The impact of food miles on global warming is well documented and there is an increasing movement to reduce the distance that food must travel from the point of production to reaching the consumer.The concept for a fly ash concrete printed bench extends this approach to industrial design through the on-site manufacture of one of the heaviest and bulkiest mainstream products.
This highly sustainable street furniture product concept exploits the emerging technology of 3D concrete printing. By mounting the printing process on a flatbed truck, these notoriously heavy products will be manufactured on-site and on-demand; removing the need for resource intensive production facilities, warehousing and shipping. Moreover, 50% of the concrete build material is fly ash waste that typically ends up as landfill or is released into the atmosphere as a by-product from coal-fired electric generating plants.
There have been numerous blue sky concepts for 3D concrete printing but these have all been based on theoretical approaches that are more akin to polymer-based 3D printing processes than concrete based. This process has its own distinctive challenges that must be considered and resolved if there is to be any viability to product concepts.
The fly ash bench concept is unique in that it has been designed in collaboration with a team of civil engineers who are employed by the same organization as the designer and have prototyped a fully functional 3D concrete printing machine. This has resulted in a bench design that is not overly ambitious but, unlike other concepts for 3D concrete printing, is grounded in viability. The key challenge in translating the concept into commercial reality would be the production of a supporting structure for the prototype 3D concrete printing machine for mounting on a flat bed tuck and its attachment to a standard boom crane for raising/lowering onto the build site. The fly ash concrete bench is an elegant design solution that meets the continuing need for robust outdoor seating. It embodies the message that the industrial design profession is ideally positioned to challenge convention and make a major contribution in reducing the environmental impact of manufactured artifacts.
Dr Mark Evans I/IDSA
Context & Problem
Since the launch of Herman Miller's Aeron chair as a leading example of mainstream sustainable design, the uptake of such methods has significantly increased. However, the challenge of significantly reducing the use of petrochemical-based polymers remains and the issue of 'product miles' remains unresolved. The fly ash 3D concrete printed bench is a unique and novel way to approach the need for sustainable outdoor seating as it integrates a production process that becoming increasingly viable with a product that is needed and desirable. It also serves as an example of how industrial designers can engage with the developers of disruptive technologies to further the contribution of the profession in a move towards more fully integrated approaches to sustainable design.
The aim of the project was to meet the on-going need for desirable and robust street furniture seating for use in civic, corporate and educational spaces. This aim also embodied a substantial challenge in that the design approach required a positive impact on the environment by reducing 'product miles' and employing waste material that would typically become landfill or particulate pollution in the atmosphere. The concept was launched on YouTube in January 2015.
There are particular challenges associated with 3D concrete printing that are not faced by designers who employ the established additive manufacturing processes. The first of these relates to the fact that, unlike conventional 3D printing, there is no support structure so overhangs must not be overly steep to prevent the semi-hardened concrete structure from collapsing. The concept bench design resolves this problem through the use of gentle compound curvature on the ends that maximizes the potential for undercuts but these receive additional structural support from the more vertical sides. The second challenge is to create a form that can be easily smoothed with a 'float' as, in common with other 3D printing processes, a stepped structure remains after the build. The flowing curvature has therefore been designed to facilitate this post production finishing. Whilst the bench is at this stage still a concept design, it is very much grounded in the underlying technology of 3D concrete printing through collaboration with colleagues who had developed the technology and are employed by the same organization.
On a practical level, users are those who seek to rest and socialize in the outdoor environment. The solution provides a comfortable and elegant way to deliver this functionality and make a positive visual contribution to the built environment in which it is located. There is, however, a broader humanistic benefit in that the product will make a positive contribution to the broader environment by employing an approach that minimizes the negative impact associated with its manufacture and makes a positive contribution to the sustainable disposal of waste from power plants. The market for the product is civic, corporate and educational outdoor locations that require seating solutions. The inherent flexibility in the manufacturing process means that it would be possible for there to be a degree of customization in terms of product length although this would require a corresponding change to the wooden top.
Lifecycle considerations are central to both manufacture and end of life reuse. The base is manufacture from 50% fly ash concrete which, in addition to being a by-product, adds to the concrete's final strength and increase its chemical resistance and durability. The top is manufactured from locally sourced hardwood to maintain the approach to minimize product miles. These materials would therefore vary according to location but help contextualize its presence in the natural environment. Having maximized opportunities to reduce the environmental impact through the on-site manufacture of both the bench and use of fly ash; at the end of life the concrete base would be crushed and used as a sub-base in new construction projects. The wooden top has options to be planed clean and reused or converted into chipboard/fibre board products or landscaping chips. Manufacture The base is manufactured as a single part by on-site 3D concrete printing with hand-finished floating to remove stepping. The top and its panelled inserts are manufactured by CNC machining. These are then glued, sanded and sealed with water-thinnable solvent-free oil.