Mining the physical infrastructure: Opportunities, barriers and interventions in promoting structural components reuse

Construction is the most resource intensive sector in the world. It consumes more than half of the total global resources; it is responsible for more than a third of the total global energy use and associated emissions; and generates the greatest and most voluminous waste stream globally. Reuse is considered to be a material and carbon saving practice highly recommended in the construction sector as it can address both waste and carbon emission regulatory targets. This practice offers the possibility to conserve resources through the reclamation of structural components and the carbon embedded in them, as well as opportunities for the development of new business models and the creation of environmental, economic, technical and social value. This paper focuses on the identification and analysis of existing interventions that can promote the reuse of construction components, and outlines the barriers and opportunities arising from this practice as depicted from the global literature. The main conclusions that derive from this study are that the combination of incentives that promote recycling and reuse with the provision of specialised education, skills and training would transform the way construction sector currently operates and create opportunities for new business development. Moreover, a typology system developed based on the properties and lifetime of construction components, is required in order to provide transparency and guidance in the way construction components are used and reused, to make them readily available to designers and contractors. Smart technologies carry the potential to aid the development and uptake of this system by enabling efficient tracking, storage and archiving, while providing information relevant to the environmental and economic savings that can be regained, enabling also better decision-making during construction and deconstruction works. However, further research is required in order to investigate the opportunities and constraints of the use of these technologies

Smart technologies: Enablers of construction components reuse?

Purpose: The exploitation of smart technologies such as, Radio Frequency Identification (RFID) and Building Information Modelling (BIM) for tracking and archiving the properties of structural components, is an innovative disruption in the construction sector. It could stimulate reuse of construction components, rather than their wastage addressing a serious pressing problem. Methods: This study explores the potential of smart technologies to facilitate construction components reuse, and develops a guidance list for promoting their redistribution back to the supply chain. A preliminary assessment of the strengths, weaknesses, opportunities and threats of the RFID technology is presented in order to depict its current and future potential in promoting construction components’ sustainable lifecycle management, and in capturing and creating value. Results: For both RFID and BIM technologies to operate successfully, the right amount and flow of information at each stage of the design-construction-deconstruction-reuse-disposal process is a prerequisite. Although a number of limitations related to the technical operability and recycling of RFID tags currently withhold its roll-out, technological innovation may provide solutions for the future, enabling it to become mainstream. Conclusions: the use of RFID in the construction sector can create the right conditions for the development of new business models based on the reuse and lifecycle management of components, unlocking multiple technical, environmental, economic, and social benefits. With technological innovation enhancing the capabilities of RFID, and with policy interventions controlling and managing its uptake at all stages of the supply chain, its use as a construction components reuse enabler might soon become realised

3D printing of cement composites

The aims of this study were to investigate the feasibility of generating 3D structures directly in rapid-hardening Portland cement (RHPC) using 3D Printing (3DP) technology. 3DP is a Additive Layer Manufacturing (ALM) process that generates parts directly from CAD in a layer-wise manner. 3D structures were successfully printed using a polyvinylalcohol: RHPC ratio of 3:97 w/w, with print resolutions of better than 1mm. The test components demonstrated the manufacture of features, including off-axis holes, overhangs / undercuts etc that would not be manufacturable using simple mould tools. Samples hardened by 1 day post-build immersion in water at RT offered Modulus of Rupture (MOR) values of up to 0.8±0.1MPa, and, after 26 days immersion in water at RT, offered MOR values of 2.2±0.2MPa, similar to bassanite-based materials more typically used in 3DP (1-3 MPa). Post-curing by water immersion restructured the structure, removing the layering typical of ALM processes, and infilling porosity

Highlighting the need to embed circular economy in low carbon infrastructure decommissioning: The case of offshore wind

Development and deployment of low carbon infrastructure (LCI) is essential in a period of accelerated climate change. The deployment of LCI is, however, not taking place with any obvious long term or joined up thinking in respect of life-cycle material extraction, usage and recovery across technologies or otherwise. This proposition is demonstrated through empirical quantification of selected infrastructure and a review of decommissioning plans, as exemplified by offshore wind in the United Kingdom. There is wide acknowledgement that offshore wind and other LCI are dependant on the production and use of many composite and critical materials that can and regularly do inflict high impacts on the environment and society during their extraction and manufacturing. To optimise resource use from a whole system perspective, it is thus essential that the components of LCI and the materials they share and are comprised of, are designed with a circular economy in mind. As such, LCI must be designed for durability, reuse and remanufacturing, rather than committing them to sub-optimal waste management and energy recovery pathways. Beyond a promise to remove installed components, end-of-life decommissioning plans do not however provide any insight into a given operators’ awareness of the nuances of their proposed material management methods or indeed current or future management capacities. Decommissioning plans for offshore wind are at best formulaic and at worst perfunctory and provide no value to the growing movement toward a circular economy. At this time, millions of tonnes of composites, precious and rare earth materials are being extracted, processed and deployed in infrastructure with nothing in place that suggests that these materials can be sustainably recovered, managed and returned to productive use at the potential scales required to meet accelerating LCI deployment. Academic and industry literature, or lack thereof, suggest that this statement is largely reflected throughout LCI deployment and not just within the deployment of offshore wind in the UK

RNAi-mediated abrogation of trehalase expression does not affect trehalase activity in sugarcane

To engineer trehalose metabolism in sugarcane (Saccharum spp. hybrids) two transgenes were introduced to the genome: trehalose-6-phosphate synthase- phosphatase (TPSP), to increase trehalose biosynthesis and an RNAi transgene specific for trehalase, to abrogate trehalose catabolism. In RNAi-expressing lines trehalase expression was abrogated in many plants however no decrease in trehalase activity was observed. In TPSP lines trehalase activity was significantly higher. No events of co-integration of TPSP and RNAi transgenes were observed. We suggest trehalase activity is essential to mitigate embryonic lethal effects of trehalose metabolism and discuss the implications for engineering trehalose metabolism