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Fibrous plaster is a culturally significant material used in high-status buildings from the late nineteenth century. Fibrous plaster ceilings are typically suspended using load-bearing fibrous plaster wads, which are attached to roof structure components. Understanding the behaviour of wads is highly significant, with important safety implications emphasised by the partial collapse of the Apollo Theatre ceiling in 2013. This study demonstrates an original, innovative test method for fibrous plaster wads that enables quantification of load capacities, with manufactured specimens representative of historic in situ wads. The methodology is rigorously evaluated for traditional and alternative wad designs, reinforced with hessian scrim or continuous fibre glass (CFG) mat, with and without steel wires in looped (untwisted) or looped-twisted configurations. Tensile tests generated load-displacement characteristics and determined failure modes including cracking of plaster, deformation and tearing of fibrous reinforcement, and if present, plastic failure of a wire. Results demonstrate that hessian performs better than CFG in axial tension and inclusion of a wire increases tensile load capacity and ductility. An industry standard repair wad with hessian and looped-twisted wire can typically support 3 kN. Looped wire performed better in isolation than looped-twisted wire, with higher peak loads and greater ductility, while looped-twisted wire carried a greater load as part of a fibrous plaster composite wad. The test methodology and findings have revealed new insights into the mechanical behaviour of wads which will inform commercial practice and conservation of historic buildings, preserving important heritage and promoting safe longevity. [ABSTRACT FROM AUTHOR]

Additive manufacturing in construction typically consists of ground-based platforms. Introducing aerial capabilities offers scope to create or repair structures in dangerous or elevated locations. The Aerial Additive Manufacturing (AAM) project has developed a pioneering approach using Unmanned Aerial Vehicles (UAV, 'drones') to deposit material during self-powered, autonomous, untethered flight. This study investigates high and low-density foams autonomously deposited as structural and insulation materials. Drilling resistance, mechanical, thermal and microscopy tests investigate density variation, interfacial integrity and thermal stability. Autonomous deposition is demonstrated using a flying UAV and robotic arm. Results reveal dense material at interfaces and directionally dependent cell expansion during foaming. Cured interfacial regions are vulnerable to loading parallel to interfaces but resistant to perpendicular loading. Mitigation of trajectory printing errors caused by UAV flight disturbance is demonstrated by a stabilising end effector, with trajectory errors =10 mm. AAM provides a significant development towards on-site automation in construction. [ABSTRACT FROM AUTHOR]

Construction projects using emerging bio-based materials have been realized over the past ten to fifteen years within Europe. Bio-based buildings utilize properties of natural materials to regulate internal environments, particularly fluctuations in temperature and relative humidity. Despite individual exemplar projects demonstrating functional performance and long-term operational cost savings, there hasn't been a proliferation of commercial or domestic bio-based projects. With a growing shift towards circular economy construction, bio-based buildings could be readily adopted to meet this development. This study evaluates barriers faced by bio-based materials, making the upscaling of production and a breakthrough into mainstream construction challenging. Evaluation was achieved through senior professionals with experience in bio-based construction participating in semi-structured interviews based on core categories of finance, knowledge, and policy. Challenges include the upscaling of production by manufacturers of emerging materials, inconsistencies in life cycle assessment, material certification and accreditation, vested interests in the construction industry, and concerns regarding initial costs, availability, and knowledge of products. Potential solutions for upscaling bio-based construction are identified and include increased case studies, positive legislation, regional economic regeneration, the wellness agenda, long-term economic sustainability, and engagement with established construction companies. This insight has informed the procurement process, material evaluation, and adoption of policy. [ABSTRACT FROM AUTHOR]