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Challenges and Opportunities in Concrete Precast Sector and its Transition to a Net-zero Future
No full textThis article explores key factors shaping the transition of the precast concrete sector toward net-zero carbon. While not exhaustive, it highlights areas of scientific and technical interest for a specialist audience. The discussion is structured around priority themes: beginning with cement and clinker replacement, followed by production efficiency improvements, rethinking steel usage, carbon sequestration strategies, and, finally, structural optimisation or volume reduction. These areas are often interdependent: for instance, clinker replacement, production efficiency, and structural optimisation are all influenced by the 16 – 18 hour production cycle typical of precast manufacturing. Unlike the readymix sector, precast operates on a fast-paced, low-cost, high-volume model where rapid turnaround is essential to controlling overheads. The sector predominantly uses CEM II/A-L (or LL), incorporating limestone powder, although some manufacturers still rely on CEM I. For structural elements, CEM III/A with up to 50% GGBS is also employed. However, due to the comparable cost of GGBS and CEM I, GGBS is often reserved (correctly) for applications requiring enhanced durability. A major barrier to reducing carbon emissions in precast is the need for early strength gain, which limits the adoption of lower-clinker cements such as calcined clay blends. Addressing this challenge is critical to enabling broader use of low-carbon binders. This article also highlights the contributions of the materials research team at Queen’s University Belfast in supporting the precast industry in Northern Ireland on its path to net-zero
Use Fibre Optic Sensor Systems for Structural Integrity Monitoring in Ageing Sewer Concrete Structures and Pipelines
No full textFibre Bragg Gratings (FBGs) form the basis of a valuable class of sensors that have a number of applications in industry and are formed as a periodic variation in the refractive index of an optical fibre that reflects light at a specific wavelength depending on the strain applied to the fibre – this effect can be related to and then calibrated against the parameter to be measured. A number of different types of sensors have been developed for monitoring sewer structures, detecting strain and potential leaks in sewer pipelines by embedding fibres along the pipeline route and for monitoring the integrity of sewers. The approach is well suited to gravity sewers, where the supply of oxygen can be limited, and the risk of accumulation of toxic and explosive gases is high, this being a hazard to workers and to conventional equipment used in such sewers. Pipelines suffer degradation with time and pipeline bursts and spillages are a potential hazard that will have a negative effect on the environment. This paper will review the design, fabrication, testing and planning for in situ evaluation of several fibre optic sensor systems developed to address the needs of the Australian utility, Sydney Water, for innovative sensor systems that have the capability to be deployed in their network, to ensure that water utilities can mitigate the effect of the ubiquitous microbiologically induced corrosion. Results of current work are presented and future prospects for the technology considered
Recycled Coarse Aggregate from Large-Panel Demolitions in Self-Compacting Concrete: Performance and Sustainability
No full textBuildings constructed with large-panel technology (LPS) before 1990 are increasingly being demolished in Western Europe, and this trend is likely to expand into Central and Eastern Europe due to rising construction activity and limited development space. Despite their age, the concrete from these structures often retains good strength, making it a viable candidate for recycling. This study investigates the reuse of coarse recycled concrete aggregate (RCA) from demolished LPS panels in self-compacting concrete (SCC), a mix known for its high water demand and sensitivity to aggregate properties. The research evaluates whether RCA from LPS should be treated as a distinct material source and examines its effects on cement hydration, free water content, setting times, bleeding, and cross-section homogeneity. While RCA use can reduce the compressive strength of hardened concrete (up to 13% when replacing 30% of natural aggregate), it also improves fresh concrete properties. These include more stable rheology, reduced setting times (by up to 36%), lower bleeding (by up to 40%), and better homogeneity. Strength losses can be mitigated using appropriate pre-treatment and mix design strategies. This study applied a modified Equivalent Mortar Volume (mEMV) method, which improved early compressive strength by up to 10% and 28-day strength by 7%. Given the extensive stock of ageing LPS buildings in Eastern Europe and the ongoing demolitions in the West, RCA offers a sustainable alternative for future concrete production, particularly in SCC, where its benefits in fresh-state behaviour are most pronounced
Co-Creation of Sustainable Concrete for Harsh Environments
No full textThe need to decarbonise construction has intensified interest in low-clinker, high-durability concretes for aggressive environments such as marine and water/wastewater infrastructure. This study presents a co-created research framework combining systematic literature review, stakeholder engagement, and performance-based experimental design to evaluate both conventional and emerging Supplementary cementitious materials (SCMs). SCM selection was guided by oxide composition (CaO/SiO₂, CaO/Al₂O₃), hydration kinetics, durability trends, and industry input. Meta-analyses of acid and sulphate resistance identified key compositional thresholds and performance anomalies, supporting the inclusion of biomass fuel ash (BFA) and limestone calcined clay cement alongside fly ash and GGBS. A standard industry mix (C32/40) was modified with SCMs for compatibility with Irish infrastructure practices. A two-phase lab programme was developed to assess compressive strength, chloride migration, sulphate resistance, and acid durability. While testing is ongoing, early results confirmed structurally viable 28-day strength across all systems. This integrated methodology ensures scientific rigour, field relevance, and regulatory alignment, advancing practical solutions for low-carbon concretes in harsh environments
Advancing Monitoring and Self-sensing Capabilities of Smart Asphalt Concrete containing Conductive Carbon Nanofillers
