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Durability Performance of 3D-printed Ultra-high Strength Concrete Incorporating Corrosion Inhibitor
No full textThis paper reports preliminary results on the durability performance of a 3D-printed ultra-high strength concrete (3DP-UHSC). A nitrite-based compound was added at varying dosages (0%, 2%, and 4% by mass of binder) to the developed 3DP-UHSC as a corrosion inhibitor. The effects of the corrosion inhibitor on the workability of fresh mixes and the mechanical properties (compressive and flexural strengths in various directions) of the 3DP-UHSC mixes were studied. Furthermore, the durability performance of the 3DP-UHSC was assessed by conducting porosity, water absorption, and chloride permeability measurements. Mould-cast specimens were also prepared and tested for comparison purposes. The results indicated that the nitrite-based corrosion inhibitor slightly enhanced the flowability of the 3DP-UHSC. Furthermore, the addition of a nitrite-based corrosion inhibitor increased the total charge passed while reducing the porosity and water absorption of the developed 3DP-UHSC. In the Z-direction, the mechanical and durability performances of 3D-UHSC were close to those of mould-cast UHSC
Steel Fibre Reinforced Self-Compacting Geopolymer Concrete Structural Members
No full textGeopolymer concrete (GPC) is an innovative and sustainable alternative to ordinary Portland cement concrete (OPC) for structures in seismic prone areas owing to tough and ductile performance due to strong bond with steel reinforcement. However, the application of GPC in construction projects is low due to limited understanding of the long-term performance of structural members. The objective of this study is to examine the effects of steel fibres on the flexural properties of self-compacting geopolymer concrete (SCGC) and OPC beams. The study involved investigation of the fresh and mechanical properties of concrete. Structural parameters such as toughness, and ductility index were examined on beams measuring 150x150x400 mm. Inclusion of steel fibres up to 1% showed the greatest improvement on compressive strength with SCGC and OPC recording a 18% and 20% increase respectively compared to the non-fibre mixes. Maximum tensile strength of 3.8 MPa and 3.9 MPa was achieved for 1.5% fibre addition for SCGC and OPC, respectively. The peak flexural loads of 12.3kN and 21.6kN were achieved for 1.5% fibre content in SCGC and OPC, respectively. However, the improvement in the ductility index was more apparent in SCGC than OPC as 1.5% fibre SCGC recorded 13.4 times more ductility than the control mix while for 1.5% fibre OPC it was 1.7 times. These results depict the potential for steel fibre reinforced GPC to replace OPC in earthquake zones as the increased ductility allows structures to absorb and dissipate energy during an earthquake, which is great for seismic performance
Exploring Aerial Additive Manufacturing with Cementitious Materials using Autonomous Drones
No full textAerial additive manufacturing (AAM) represents a novel approach to construction by enabling untethered autonomous unmanned aerial vehicles (UAVs, or drones) to deposit cementitious materials in mid-flight, overcoming geometric and accessibility limitations associated with ground-based additive manufacturing. This study presents research to investigate the structural viability of cementitious mixes tailored for aerial extrusion, focusing on rheological optimisation, mechanical performance, and deposition feasibility. Pseudoplastic behaviour was achieved through the use of hydrocolloids, enabling low viscosity under shear for extrusion while rapidly stiffening post-deposition to maintain layer geometry. Fibre reinforcement and inorganic fullerene tungsten disulphide (IF-WS₂) nanoparticles were incorporated to enhance flexural strength, interlayer cohesion, and impact resistance. Laboratory trials using a miniaturised UAV-mounted extrusion system demonstrated successful deposition of multiple layers with positional accuracy within ±10 mm. Results indicate that carefully balanced mix compositions allow structural layering, yielding compressive strengths above 25 MPa and improved toughness. The study highlights the potential of AAM for applications in confined, elevated, or hard-to-access environments, while emphasising current limitations including UAV payload, flight stability, and extrusion synchronisation. Overall, this work provides proof-of-concept evidence that autonomous aerial deposition of cementitious materials is feasible, opening avenues for future research into multi-agent cooperative building, material optimisation, and automated construction in challenging conditions
Use of a Bulk Resistivity Index to Evaluate the Permeability Performance of Blended Cements and SCMs
