Ready-mix concrete producers already running slag, Class C fly ash, or Class F fly ash are under growing pressure — from owners, architects, and general contractors — to lower the Global Warming Potential (GWP) numbers on their Environmental Product Declarations (EPDs). Re-Act 4 SR is engineered precisely for that challenge. Developed as a slag-replacement grade (SR) ground glass pozzolan with a D50 particle size of approximately 6 microns, Re-Act 4 SR integrates into existing batching plant operations with minimal disruption while delivering measurable improvements in durability and embodied carbon.
What Is Re-Act 4 SR?
Re-Act 4 SR is the economical, high-volume variant in the Re-Act 4 product family. Unlike standard Re-Act 4 — which is ground to an ultra-fine level for use in ultra-high-performance concrete (UHPC) and specialized applications — Re-Act 4 SR is optimized to serve as a direct replacement for slag in conventional and high-performance ready-mix production.
Produced from a controlled waste glass stream at a manufacturing center in Waterdown, Ontario, Re-Act 4 SR benefits from supply-chain stability that slag and fly ash cannot match. Slag availability is tied to steel production cycles; fly ash supply depends on coal plant operations. Re-Act 4 SR is manufactured from post-consumer glass — a consistent, abundant feedstock — giving producers reliable access regardless of industrial market swings.
Performance Data: Strength, Permeability, and Durability
Re-Act 4 SR performs comparably to slag across strength gain profiles, making the transition from slag straightforward for mix design engineers. At the recommended replacement range of 20% to 40% by cementitious weight, Re-Act 4 SR achieves:
- Optimal impermeability and compressive strength at 30–35% replacement
- Similar strength controls at 50–55% dosage when blended with cement partners in select applications
- Significantly reduced chloride ion penetration compared to OPC-only mixes
- Improved resistance to sulfate attack and chemical exposure
Life 365 durability modeling has been conducted across multiple dosage rates, confirming long-term structural performance for projects requiring 75- to 100-year service life expectations — the kind of durability now demanded for data centers, marine infrastructure, and municipal projects.
EPD Performance: One of the Best in the Industry
The EPD for Re-Act 4 SR reports total fossil fuel-related CO₂ at approximately 51.8 kilograms of CO₂ per metric ton. This places Re-Act 4 SR among the lowest-carbon supplementary cementitious materials (SCMs) available in North America — substantially below portland cement and competitive with the best-performing slag and fly ash products.
For concrete producers whose customers are beginning to specify GWP targets on EPDs — particularly data center developers, federal projects, and institutional owners — Re-Act 4 SR provides a direct, documentable path to lower embodied carbon without reformulating entire mix designs.
Logistics: Supersacks, Silos, and Bag-to-Bulk
One of the most common questions from ready-mix producers is whether Re-Act 4 SR can work with standard gravity-fed silos — and the answer is yes. The recommended supply method for regional markets is:
- Truckload delivery in supersacks to a local inventory location
- Bag-to-bulk transfer into existing silos at the batching plant
- Standard silo handling — no special equipment modifications required
This logistics model makes Re-Act 4 SR accessible to multi-plant operations spread across a metro area, including both fixed plants and portable plant setups. Pricing is structured to be competitive with slag on a delivered basis, with freight worked into project-specific quotations.
Mix Design Support Included
Switching SCMs carries mix design risk, which is why Tech Silica and the Re-Act 4 product team offer direct mix design assistance — including in-house personnel who can develop and stamp mix designs for specific project applications. Producers don’t need to navigate the transition alone.
Sample material is available in advance of bulk orders, allowing plant QC teams to run internal trial batches and verify performance against existing benchmarks before committing to production volumes.
Is Re-Act 4 SR Right for Your Operation?
Re-Act 4 SR is especially well-suited for ready-mix producers who currently use slag as a primary SCM and are receiving specification requests for lower-GWP concrete. It is also a strong candidate for projects with aggressive durability requirements — data centers, bridge decks, parking structures, and any concrete exposed to chloride or chemical environments.
If you supply concrete to markets where EPDs are becoming a standard deliverable, Re-Act 4 SR gives you a competitive answer backed by third-party EPD documentation, Life 365 modeling, and comparative testing data.
Get the Data
Tech Silica provides a complete technical package including comparative testing sheets, Life 365 modeling reports, and the full EPD for Re-Act 4 SR. Contact us to request a sample or discuss supply logistics for your region.
Learn more about our full Ground Glass Pozzolan product line at technicalco.com/ground-glass-pozzolan.