Āmiomio Aotearoa

Permanent URI for this collection

Āmiomio Aotearoa is a transdisciplinary, multi-partner research project funded by the Ministry for Business, Innovation and Employment (MBIE) and hosted by the University of Waikato.

Recent Submissions

Now showing 1 - 4 of 4
  • Item
    Assessment of the Potential of Waste Copper Chromium and Arsenic (CCA)-Treated Timber Fibre Reinforced Polypropylene Composites for Construction
    (Journal Article, MDPI AG, 2023) Nelson, Jacob; Pickering, Kim L.; Beg, Mohammad Dalour Hossen
    This paper investigates the potential of recycling waste copper chromium and arsenic (CCA)-treated timber for use as a reinforcement material in wood–plastic composites (WPCs) produced for use in construction, including an assessment of mechanical properties and the leaching of heavy metals. Wood flour was obtained through mechanical grinding, and fibres were obtained through alkaline digestion followed by bleaching. Composites produced with 40 wt.% bleached fibres showed increased tensile strength from 18.5 MPa for the polypropylene used as the matrix to 27.6 MPa. Likewise, the Young’s modulus was increased from 0.84 to 2.33 GPa. The treatment of fibres was found to reduce arsenic concentration by up to 99.9%. Furthermore, the arsenic in the leachate from composites was found to decrease from 41.29 to 0.07 ppb when comparing CCA-treated wood flour composites to bleached fibre composites. The composites’ material properties indicate that the use of end-of-life CCA-treated timber could be used to produce a composite material that could be used in New Zealand’s building sector to meet the requirements of semi-structural applications.
  • Item
    The effects of alkaline digestion, bleaching and ultrasonication treatment of fibre on 3D printed harakeke fibre reinforced polylactic acid composites
    (Journal Article, Elsevier BV, 2023-03) Beg, Mohammad Dalour Hossen; Pickering, Kim L.; Gauss, Christian
    This paper documents an investigation of the effects of fibre treatment on New Zealand flax (harakeke) fibre reinforced polylactic acid (PLA) composites. The raw fibre was alkali digested, followed by bleaching and then modified with ultrasonication. Alkali treatment removed lignin and other non-cellulosic components and partially separated fibre bundles while bleaching further removed lignin and improved the separation of elementary fibres, resulting in microfibres with a cellulose content 92 wt%. With subsequent ultrasonication, microfibrils could be seen partially separated (defibrillation) at fibre surfaces. Treated fibres were compounded with PLA at a fibre loading of 30 wt% and extruded into composite filaments. Filaments from alkali, bleached and ultrasonication-treated fibres had smooth surfaces, which translated into high-quality printability along with good mechanical performance. The combination of chemically treated microfibres with selective surface defibrillation using ultrasonication and fibre alignment induced by the printing process resulted in 3D printed samples with a tensile strength of 79 MPa and Young’s modulus of 8.7 GPa, which are the highest values reported so far for 3D printed PLA-based composites reinforced with short fibres.
  • Item
    Construction and demolition Material Flow Analysis Data Base
    (University of Waikato, 2020) Nelson, Jacob Martin Bruton; Elliot, Grace; Pickering, Kim L.
    The following document provides all of the data and estimates provided in the Material Flow Analysis Report. The focus of the report and database were to assess and estimate material flow at four key stages of construction and demolition in NZ. The data displayed in this database is focused on the material flow in residential construction and demolition.
  • Item
    Preliminary materials flow analysis for Aotearoa New Zealand’s building construction sector
    (Report, University of Waikato, 2022) Nelson, Jacob Martin Bruton; Elliot, Grace; Pickering, Kim L.; Beg, Mohammad Dalour Hossen
    This report describes the methodology used to produce a database of construction material flow in Aotearoa New Zealand and summarises the contents of that database. The database was produced as part of a wider research programme, Āmiomio Aotearoa, which aims to help New Zealand transition to a circular economy. In order to assess the materials flowing through the building construction sector, the research focussed on residential dwellings, which constituted a larger proportion of the sector than commercial construction in terms of number of new buildings, floor area of new buildings, and the value of new buildings.¹ The building envelope, including the foundations, structure, cladding, roofing, insulation, and lining of the structure, was examined as it accounted for the largest portion of materials in each dwelling. The data was assessed through the four key stages of material flow: material input, construction, demolition and material output. In terms of material input, timber was the most thoroughly documented material used in construction. An estimated 1.98 million tonnes of timber and timber-based products were supplied to the New Zealand market through local production and imports in 2021. Furthermore, it was estimated that roughly 10.4 million tonnes of ready-mix concrete were used in 2021. Meanwhile, approximately 850 thousand tonnes of steel are consumed within New Zealand annually. However, the amount of concrete and steel that is consumed in the building construction sector specifically is unknown. An estimation of the materials used in the envelope of residential buildings, based on consent data, New Zealand building reports and standard residential building designs, suggested that concrete and masonry were the most used materials in construction, followed by timber, plasterboard, and metals. In total, it was estimated that 2.07 million tonnes of material were consumed in 2021 in the residential construction sector. A case study using purchase order data validated this estimation, showing that the key materials studied were all of the same magnitude. Data on the number of demolitions in New Zealand was very limited, largely because consents are not required for the demolition of houses under three stories.² However, using some assumptions around census and new building consent data, it was calculated that roughly 5,488 residential demolitions occur annually in the current state of the industry. Waste from the building construction sector was studied in terms of the whole construction and demolition sector, as well as the expected waste from residential construction and demolition. It was expected that the total construction and demolition sector produces roughly 3.6 million tonnes of waste annually, with an additional 1.4 million tonnes of material from construction being recovered. However, the study found that the differentiation between infrastructure, commercial, and residential construction waste was largely unmeasured. The residential construction sector was estimated to produce 347 thousand tonnes of waste in 2021, of which 267 thousand tonnes was expected to go to landfill. This waste was produced from: The building envelope (147 thousand tonnes); the rest of the construction (49 thousand tonnes); alterations of residential buildings (25 thousand tonnes); and demolition of residential structures (126 thousand tonnes). Estimations indicated that concrete was the largest contributor to waste, followed by plasterboard and then timber. The report also includes comments from industry experts to further portray the picture of the current state of material flow in the construction and demolition sector, and the issues faced with the production of waste. Overall, this report is a first attempt to provide a picture of materials flowing through New Zealand’s building construction sector. Due to limitations of data currently being collected within NZ and available to the team within the timeframe of the project, the report has focused on estimating the materials used in the shell of residential buildings; detailing where and how materials are being recycled was out of scope. Contradiction with perceived state of the art recycling is likely due, at least in part, to assumptions that because materials can be recycled, they are indeed being recycled (as per our domestic recycle bins). Despite the data limitations, this report and associated database usefully indicate prime waste materials for incorporation into novel building materials and therefore provide insight to support the direction of future research. The report and associated database also provide a foundation which could be used to support further enterprise to provide a clearer picture of materials flows within the building construction sector.