Reflecting on Concrete 2025: High SCM Replacement & the Rise of New Feedstocks... a.k.a Reformix's BAU
- Sep 9, 2025
- 2 min read
Updated: 2 days ago
The Reformix team attended and presented at Concrete 2025, a conference that made one trend unmistakable: The industry is moving decisively toward high supplementary cementitious material (SCM) replacement and alternative binder systems.
The good news? Reformix has already been working in this space for years.
Across multiple sessions, discussion centered on reducing clinker factors through increased use of:
Ground granulated blast furnace slag (GGBFS)
Limestone blends
Fly ash and coal combustion products
Calcined clays
Alkali-activated systems
The shift is no longer theoretical. Replacement levels of 50–70% are increasingly standard in performance-driven systems, and discussions around 80–90% OPC displacement are gaining traction in specific applications.
Calcined Clays & LC3 Momentum
Calcined clay systems featured prominently.
Rotary kiln activation is enabling the development of reactive metakaolin and LC3-type systems (limestone-calcined-clay-cement blends). These systems offer meaningful clinker reduction while maintaining structural performance and durability. For jurisdictions without abundant slag or high-quality fly ash, calcined clays represent a scalable pathway.
The implication is clear:
Future SCM supply will be diversified: geographically and mineralogically.
Beyond Traditional SCMs
Concrete 2025 also highlighted increasing interest in non-traditional feedstocks, including:
Delithiated beta-spodumene residues from lithium processing
High-amorphous industrial slags and fumer materials
Carbon mineralisation technologies integrating CO₂ into cementitious matrices
These developments signal an important evolution:
Industrial by-products are no longer viewed as secondary substitutes. They are becoming engineered inputs.
The Emerging Challenge
As SCM levels increase and feedstock sources diversify, variability becomes central.
Differences in:
Amorphous content
Particle size distribution
Mineralogical impurities
Surface reactivity
directly influence performance.
High-replacement systems demand high-resolution characterisation. Without rigorous feedstock validation, durability modelling and mix optimisation, elevated replacement ratios risk inconsistency.
A Maturing Transition
Concrete 2025 reflected an industry moving from incremental clinker reduction toward structural reformulation. However, scaling these systems will require:
Standardisation pathways
Durability confidence
Robust quality control
Process-aware mix design
Engineering reliable high-SCM systems is.
The work continues, with Reformix at the frontier of these new and emerging materials.
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