No full textMost specifications for supplementary cementitious materials focus on reactivity as related to strength development. However, beyond strength, the other major benefit from use of SCMs, whether added separately or in blended cements, is their impact on changing the pore structure of the cementitious matrix resulting in improved resistance to ingress of aggressive fluids, i.e. lower permeability. ASTM C1876 and similar test methods in other standards for assessing the bulk resistivity of concrete already exist, but in 2025, ASTM subcommittee C09.48 on Performance of Cementitious Mixtures has adopted ASTM C1952, a standard test method for assessing the relative bulk resistivity of mortar cubes containing SCMs to that of a Portland cement or Portland -limestone cement control. It is anticipated that this test method will be adopted in materials specifications as a performance indicator for the relative permeability reduction to be expected from use of SCMs and blended cements. This test method is also a better tool than strength activity tests for determining whether a proposed new material is a reactive pozzolan or just an inert filler. Details of the test method, and test results, including precision data are provided
Characterization of Incinerator Bottom Ash Aggregate (IBAA) from Four Scottish Incinerators
No full textIncinerator Bottom Ash Aggregate (IBAA), produced as a by-product from Energy-from-Waste (EfW) facilities in Scotland, is gaining acceptance as a sustainable alternative for concrete applications. This shift is driven by Scotland’s forthcoming landfill ban, which encourages increased recycling and diversion of waste from landfill. This study presents a detailed characterization of IBAA, sourced from four Scottish incinerators across various particle size fractions. Physical testing showed that the coarse IBAA fractions (12–22 mm) meet BS EN 8500-2 for use in ready-mixed and precast non-structural concrete. Furthermore, Los Angeles abrasion values (36–42%) and flakiness indices (13–18%) lend themselves well to this type of application. Constituent analyses confirmed compliance with limits for unbound aggregates, brick, glass, and other materials, supporting their suitability in concrete. Chemical analyses revealed that acid-soluble sulfate content in coarse fractions remained around 1%, well within acceptable limits, while finer fractions displayed higher sulfate levels. Metal analysis showed aluminium contents below 1%, with total ferrous and non-ferrous metals typically ranging from 1–2%. X-ray diffraction indicated a predominance of non-crystalline (amorphous) material, as well as beneficial crystalline phases such as calcite, quartz and gehlenite, especially in coarser fractions. Overall, the study demonstrates that the four IBAAs, particularly their coarse fractions, are good-quality, sustainable materials suitable for replacing natural aggregate in non-structural concrete. The use of IBAA can contribute to circular economy goals by reducing landfill use and conserving natural resources
An Academia-Community Partnership Aiming to Benefit the Well-Being of Shelter Cats and Promote the Learning Outcomes of College Students
No full textMore than three million cats enter U.S. animal care and control facilities annually. Although many are adopted, others spend a prolonged amount of time at the animal shelter while facing a variety of stressors. The current project explored the possibility of creating an academia–community partnership aiming to establish a college-based foster program that will allow undergraduate students to socialize and train shelter cats as a part of an academic course. It was hypothesized that the program will positively impact the well-being of shelter cats, improve their adoption outcomes, and support students’ learning outcomes. Students enrolled in the Learning course at Saint Francis University trained a total of 12 shelter cats, fostered on campus premises, throughout two academic semesters. The course’s impact for the cats was evaluated using adoption ratios, latency to adoption, and collar-attached FitBark activity trackers. Students’ learning outcomes were assessed via self-evaluation surveys that measured confidence in cat-training skills, understanding of the scientific methodology, and belief in the emotional capabilities of cats. The surveys were delivered to students enrolled in the Learning course (n = 80) and in a comparably challenging Biopsychology (n = 48) course, taught within the same semesters by the same faculty instructor. Findings demonstrated that the cats were adopted immediately at the end of the semester and that they displayed an adequate activity level. In addition, in comparison to participation in the Biopsychology course, participation in the Learning course was found to enhance students’ confidence in acquired skills and elevate their beliefs in the emotional capabilities of cats. The construction, delivery, and implications of the program are discussed
Indiana at a Glance: County Trends, 2025 Edition
No full textIndiana at a Glance: County Trends, 2025 Edition provides an overview of macro socioeconomic and demographic trends based on county-level data in ten-year periods in Indiana, the upper Midwest region, and the nation. Analyzing data primarily from 2013 through 2023, this book presents information that contextualizes the design and implementation of specific policies enacted by elected officials and community leaders, and reveals the impact these initiatives have on the public.
