Abdullahi Ahmed

The escalating global emphasis on sustainable construction and renewable materials has highlighted agricultural waste valorization as a critical research domain, particularly in response to the climate emergency. As the construction industry seeks alternative ecofriendly materials to mitigate environmental impact and expand affordable housing solutions, there is a pressing need to explore and evaluate suitable biomass resources in greater depth. Among these, corncob (CC) emerges as a significantly underutilized material with considerable potential for sustainable applications. Despite its abundance and promising properties, systematic understanding of the composition–structure–function relationships within CC anatomical fractions remains limited, impeding its optimal utilization in building and construction. This study employs a multi-analytical approach to investigate the intricate correlations between CC morphology, mechanical attributes, and chemical composition to establish its viability as a sustainable building material (SBM). The methodology integrated microscopic analysis (SEM–EDS), mechanical characterization, and chemical assays. Microscopy reveals differentiated ultrastructure that collectively confer balanced strength–ductility attributes. Elemental mapping demonstrated predominant carbon (64.73–67.74%) and oxygen (31.22–34.05%) composition, with strategic distributions of silicon (2.52%) and aluminum (0.69%) contributing to mechanical properties. Mechanical testing showed compressive strength (67.6 MPa) attributable to the lignocellulosic reinforcement grid resisting fractures. Comparatively, tensile testing indicates elasticity (Young’s modulus 191.19 MPa), exceeding most agricultural residues resulting from interfibrillar sliding mechanisms accommodating strains. Chemical analysis revealed optimal lignocellulosic composition complemented by functional additives (1% pectin, 4.21% resistant starch). Integrated morphological and mechanical characterization coupled with compositional mapping and the preliminary life cycle assessment substantiate cob waste as an economical bio-based substitute for mainstream building insulation, 3D printing, carbon sequestering, structural, and non-structural applications. The multi-level examination provides understanding of structure–function influences to direct processing interventions for customized material properties. Graphical abstract

The construction sector faces pressure to decarbonise while addressing rising resource demands and agricultural waste. Ordinary Portland cement (OPC) is a major CO₂ emitter, yet biomass residues are often open-burned or landfilled. This study explores corncob ash (CCA) as a sustainable supplementary cementitious material (SCM), examining how calcination conditions influence pozzolanic potential and support circular economy and climate goals, which have not been adequately explored in literature. Ten CCA samples were produced via open-air burning (2–3.5 h) and electric-furnace calcination (400–1000 °C, 2 h), alongside a reference OPC. Mass yield, colour, XRD, XRF, LOI, and LOD were analysed within a process–structure–property–performance–sustainability framework. CCA produced in a 400–700 °C furnace window consistently achieved high amorphous contents (typically ≥80%) and combined pozzolanic oxides (SiO₂ + Al₂O₃ + Fe₂O₃) above the 70% ASTM C618 threshold, with 700 °C for 2 h emerging as an optimal condition. At 1000 °C, extensive crystallisation reduced the expected reactivity despite high total silica. Extended open-air burning (3–3.5 h) yielded chemically acceptable but more variable ashes, with lower amorphous content and higher alkalis than furnace-processed CCA. Simple industrial ecology calculations indicate that valorising a fraction of global CC residues and deploying optimally processed CCA at only 20% OPC replacement could displace 180 million tonnes CC waste and clinker avoidance on the order of 5–6 Mt CO₂ per year, while reducing uncontrolled residue burning and primary raw material extraction. The study provides an experimentally validated calcination window and quality indicators for producing reactive CCA, alongside a clear link from laboratory processing to clinker substitution, circular resource use, and alignment with SDGs 9, 12, and 13. The findings establish a materials science foundation for standardised CCA production protocols and future life cycle and performance evaluations of low-carbon CCA binders.

Decarbonising the construction industry’s substantial ecological footprint demands credible substitutes that preserve structural performance while valorising waste. Although construction and demolition waste (CD&W) has been widely studied, the vast potential of agricultural residues (e.g., corncob, rice husk) and, crucially, their synergy remains underexplored. This study couples a systematic literature review with mathematical modelling to evaluate binary CD&W–agro-waste binders. A modified Andreasen–Andersen packing framework and pozzolanic activity indices inform multi-objective optimisation and Pareto analysis. The optimum identified is a 70:30 CD&W-to-agricultural ratio at 20% total cement replacement, predicted to retain 86.0% of OPC compressive strength versus a 79.4% average for single-waste systems (8.3% non-additive uplift). Life-cycle assessment (cradle-to-gate) shows a 20.3% carbon reduction for the synergistic blend (vs. 19.6% CD&W-only; 19.3% agro-only); when normalised by strength (kg CO₂-eq/MPa·m³), the blend delivers 6.3% better carbon efficiency than OPC (5.63 vs. 6.01), outperforming agro-only (5.79) and CD&W-only (6.61). Global diversion arithmetic indicates feasible redirection of 0.246 Gt y⁻¹ of wastes (5.7% of CD&W and 1.8% of agricultural residues) at 30% market penetration. Mechanistically, synergy arises from particle size complementarity, complementary Ca–Si reactivity generating additional C–S–H, and improved rheology at equivalent flow. Monte Carlo analysis yields a 91.2% probability of ≥40 MPa and 78.3% probability of ≥80% strength retention for the optimum; the 95% interval is 39.5–55.3 MPa. Variance-based sensitivity attributes 38.9% of output variance to the Bolomey constant and 44% to pozzolanic indices; interactions contribute 19.5%, justifying global (not local) uncertainty propagation. While promising, claims are bounded by cradle-to-gate scope and the absence of empirical durability and end-of-life evidence. The results nevertheless outline a tractable pathway to circular, lower-carbon concretes using co-processed waste. The approach directly supports circular economy goals and scalable regional deployment.

