Graphene-based nano-functional materials for surface modification of wheat straw to enhance the performance of bio-based polylactic acid composites

Data availability: Data will be made available on request.Copyright © 2022 The Author(s). To enhance wheat straw compatibility with the polylactic acid (PLA) matrix, several graphene-based materials (GBMs) derivatives, including graphene nanoplatelets, graphene oxide, and nano graphite particles with a constant fraction of 0.1 wt.-%, were employed for the surface functionalisation of wheat straw. Wheat straw surface quality was assessed by comparing PLA bio-based composites' mechanical and thermal performance with and without GBM surface functionalisation. All the resulting composites with surface functionalised straw particles exhibited higher thermal stability, flexural strength, tensile strength, and tensile toughness than those with pristine straw. This could be associated with the improved straw/PLA matrix interfacial bonding induced by the existence of GBMs on the surface of straw particles which was confirmed through morphology assessments. The mechanical properties investigations revealed maximum enhancements of 27%, 66%, and 322% for flexural strength, tensile strength, and tensile toughness, respectively, for bio-based composites consisting of graphene oxide-functionalised straw particles compared to control samples.This work was funded as part of the HP-CSB project, which has received funding from the Engineering and Physical Sciences Research Council with the following reference: EP/S026487/1. The authors acknowledge Nanesa S. r.l for graphene material supply

Sustainable Valorisation of Silane-Treated Waste Glass Powder in Concrete Pavement

Copyright: © 2021 by the authors. This research presents new insights into the utilisation of waste glass powder in concrete pavements. Two different types of glass powder were used as a partial replacement for sand: 10% neat glass powder (untreated) and 10% silane-treated glass powder. The interfacial bonding properties, physical properties, and mechanical properties of concrete pavement were assessed at 7 and 28 days. Results exposed a reduction of 5% and 2% in the compressive and flexural strengths, respectively, and an increase of 15% in water absorption after the addition of neat glass powder to concrete after 7 days of curing. This is due to weak interfacial bonding between the glass powder and cementitious matrix. However, the incorporation of silane-coated glass powder led to an increase in the compressive and flexural strengths by more than 22% and 28%, respectively, and reduced the water absorption of concrete by 8%, due to the coupling functionality of silane. After 28 days of curing, the compressive strength of concrete increased by 15% and 22% after the addition of neat glass powder and silane-treated glass powder, respectively. In addition, water absorption dropped by 5% and 7% after the incorporation of neat glass powder and silane-treated glass powder

Additive Manufacturing and the Construction Industry

Copyright © 2023 The Author(s). Additive manufacturing (AM), including 3D printing, has the potential to transform the construction industry. AM allows the construction industry to use complex and innovative geometries to build an object, building block, wall, or frame from a computer model. As such, it has potential opportunities for the construction industry and specific applications in the deep renovation process. While AM can provide significant benefits in the deep renovation process, it is not without its own environmental footprint and barriers. In this chapter, AM is defined, and the main materials used within the construction industry are outlined. This chapter also explores the benefits and challenges of implementing AM within the construction industry before concluding with a discussion of the future areas of development for AM in construction.Brunel University London BRIEF award: Additive Manufacturing Technology in Construction (AMTC); 10.3030/101029471 European Union’s Horizon 2020 Research and Innovation Programme (H2020-EU) under grant: Digital fabrication and integration of Material reuse for environmentally friendly cementitious composite building blocks; European Union’s Horizon 2020 Research and Innovation Programme through the RINNO project (https://rinno-h2020.eu/) under Grant Agreement 892071, and the Irish Institute of Digital Business

Optimum mix design for internally integrated concrete with crystallising protective material

In this research, a silica-based crystallizing protective material was integrated into a fresh concrete mix to evaluate its efficacy in reducing water absorption while preserving the compressive strength level of the mixture. An optimum concrete mix design was determined, by producing several concrete mixes with different water-to-cement ratios (w/c) of 0.32, 0.37, 0.40, and 0.46, and treated with 2% and 4% of the crystallizing admixture. Water absorption and the mechanical properties of the treated and control mixes were measured, using the initial surface absorption test (ISAT) and the compressive strength and the flexural strength tests, respectively. Results showed that it is possible to obtain a water-resistant concrete without compromising its compressive strength if the right w/c ratio was used and the proper dosage of the crystallizing material was added. In addition, results revealed that treatment is beneficial only in the case of producing concrete with low w/c ratios of 0.32 and 0.37 and treated with crystallizing material. The compressive strength can increase up to 42% and with a significant drop in water absorption reaches 65%. Treated concrete was analyzed thoroughly under the scanning electron microscope (SEM) and X-ray diffraction (XRD) instrument to show the development of crystals with time and their interaction with the concrete mix

Understanding the challenges of construction demolition waste management towards circular construction: Kuwait Stakeholder’s perspective

