Fire exposure can cause severe degradation in the mechanical and deformation characteristics of reinforced concrete structures, necessitating effective post-fire strengthening strategies. This study presents a controlled experimental investigation comparing the performance of carbon fiber reinforced polymer (CFRP) confinement and steel jacketing techniques for post-fire strengthening of reinforced concrete columns. Identical column specimens were subjected to controlled fire exposure, followed by strengthening using either CFRP wraps or steel jackets, and subsequently tested under axial compression. The experimental program evaluated residual load-bearing capacity, stiffness recovery, deformation capacity, and energy absorption. The results demonstrate that both strengthening techniques significantly improve post-fire performance, albeit through distinct mechanical mechanisms. CFRP confinement primarily enhances deformation capacity and post-peak stability, while steel jacketing provides superior strength and stiffness recovery. Three-dimensional performance domains reveal clear trade-offs between strength, stiffness, and ductility, highlighting that no single technique is universally optimal. The findings emphasize the importance of performance-based selection of post-fire strengthening strategies based on fire severity and structural performance objectives.

The transition of the construction sector from a linear take-make-dispose model to a circular economy is critically dependent on the availability of reliable, comprehensive information about the materials embedded in the built environment. Concrete, as the world's most consumed construction material, presents a particularly acute challenge: its production accounts for a significant share of global carbon emissions, yet the vast quantities of concrete currently in service remain undocumented and therefore invisible to circular recovery markets. Material passports have been proposed as a digital instrument to address this informational void, but existing passport concepts remain static, lack integration with environmental assessment methodologies, and fail to provide the trust guarantees necessary for transactions among independent actors. This study develops and empirically evaluates an integrated material passport framework for circular concrete management that combines a structured, standards-aligned data model with a dynamic lifecycle assessment engine and a permissioned blockchain trust layer. The research applies a design science methodology, progressing through the formalisation of a 58-field passport schema, the construction of a modular lifecycle assessment computational engine that recalculates environmental impacts as lifecycle events are recorded, the configuration and testing of a blockchain architecture employing Raft consensus and off-chain storage, and the application of the integrated framework to four illustrative circularity scenarios derived from real-world European concrete supply chain data. The passport data model was derived through a criterion-based filtering of 137 candidate fields, achieving a Fleiss’ kappa of 0.84 among domain experts and 72 per cent alignment with existing ISO and CEN standards. The dynamic lifecycle assessment engine demonstrated that tracking a concrete element through multiple use cycles reveals a global warming potential of 171.5 kg CO₂-eq per cubic metre under a three-cycle reuse and recycling scenario, compared with the 327.4 kg CO₂-eq that a static environmental product declaration would report for a single linear cycle, capturing a net environmental benefit of up to 265.9 kg CO₂-eq per cubic metre for intact structural reuse. The permissioned blockchain testnet, configured with four validator nodes, achieved a tamper detection rate of 1.00 across ten deliberate off-chain data alteration attempts with a mean verification latency of 2.7 seconds and an annual network energy consumption of 2,803 kWh, representing less than 0.01 per cent of the global warming potential savings enabled by the system. The Monte Carlo-based economic analysis identified a positive net present value of €2,870 to €3,960 per cubic metre for intact reuse scenarios, with viability thresholds of a virgin concrete price above €120 per cubic metre and a discount rate below 5.8 per cent, and demonstrated that a €40 per tonne carbon price extends economic viability to lower-grade recycling pathways. The study confirms that the integration of material passport design, dynamic lifecycle assessment, and blockchain technology into a single operational framework is technically feasible, environmentally meaningful, and conditionally economically viable. The findings provide an evidence-based template for industry practitioners, standardisation bodies, and policymakers seeking to operationalise digital product passports for construction materials and to advance the circular transition of the concrete sector.