Thermal activation of concrete fines is a promising method for the simultaneous reduction of emissions and mineral waste. Hydrated cement paste, a major component of these recycled materials, can be used as a reactive supplementary cementitious material after dehydration at elevated temperatures and grinding. This affects concrete strength, especially when fines contain a higher proportion of aggregates. While strength loss can be mitigated by adjusting the water-binder ratio, the combined effect on other mechanical properties and durability remains unclear. This study utilizes seven different artificial concrete fines with varying binder compositions, aggregate contents, and aggregate mineralogies to produce concrete with varying compressive strengths. These concretes are then assessed for their flexural strength, elastic modulus, shrinkage, water absorption, chloride diffusion, carbonation, and freeze-thaw-resistance. Results highlight that with increasing compressive strength, mechanical properties and durability also improve. However, while strength development and the elastic modulus are similar to the reference concrete, the substitution of Portland cement through activated fines increases shrinkage as well as carbonation and chloride ingress, especially for fines with a high amount of reactive . • Concrete containing activated fines offers good mechanical and durability performance. • The substitution influences compressive strength and long-term behavior. • The impact differs with varying fines composition and processing. • The water-binder ratio may be used to compensate for changes in concrete properties.
Höffgen et al. (Sun,) studied this question.