THE APPLICABILITY OF RECYCLED WASTE PAPER AS LIGHTWEIGHT BUILDING MATERIALS.

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.In this era of increasing standard of living and rapid growth of civil engineering construction, environmental issues pertaining to natural resources depletion, global warming, energy crisis, waste pollution and greenhouse gas emission have been major issues of concern throughout the world and most especially in the construction industry. This research was conducted to investigate the applicability of recycled wastepaper as lightweight building materials with focus on contributing to sustainability in the creation of the built environment. The major aim was to develop an eco-friendly lightweight non-loadbearing block from recycled wastepaper without the use of cement as binder. This study specifically addressed the drawback of low strength development that usually occur with increasing wastepaper content in the existing cement-based-wastepaper blocks. It also indirectly addresses; the environmental impacts associated with the construction industry (including; high consumption of natural resources, greenhouse gas emission, high energy consumption and so on), the environmental pollution resulting from unsustainable waste generation, and the generic drawback of high water absorption that plagues wastepaper-based blocks. To achieve this, research methods including; laboratory experimentation and simulation modelling were employed. The research outcome is an eco-friendly block unit designated as Cement-less Wastepaper-based Lightweight Block (CWLB) which contains 75% waste content and exhibiting properties that satisfy the requirements for application as non-loadbearing lightweight blocks in building construction. CWLB displayed compressive strength that far outweighs those recorded for the existing cement-based wastepaper blocks available in the literature. The properties recorded for the optimal CWLB includes; 2.71 MPa average compressive strength, 901.5 kg/m3 average density, 0.19 W/m.k thermal conductivity, 989.9 m/s ultrasonic pulse velocity, 0.0026 g/m2.S0.5 average coefficient of capillary water absorption and 883.38 MPa estimated elastic modulus. The approximate compressive strength of 2.38 MPa and 1.58 MPa were respectively predicted and recorded for the solid and hollow finite element model samples of CWLB. The impressive satisfactory properties of CWLB for the intended application and its eco-friendliness in terms of natural resources conservation and improved compressive strength suggests that CWLB shall indeed serve as a more sustainable alternative to the reigning/existing cement-based-wastepaper blocks and to the conventional masonry blocks of the same category. Amongst other things, future work will address the validation of the approximate compressive strength predicted for the solid and hollow CWLB insitu samples in order to take further the subject matter

Strength and stiffness properties of the optimum mix composition of cement-less wastepaper-based lightweight block (CWLB)

The cement-less wastepaper-based lightweight block (CWLB) is a newly developed eco-friendly non-load bearing block manufactured from majorly cellulosic wastes without the use of cement. The main constituents of CWLB includes; wastepaper aggregate (WPA) produced from post-consumer wastepaper, waste additive and sand. This study was conducted to determine its optimum mix composition and the corresponding strength and stiffness properties. The experimentations carried out covered; the optimization of the mix composition of CWLB using the Taguchi statistical optimization technique (TSOT) and the determination of the compressive strength, density, elastic modulus and the ultrasonic pulse velocity (UPV) of the optimal CWLB specimen. The findings from the TSOT ascertains that the optimum mix composition of CWLB comprises of processing parameters including; 2.5 WPA/sand ratio, 0.75 water/binder ratio, and 3.5 Metric ton (i.e. 13.7 MPa) compacting force. Also, it was found that the optimal CWLB exhibited; an average compressive strength of 2.71 MPa, an average density of 901.5 kg/m3, an average UPV of 989.9 m/s and an estimated elastic modulus of 883.4 MPa. The comparison of these properties with the applicable standard requirements indicates the suitability of CWLB for non-load bearing application. In addition, the presence of 75% waste content in the mix composition of CWLB indicates its eco-friendliness and its potential to contribute to the sustainability in the construction industry through reduction in natural resources consumption. The innovation presented in this study includes; the development of a suitable optimum mix composition of constituent materials for the novel CWLB, the identification of factors that affects it strength properties and the determination of its engineering properties. Future work will investigate other relevant properties of CWLB which include; capillary water absorption, thermal conductivity, and the reaction to fire

Optimization of mix composition of cement-less wastepaper-based lightweight block (CWLB)

