Pre-cast concrete is more affordable, controllable, quicker-to-install than onsite concrete-casting and aligns with UK Govt ambition to promote off-site manufacturing/modular construction.\[1\] However, today's pre-cast concrete mixes pose numerous challenges: 1\. The production of cement (concrete's binding agent) is highly-carbon-intensive (860kgCO2e/tonne)\[2\]. 2\. The cement content required to reach design strength gives pre-cast concrete a high carbon footprint (256-329kgCO2e/cu.m), despite using cement replacements. 3\. Cement replacements retard curing/strength-development (16-hour-demoulding, 14-day safe-transport), limiting productivity and risking damage during handling/storage. 4\. Steel reinforcement enhances early-age-strength but increases product-cost and embodied-carbon. Nationwide-Engineering-Research-and-Development-Ltd(NERD)'s patented Graphene-Enhanced-Concrete(GEC) admixture, CONCRETENE, has been previously developed for the ready-mixed concrete sector, where the strength-enhancing effect of graphene enables reduced cement-content, or reduced concrete-volumes compared to traditional Ordinary-Portland-Cement(OPC), or replacement-material blends (e.g.CEM-III). These material-savings deliver a significantly reduced carbon-footprint (up to 30% reduction). In addition to decarbonisation, CONCRETENE accelerates strength-development/reduces curing time (e.g. 220-Tonne CONCRETENE slab reached 28-day design strength in just 24-hours in I-UK:99366). CONCRETENE is therefore ideally suited to address the major precast sector challenges, but first needs to be reformulated to meet the more complex-chemistries and production-demands of precast vs ready-mixed. The GRAPHcast project is a collaboration between CONCRETENE developers, NERD, and Roger-Bullivant-Ltd(RBL), part of the international Vinci-Group that incorporates Soletanche-Bachy, world-leader in building-foundations, with operations in 60 countries. Alongside iterative CONCRETENE reformulation by NERD, testing, scale-up, and site-trials by RBL will assess performance in precast piles and beams for residential-buildings and low-rise structures. Finally, by validating performance on a live-construction site, GRAPHcast will pave the way for rapid commercialisation of CONCRETENE. Although precast is a smaller market than ready-mixed concrete (and therefore less attractive to private-investors), it is easier to exploit in the short-term, since sales can leverage the well-established sales-network of RBL, in contrast to relying on NERD making direct-sales to individual companies. \[1\]Construction-Playbook:https://www.gov.uk/government/publications/the-construction-playbook \[2\] ICE: https://www.ice.org.uk/media/200i0yqd/2022-04-26-low-carbon-concrete-routemap-final\_rev.pdf

Conventional Portland cement (PC) production is a major contributor to global CO2 emissions and hence there is a great deal of commercial interest in low carbon cements. One variety of such low carbon cements can be produced by mixing binder materials (including heat treated clays, industrial ashes or slags) with an alkaline chemical activator and construction aggregates to form concrete. The mixture sets and hardens but the new cements have associated CO2 emissions that are much lower than those associated with PC manufacture. These cements (which are the subject of this project), now need to be optimised, manufactured and their performance demonstrated as fit for purpose on a commercial scale. The project includes a supply chain focused consortium including manufacturers of chemical activators, precast and ready-mixed concretes. The project is conducting industrial plant trials, generating performance and durability data, optimising the chemical activator compositions and addressing barriers to market.