperature-cured sample. This study discusses energy efficiency of accelerated curing in the production of HAAC, which provides an optimal energy utilization strategy for producing precast cement-based materials.