The development of cement-less wastepaper-based lightweight block (CWLB) is another important step towards the production of eco-friendly building materials from wastepaper. This block which was designed to be used for non-load bearing/non-structural application was developed without the use of hydraulic cement. This study was conducted to optimize the mix composition of CWLB for the purpose of maximizing its compressive strength. This aim was achieved by employing the Taguchi statistical optimization technique in conjunction with laboratory experimentation. The result indicated that water/binder ratio had the most significant effect on the compressive strength of CWLB. The analysis of result establishes the CWLB specimen with optimal parameter to be that which was made from; 2.5 WPA/Sand ratio, 0.75 Water/binder ratio, and 3.5 Metric ton (i.e. 13.7MPa) compacting force. Also, the optimal CWLB displayed; an average compressive strength of 2.71MPa which indicated an increase of 402% compared to the 0.50MPa displayed by the worst parameter combination and an average density of 901.5kg/m3. The compressive strength and the density of the optimal CWLB was found to maximally satisfy the requirements for non-load bearing lightweight blocks. Considering the high amount (typically, 75%) of waste content in the composition of CWLB, it was reckoned as a viable eco-friendly lightweight block suitable for non-load bearing application. Future work will investigate other relevant properties of CWLB which include; Elastic modulus, water absorption, thermal conductivity, and reaction to fire. Key-Words: - Taguchi method, compressiv

Investigation into the applicability of brewery sludge residue-ash as a base material for geopolymer concrete

The environmental challenges such as high energy demand, large CO2 emission, and exorbitant raw material consumption among others associated with ordinary Portland cement led researchers to the search for alternatives and thus the advent of geopolymer concrete. Fly ash, a waste product of the thermal generating power station, has been the base material commonly used in geopolymer production. However, Nigeria depends majorly on hydro-power and hence, fly ash is unavailable and this has contributed to the restricted application of geopolymer technology. Therefore, the suitability of brewery sludge residue (a waste byproduct generated in high quantity from brewing process) as an alternative base material in geopolymer concrete was investigated in this study. The physical and chemical properties of brewery sludge residue ash (BSA) were investigated to assess its suitability for use as a base material for geopolymer binder. Brewery sludge residue ash-based geopolymer concrete (BSAGC) specimens were produced by activating BSA with selected alkaline liquids (NaOH and Na2SiO2) used as activator. The BSAGC specimens were subjected to compressive strength to assess the strength development and consequently the effectiveness of the polymerization reaction that occurred. It was found that, amongst other factors, the BSA exhibits less satisfactory oxide characteristics at 425 micron particle size utilised and consequently the compressive strength development was low at 28 days curing duration at the 1:2:4 mix proportioning threshold adopted for the BSAGC mix. Given the marginal strength development of BSAGC, BSA could be reckon as having potentials for application as base material for geopolymer binder, however, more investigation is required to determine the optimum processing parameters for its usage as a base material for geopolymer binder and geopolymer concrete

A critical review of developers’ decision criteria for Brownfield regeneration: development of the BRIC index

© 2023 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/su15097105The complexity of processes and constraints associated with redevelopment of brownfield lands calls for provision of relevant, adequate, sufficient, up-to-date, and easily accessible information on brownfield lands to enable developers make an informed decision when navigating the hurdles of brownfield redevelopment. Furthermore, the various obstacles and barriers that developers encounter during decision making for brownfield redevelopment has continued to contribute to the limited uptake of brownfield lands in England by developers for redevelopment and regeneration. This study was conducted to explore the factors that developers consider when redeveloping brownfield lands and to present a decision criterion that will support brownfield site selection and subsequent regeneration. A mixed methodology using qualitative and quantitative approaches was adopted to investigate the factors, criteria, and information that developers consider when making decisions for brownfield redevelopment. Data collection was carried out using a literature review and interviews with brownfield experts. Using a purposeful sampling approach, a total of 11 brownfield stakeholders, which cut across key experts involved in brownfield redevelopment within the Black Country region of England, was interviewed. Each expert interviewed holds a stakeholder critical role in regulatory organisations and construction industry organisations, including local authorities, geo-environmental organisations, land remediators and consultants, housing developers, etc. A comparative analysis of evidence obtained from developer interview responses, the literature review, and the brownfield register showed that 57% of factors, criteria, and information such as cost/capital expenses, funding, contamination level, infrastructure, water risk, neighbours, connectivity (digital, energy networks/grid), and access and transport, which developers require for decision making relating to redevelopment of brownfield sites, are not available on a standard local authority’s brownfield land register. To address the identified information gaps, this study developed “The BRIC Index”, a decision-making tool that incorporates a GIS-based system to facilitate screening of brownfield sites based on specified criteria and to help identify risks, contamination, and remediation costs of brownfield development. The effectiveness of the BRIC Index was validated through successful usage for site selection by various SMEs in the Black Country.The BRIC University of Wolverhampton is part funded by the European Regional Development Fund (ERDF). BRIC project reference is 01R17P01468.Published versio