Bruno Huet has over 20 years of R&D experience both in industry and academia, working on carbonation of cement based materials. After an engineering degree from INSA Lyon, he focused on steel corrosion in carbonated concrete at the French Atomic Commission for his doctoral degree. As a research assistant at Princeton University he focused on reactive transport modeling of cement sheath for CO2 storage application. He then moved to Schlumberger Carbon Services developing wellbore integrity models and solutions in addition to extending reservoir flow model to CO2 mineralization options. Now with Holcim for the past 10 years, he’s focusing on hydration and carbonation of standard and alternative cement from manufacturing to durability in products. He’s using both experimental measurements and numerical models as tools to assess product physical and chemical properties as well as their performance, bridging the gap between science and applied engineering, products and processes. He’s a member of various RILEM Technical committees (TC) and secretary of TC GDP on gas diffusion in porous media.
Low clinker systems: towards rational uses of SCMs for optimal performance
Clinker replacement by other SCMs is the second-largest contributor to reduced emissions, after carbon capture technologies, according to The GCCA roadmap. However, most producers are still far from the 60% clinker factor as of 2022. Optimizing SCM use and lowering the clinker factor below 60% will be far more cost effective than relying so heavily on carbon capture despite their importance in the roadmap. Each SCM type adds a different filler and chemical effect to the cement reaction and contributes differently to the development of performance. They influence C-S-H formation, morphology, and chemical composition, as well as cement and concrete properties at different ages. An optimized use of the cement components through optimized PSD and content will avoid lasting with large amounts of unreacted particles that will not contribute to the concrete mechanical and durability performances when placed. Additionally, it can avoid excess of extremely fine materials that are very reactive but need in turn more water demand of concrete leading to larger voids and porosity. The reactivity of a cementitious material increases with fineness until a certain point where extra grinding cannot beneficiate strength development at later ages. Through the optimized particle packing density of composite cement, clinker may become the minor component in the cementitious mix. Addition of mineral and chemical performance enhancer can help to further reduce clinker from composite cements without harming the concrete performances. Looking at the fundamentals by enhancing the reactivity of the different particles allows us to further reduce clinker in cement use. Future approaches might be more technical than only grinding and blending.