Mechanical, rheological, and durability performances of <scp>GGBS</scp> ‐based concrete for potential application to prestressed structures

Abstract Ground granulated blast‐furnace slag (GGBS) is a widely used clinker substitute in concrete, recognized for its potential to significantly reduce environmental impacts. However, its application in prestressed concrete remains limited in several countries, mainly due to concerns regarding early‐age mechanical performance and long‐term durability. This study addresses this gap by specifically evaluating the feasibility of high‐GGBS concretes for prestressed structural applications through an integrated assessment of mechanical, rheological, and durability properties. The novelty of this work lies in: (i) its explicit focus on concretes suitable for prestressed elements and (ii) the combined evaluation of mechanical performance and durability‐related properties within a unified experimental framework representative of current construction practice. This experimental evidence is essential for supporting the revision of existing guidelines and standards, enabling the safe adoption of high‐GGBS concretes in prestressed structural elements and expanding their use in more sustainable infrastructure. The study involves the experimental characterization of eight mixtures, incorporating GGBS cements with a slag content ranging from 39% to 70% (classified as CEM III/A and /B according to EN 197‐1) and compressive strengths between 30 and 45 MPa, thereby providing insights relevant to both reinforced and prestressed concrete applications, using commercially available cements and concrete mix designs representative of current construction practice. The results demonstrate that GGBS concretes meet the early‐age strength requirements for prestressed applications and exhibit superior long‐term performance compared with traditional Portland cement. In present tests, no evidence of corrosion initiation attributable to the sulfides provided by the material was observed under the testing conditions despite the relatively high concentration of them in the slags. High GGBS contents enhance resistance to chloride penetration, water absorption, and electrical resistivity. However, the increased carbonation rates found necessitate careful consideration in environments prone to carbonation‐induced degradation. These findings highlight the potential of GGBS‐based concretes as viable materials for prestressed structures, particularly in applications prioritizing sustainability and resistance to chloride‐rich exposures.