Data Availability: Data will be made available on request.Copyright © The Authors 2023 . The built environment sector is under increasing pressure to reduce costs while improving environmental quality. This paper examines Kuwait’s current construction and demolition waste (CDW) management policy, highlights the obstacles faced by recycling processes and suggests solutions to enhance waste management practices. Kuwait has only one landfill dedicated exclusively to CDW, operating since 2009. Even though Kuwait has facilities dedicated to handling and recycling CDW, recycling faces several obstacles that hinder its efficacy. This study aims to identify the impediments to efficient management practices through an extensive review of the literature followed by a questionnaire that was sent to 42 relevant stakeholders and interviews conducted with five stakeholders from the 1) Municipality of Kuwait, 2) the Ministry of Public Works, 3) the Environmental Public Authority, 4) the Kuwait Institute for Scientific Research, and 5) the Environment Preservation Industrial Company. This study concluded that present waste management procedures are inappropriate for achieving the circular construction concept and the 4 R framework (reduce, reuse, recycle and recover). Furthermore, it was found that raising the awareness of construction stakeholders and the public about waste management and recycling benefits is essential. This can be successfully implemented by emphasising recyclable products' economic and financial benefits. There is also a need to enforce Kuwait’s existing environmental legislation and regulations to achieve a better CDW control framework. The outcomes of this study will assist decision-makers in establishing strategies to address the barriers to circular waste management practices in Kuwait and beyond

A review of 3D printing low-carbon concrete with one-part geopolymer: Engineering, environmental and economic feasibility

Data Availability: Data will be made available on request.Copyright The Author(s) © 2022. 3D printing is a developing technology that has the ability to use different materials to produce concrete elements with complex shapes. The utilization of geopolymers or alkali-activated materials (AAMs) in 3D printing is receiving significant interest due to the environmental benefits of replacing ordinary Portland cement (OPC). The use of solid activators to produce a one-part geopolymer can help the broader use of geopolymers at large scales, as the corrosive, viscous, and hazardous liquid activators used in two-part geopolymers do not present a feasible large-scale solution for this technology. This paper reviews the 3D printable one-part geopolymers, their compositions, and the effect of different precursor compositions, activator content, and different admixtures on the fresh and hardened properties of the mixtures. The environmental impact and cost assessment of one-part geopolymers produced by conventional and 3D printing methods are also discussed and compared to OPC and two-part geopolymers. This review concluded that one-part geopolymers are easier to mix and use than two-part geopolymers and have a lower carbon footprint than two-part geopolymers and OPC concrete. However, one-part geopolymers may not be as strong as two-part geopolymers, but they are still better than OPC.Part of the DigiMat project, which has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement ID: 101029471

Wheat straw pre-treatments using eco-friendly strategies for enhancing the tensile properties of bio-based polylactic acid composites

Engineering and Physical Sciences Research Council HPCSB project: EP/S026487/1

Upcycling end-of-life bricks in high-performance one-part alkali-activated materials

One-part alkali-activated materials (AAMs) can preserve natural resources and lower embodied carbon of the built environment by accommodating various wastes, industrial by-products, and end-of-life materials in their composition. This study investigates the feasibility of using end-of-life bricks in two physical states, powder and aggregate, to partially replace fly ash precursor and natural aggregate in AAMs, respectively. The mechanical characteristics, microstructure, water absorption, freeze-thaw and fire resistance of the modified AAMs were evaluated. The effect of adding different ratios of nano graphite platelets was also investigated. Results showed that brick-based one-part AAMs can achieve mechanical properties, pore structure, water absorption and freeze-thaw resistance comparable to fly ash-based AAM while having 65% better fire resistivity. Incorporating bricks as aggregate resulted in a maximum improvement of 17% and 27% in the AAMs' compressive and flexural strength levels, respectively, and a general enhancement in the freeze-thaw resistance with showing no reduction in compressive strength after exposure to elevated temperature. Incorporating 0.1 wt% nano-graphite further enhanced flexural strength by 30%, decreased water absorption by 18% and improved freeze-thaw resistance compared to the mix without nano-graphite. Moreover, adding up to 0.5% nano-graphite enhanced the fire resistivity of the composite, allowing it to exhibit 19% better strength performance than before exposure

Effective extrusion-based 3D printing system design for cementitious-based materials

Mycobacterium tuberculosis (M.tb) infection results in approximately 1.3 million human deaths each year. M.tb resides primarily inside macrophages, and maintains persistent infection. In response to infection and inflammation, platelet activating factor C-16 (PAF C16), a phospholipid compound, is released by various cells including neutophils and monocytes. We have recently shown that PAF C-16 can directly inhibit the growth of two representative non-pathogenic mycobacteria, Mycobacterium bovis BCG and Mycobacterium smegmatis (M. smegmatis), by damaging the bacterial cell membrane. Here, we have examined the effect of PAF C-16 on M. smegmatis residing within macrophages, and identified mechanisms involved in their growth inhibitory function. Our results demonstrated that exogenous PAF C-16 inhibited the growth of M. smegmatis inside phagocytic cells of monocytic cell line, THP1; this effect was partially blocked by PAF receptor antagonists, suggesting the involvement of PAF receptor-mediated signalling pathways. Arachidonic acid, a downstream metabolite of PAF C-16 signalling pathway, directly inhibited the growth of M. smegmatis in vitro. Moreover, the inhibition of phospholipase C and phospholipase A2 activities, involved in PAF C-16 signalling pathway, increased survival of intracellular M. smegmatis. Interestingly, we also observed that inhibition of inducible nitric oxide synthase (iNOS) enzyme and antibody-mediated neutralization of TNF-α partially mitigated the intracellular growth inhibitory effect of PAF C-16. Use of a number of PAF C-16 structural analogues, including Lyso-PAF, 2-O-methyl PAF, PAF C-18 and Hexanolamino PAF, revealed that the presence of acetyl group (CH3CO) at sn-2 position of the glycerol backbone of PAF is important for the intracellular growth inhibition activity against M. smegmatis. Taken together, these results suggest that exogenous PAF C-16 treatment inhibits intracellular M. smegmatis growth, at least partially, in a nitric oxide and TNF-α dependent manner