Inspired, in part, by the United States Department of Agriculture’s Rural America at a Glance reports, as well as the author’s more than twenty years of work in the field, this study makes use of gap analysis to glean valuable insights into how specific socioeconomic patterns relate to larger regional or national trends. It also offers a fuller picture of community economic development planning, allowing community stakeholders to better discern unique opportunities and challenges from macro socioeconomic and demographic noise.
Accessible to scholars and nonacademics alike, Indiana at a Glance is meant to assist community leaders and residents who wish to have a firmer grasp of the socioeconomic and demographic landscape of their communities as they attempt to plan, design, implement, and evaluate their policies and initiatives or simply better understand their communities. The content and analysis supplied in this book will be updated every five years to ensure the most current data is available in order to align with the temporal “horizon” under which community economic development practitioners and policymakers frequently operate.https://docs.lib.purdue.edu/purduepress_ebooks/1083/thumbnail.jp
AGRO, DATA AND THE ENVIRONMENT
No full textAgriculture, once seen as a low-status job involving simple tools like cutlasses, has transformed drastically due to technological innovation and data science. Previously viewed as a laborious and low-prestige occupation, especially in many African countries, farming now incorporates advanced technologies and data analytics. Today, youths and professionals proudly identify as agricultural experts, agro-data analysts, and agricultural engineers, reflecting the sector’s evolution into a high-tech, knowledge-driven field.
This research examines how smart technologies and data analytics can advance sustainable waste management and environmental protection in agriculture. As climate change and population growth strain food systems, innovations such as precision farming, remote sensing, smart irrigation, and vertical farming enhance resource efficiency, optimize land use, and reduce environmental degradation. Data-driven approaches further enable predictive management from monitoring waste streams to optimizing inputs, thereby promoting climate-smart agriculture. Overall, this study highlights the pivotal role of digital agriculture in fostering environmental sustainability and shaping a smarter, greener future for food systems, both in Africa and in the world at large
Spatial modeling improves field assessment of integrated SCN management
No full textField spatial heterogeneity often obscures treatment effects in soybean cyst nematode (SCN) management trials. We compared tensor-product penalized spline (TPS) models to a traditional split-plot ANOVA model to evaluate two genetic resistance sources (PI 88788 and Peking) and fluopyram seed treatment against HG Type 1.2.5.7 SCN populations in Ohio. By definition, HG Type 1.2.5.7 reproduces \u3e10% of the level on a susceptible soybean line when tested on Peking and PI 88788 resistance sources. TPS models substantially improved model fit (62.2 AIC units for yield, 27.5 for reproduction factor) and precision (lower standard errors; for example 67 to 55 kg ha⁻¹) by explicitly accounting for spatial variation. Our spatially informed analysis revealed critical distinctions in management strategies: Peking-derived resistance significantly outperformed PI 88788, providing a 251 kg ha⁻¹ yield advantage and 37% reduction in SCN reproduction. In contrast, fluopyram seed treatment increased yield by 113 kg ha⁻¹ but did not suppress nematode reproduction, functioning as a yield protectant rather than an SCN population management tool. While treatment effect estimates were slightly lower than ANOVA for yield responses, the TPS model provided higher control efficacy estimates, reflecting the spatial adjustment. These results demonstrate that effective management of SCN HG Type 1.2.5.7 requires Peking-derived genetics as the foundation, with seed treatments serving supplementary roles in integrated strategies. Careful stewardship of Peking-derived resistance is essential to preserve this critical management tool for growers
DroneSAR: A UAV based synthetic sperture radar for soil moisture remote sensing
No full textSoil Moisture is a critical component of the earth water cycle and very important for plant health and development. DroneSAR is a drone based synthetic aperture radar technology that can provide high resolution field level soil moisture measurement data that can be used for flood/drought monitoring and crop yield prediction. Currently, this technology is under algorithm development for soil moisture retrieval