Improved flowability and strength using carbonated BOF slag and potassium citrate in sustainable LC3 binder

This study proposes a sustainable LC3 binder incorporating calcined low-grade clay, carbonated basic oxygen furnace slag (Cs), and potassium citrate (citrate) as a ternary cementitious system. Cs and citrate replace limestone powder (Ls) and polycarboxylate superplasticizer (SP), respectively. Citrate enhanced flowability while extending the hydration induction period, achieving up to a 9.1% increase in flow. Compared with SP-modified LC3, citrate improved compressive strength by 6.8–11.8%, while Cs incorporation further increased 28-day strength by up to 29.7%. Microstructural analyses revealed reduced porosity, refined pore structure, lower portlandite content, and increased C-S-H formation due to enhanced pozzolanic reactions. Life cycle assessment showed that Cs blends reduced CO 2 emissions and energy consumption by approximately 19%, demonstrating their potential as high-performance, low-carbon binders. • Cs improves hydration, lowering energy use by 19.2 % compared with LC3. • Citrate acts as both a water reducer and activator, enhancing flowability over SP. • Cs and citrate substantially increase 28-day strength by29.7 % and 6.8–11.8 %, respectively.