Franco Zunino

Ultra-green concrete  (UGC)

The project aims at developing a new family of concretes (UGC: ultra-green concrete) to radically reduce the CO₂ emissions related to this material, substantially beyond the CO₂ savings of any of the technologies currently available. The project approaches the development of UGC with a novel and innovative two-fold strategy, moving the field of cement and concrete science far beyond its current state-of-the-art to achieve the ambitious carbon-reduction target:

1. Reduce the amount of clinker in cement substantially below 50%, maximizing the use of mineral additions such as calcined clay and limestone and others  through a fundamental understanding of reaction kinetics and hydrate precipitation that contributes to reduce porosity.
2. Reduce the amount of binder (hydrated paste) below 250 kg/m³ per cubic meter of concrete.

Limestone calcined clay cements (LC³)

LC³, blended cement produced by the combination of limestone, calcined clays and Portland cement provides a solution that achieves equivalent mechanical performance to OPC (Type I/II), better durability against chloride and ASR and a reduction of CO₂ emissions by about 40%. Furthermore it is cost effective, and due to the similarities with OPC it is a material that can be adopted today using the same construction equipment and workforce worldwide. Among his contributions of Dr. Zunino to the LC³ technology, establishing a mechanism of sulfate requirement in blended cements and a detailed description of the microstructural development of LC³ can be considered landmarks of his work. Currently, Dr. Zunino remains active in the LC³ research team, actively participating in education and dissemination activities organized in different regions of the world.

Hydration and phase assemblage of Portland limestone cements (PLC)

Limestone, while mostly inert, provides excellent nucleation surfaces for the precipitation of hydrates, and in some cases may positively contribute to the workability of the material. Nowadays, these cements are more common than conventional Type I/II Portland cements. Furthermore, the widespread availability of limestone makes these cements ideal candidates for scaling up replacement of clinker beyond what is feasible with just limestone with other locally available materials. This is for example happening currently in the USA, switching from Type I/II  to almost exclusively Portland limestone cements (Type IL in ASTM C595), roughly saving 10% of CO₂ relative to the previous situation where OPC was dominant.