Historically, fire incidents in high-rise buildings reveal that Fire and Rescue Services frequently rely on the stay-put tactic (i.e., occupants of high-rise buildings should remain in their apartments) during an inferno. Recent fire occurrences in high-rise buildings reveal that there are two opposing viewpoints on the stay-put tactic. First, the understanding that the stay-put tactic is a beneficial practice used to protect, control, and facilitate smooth evacuation of occupants during fire incidents. Second, the argument that the stay-put tactic is a misjudgement and futile strategy that leads to fatalities, particularly in high-rise buildings. The aim of this study was to provide awareness and understanding of fire and rescue services use of the stay-put tactic in high-rise buildings. We attempted to answer the questions: is the stay-put tactic a misjudgement or magnificent strategy? The study adopted phenomenological research strategies with various focus groups consisting of seasoned firefighters and survivors with first-hand accounts of stay-put instructions in high-rise buildings. The study also scrutinised three case studies of fire incidents in high-rise buildings in two countries. The study revealed that the stay-put tactic is obsolete; with the potential to cause catastrophic misjudgement, mostly during conflagrations in high-rise buildings. There is a need to advance research on the use of artificial intelligence communication systems and infrared image detectors camera to enhance quick and smooth fire evacuation in high-rise buildings.

Building performance improvement through low-energy renovation traditionally involves building performance diagnostics of the existing building, technology evaluation, selection and implementation. Effective building performance diagnostics, post-retrofit assessment and user engagement are essential to deliver performance as well as achieving socio-economic and environmental benefits at every stage of the renovation project life cycle. User’s views are often ignored when renovating a building, causing sub-optimal energy performance, user comfort and wellbeing. This paper seeks to critically evaluate the low-energy renovation process and the role of user and stakeholder engagement in the strategic implementation of low-energy retrofit technologies for performance improvement of higher education buildings. The research focuses on renovation methodology, innovative materials/systems and end-user engagement throughout the renovation project phases (pre-renovation, the renovation process and post renovation). A mixed research method was adopted, which includes building performance modelling, monitoring and user evaluation questionnaires pre and post-renovation. The research is part of European Union (EU)-funded project, targeting 50% reduction in energy consumption using innovative materials and technologies in existing public buildings. The surveys allow comparative analysis of comfort levels and user satisfaction as an indicator of the efficacy of renovation measures. A new renovation process and user engagement framework was developed. The findings suggest that there is a direct relationship between retrofit intervention, improving energy performance of low-carbon buildings and the comfort of occupants. The technologies and strategies also appear to have different impacts on user satisfaction.

Purpose: The Middle Eastern terrain is expected to encounter unprecedented climatic conditions before the turn of the next century (circa. 80 years), emanating from extreme heat waves that exceed the critical threshold of habitable conditions. This threatens to cause a significant challenge that is exacerbated by a gap between the supply and demand of affordable energy. Therefore, the purpose of this study is to investigate the potential of utilising nearly zero-energy buildings (nZEB) to improve the performance of residential buildings in Iraq and the Middle East.Design/methodology/approach: This study uses Iraq as a case-study because of the breadth of climatic conditions experienced across its wide-reaching territory and also because of the recent critical infrastructural challenges following the geo-political crisis. Three virtual buildings were simulated for Baghdad, Mosul and Basra cities to narrow the confines of the region to achieve nZEB under current and future climatic weather scenarios.Findings: The findings showed that in all three cases studies, the buildings located within the three climatic regions in Iraq could achieve both significant annual energy reductions as well as nZEB standards which could range from 41 per cent to 87 per cent for current climatic conditions and 40 per cent to 84 per cent by 2080. An analysis has also been carried out for the three case-study cities which revealed significant operational-cost savings achievable through nZEB buildings.Originality/value: There are currently limited studies that investigate such positive potential for nZEB strategies under the current and predicted future climatic scenarios in the Middle East.