Cathodic protection (CP) limits the corrosion of a metal surface by making it the cathode of an electrochemical cell. This can be achieved either by using a more active sacrificial anode to create a driving current, or by using inert anodes and impressing a current onto the cathode surface using an external direct current (DC) source. Impressed current cathodic protection (ICCP) is preferred where widespread protection is required, particularly in reinforced concrete structures. ICCP needs a constant DC power supply that is usually provided through a grid connection or independent generators. This paper presents the currently available CP systems for reinforced concrete, particularly ICCP, and the possibility of using self-sufficient and renewable energy systems. The potential for overcoming the mismatch (due to intermittent current) in energy provision from renewable sources with energy needs for CP (constant current) is discussed by exploring methods of storing energy and examining the level of protection provided by intermittent current. Areas that require further research to optimise the design of such systems are highlighted.

Building construction accounts for a significant proportion of global greenhouse gas emissions, raw material extraction, and waste production. Applying circular economy (CE) principles in the building construction industry would considerably reduce these values. However, uptake by the industry is relatively slow, which is largely attributed to sectoral barriers, including limitations in knowledge and experience. This review paper aims to assess and contribute to diminishing these obstacles by offering a comprehensive review of circular material usage principles and strategies within the construction sector. Opportunities and facilitators of change are also presented, including innovations and emerging technologies in recycling, digitization, robotic systems, novel materials, and processing. Finally, four case studies demonstrate the application of circular theory via a novel block system, recycled aggregate, modular kitchen reuse, and an energy efficiency retrofit. The conclusions show that future efforts should prioritize the development of strong regulatory frameworks, awareness initiatives, and international cooperation. In this regard, the integration of technological advancements, such as AI, robotics, and blockchain, is essential for optimizing waste management efficiency. Furthermore, education on circular practices plays a critical role. Through global collaboration, standardizing circular construction approaches can promote a more sustainable and resilient building construction industry.

The development of a battery using different cement-based electrolytes to provide a low but potentially sustainable source of electricity is described. The current, voltage, and lifespan of batteries produced using different electrolyte additives, copper plate cathodes, and (usually) aluminium plate anodes were compared to identify the optimum design, components, and proportions to increase power output and longevity. Parameters examined include water/cement ratio, anode to cathode surface area ratio, electrode material, electrode spacing, and the effect of sand, aggregate, salts, carbon black, silica fume, and sodium silicate on the electrolyte. The results indicate that the greatest and longest lasting power can be achieved using high proportions of water, carbon black, plasticiser, salts, and silica fume in the electrolyte and using a magnesium anode and copper cathode. This cell produced an open-circuit voltage of 1.55 V, a resistor-loaded peak current over 4 mA, maintaining over 1 mA for 4 days, and a quasi steady current of 0.59 mA with a lifespan of over 21 days.

Innovative and creative solutions are needed to reduce the substantial carbon footprint of the concrete industry using low-carbon materials. Biochar has been recognised as an environmentally efficient material for concrete production. Also, it is required to build interpretable predictive models to advance modelling-based mix design optimisation. This study uses biochar as a cement substitute in concrete and assesses the mechanical strength using lab tests followed by predictive modelling approaches. Two types of biochar derived from olive pits and wood were used in 2.5 and 5 wt.% of cement. Cubes, cylinders, and beams were cast to test biochar concrete’s compressive, tensile, and flexural strength. The test data were used to develop and validate prediction models for the compressive strength (CS) using linear regression and gene expression programming (GEP) techniques. Moreover, SHapley Additive exPlanation (SHAP) analysis was performed to evaluate the influence of parameters on the CS. The results showed that olive pit biochar was more effective in enhancing the concrete strength than wood biochar due to the reduced particle size. The optimal replacement levels for olive pit biochar were 2.5 wt.% for the CS and 5 wt.% for the split tensile and flexural strength. The GEP model effectively captured the non-linear behaviour of biochar concrete and was more accurate than the linear regression model for the CS. The approach adopted in this study can be used to optimise mix design formulations for biochar concrete. These findings highlight the potential of biochar as a sustainable and effective cement substitute, contributing to the development of greener concrete with improved mechanical performance. Integrating biochar into concrete production can significantly lower the industry’s carbon footprint, promoting environmentally responsible construction practices while maintaining structural integrity.