No full textConventional asphalt pavements can withstand the traffic loading and provide safe, comfortable driving conditions, however, the intelligent functionality on self-monitoring and damage detection is also required for the construction of intelligent transport systems. This study develops a self-sensing conductive asphalt concrete inspired by smart cement-based materials, which is capable of continuous, real-time monitoring of stress, strain, and damage, enabling structural health monitoring (SHM) of asphalt pavements. The self-sensing characteristics relies on the piezoresistive effects that the internal conductive network deforms and causes measurable changes in electrical resistance under mechanical loading. To achieve this, carbon nanomaterials, graphene nanoplates (GNPs) and multi-walled carbon nanotubes (MCNTs), were incorporated into the asphalt matrix to fabricate a conductive asphalt concrete with enhanced conductivity and sensing properties. Results show that the incorporation of GNPs and MCNTs transforms the asphalt mixture from an insulator to a conductor, primarily through the contact between conductive fillers as well as the tunneling mechanism. The GNPs/MCNTs modified asphalt concrete exhibits significant and complicated piezoresistive responses under different loading conditions. This behaviour can be attributed to multiple interacting mechanisms within the conductive network, including proximity effects, microcrack formation, and dislocation of conductive paths, which causes remarkable changes in the electrical resistance under stress
Durability Assessment of Low-Carbon Concrete using Electrical Resistivity and Derived Transport Parameters
No full textEffective assessment of reinforced concrete durability necessitates monitoring of concrete performance using straightforward yet robust technique over an extended period of time. This study investigates six low-carbon concrete mixes incorporating up to 70% Portland cement replacement using binary and ternary combinations of ground granulated blast furnace slag (GGBS), fly ash (FA), and limestone powder (LP). Electrical resistivity measurements were undertaken over a 360-day period and used to derive formation factors and instantaneous diffusion coefficients, offering insight into the evolving pore structure and ionic transport. The results showed that all mixes exhibited a progressive increase in resistivity, indicative of continued hydration and microstructural refinement. The binary FA mix achieved the highest resistivity and formation factor, attributed to its pozzolanic activity, while the PC reference mix exhibited the lowest. Ternary blends of GGBS and FA demonstrated synergistic effects, whereas LP-containing mixes showed limited refinement over a long term, indicating LP’s contribution is primarily physical. It is shown that Formation Factors and instantaneous diffusion coefficients derived from resistivity data provide a means of ranking concrete durability without reliance on extended exposure testing. It is also shown that all low-carbon mixes outperformed the reference PC mix, confirming the effectiveness of SCMs in enhancing resistance to ionic ingress and supporting their use in achieving long-term durability within sustainable construction
Advancing Soil Health Management Through Spatially Optimized Soil Sampling
No full textAccurately monitoring soil health across farms requires sampling designs that capture spatial heterogeneity without excessive cost. Our systematic review of digital soil mapping approaches screened 181 articles and retained 31 for detailed analysis. Most studies either did not optimize sampling spatially or did not report doing so. Four designs dominated: simple random sampling (SRS), stratified random sampling (StRS), spatial coverage sampling (SCS), and conditioned Latin Hypercube Sampling (cLHS). Only 7% of papers explicitly evaluated spatial representativeness before modeling, typically using Bhattacharyya distance (BD) and Kullback–Leibler divergence (KLD).
We validated insights from the review with two case studies using grid soil data from Purdue’s ACRE and SEPAC farms in Indiana. For each site, we generated samples via SRS, StRS, SCS, and cLHS at fractions from 10% to 100% of the full dataset (10% increments) and quantified representativeness with BD and KLD. Across both sites, cLHS consistently produced the lowest BD and KLD, indicating the strongest match to full‐population variability. Results suggest that cLHS can achieve adequate spatial representativeness with ~30% of the full sample size, whereas SRS, StRS, and SCS generally required \u3e60%. These findings provide practical guidance for spatially optimized soil sampling to support reliable, cost-effective soil health assessment
Teaming With Insects: Entomology for Grades 3-12
No full textTeaming With Insects: Entomology for Grades 3–12 is written for youth who enjoy learning about and studying science and nature. Insects have been around for millions of years and have evolved and adapted to many different habitats. Adaptations involving their anatomy, physiology, and behavior are what make insects so diverse and interesting. More than 1 million species of insects are known to scientists, and they believe there may be up to 40 million more we have yet to discover. Most people consider insects pests, and some insects do damage to homes, plants, crops, and stored foods. Others harm humans and animals by biting, stinging, and spreading diseases. The vast majority of insects, however, are beneficial to our ecosystem, and a few, such as honeybees and silkworms, provide direct economic benefits to humans. This book is divided into four easy-to-use sections, each of which is designed with a specific purpose in mind and is tailored to a particular grade level. The first section is geared to students in grades 3 through 5. It introduces young readers to the world of insects, examining their physical appearance and movement. Level 2, intended for individuals in grades 6 through 8, demonstrates how to make insect collection tools and expands on the basic concepts of biodiversity, invasive species, integrated pest management, and forensic entomology. Suited for students in grades 9 through 12, level 3 focuses on using the scientific method, supplying reference materials for personalized learning and further research. The final section presented in Teaming With Insects, the facilitator’s guide, provides suggestions and answers to the youth activities as well as information about working with future entomologists.https://docs.lib.purdue.edu/purduepress_ebooks/1096/thumbnail.jp
Curbless by Design: Revitalizing Downtown Infrastructure for Pedestrians
No full textThis presentation will discuss the design of a curbless, pedestrian-focused corridor as part of a small-town downtown reconstruction in Sylvania, Ohio. The project team will share how they balanced community goals, accessibility, and utility coordination, along with considerations for drainage, hardscape, lighting, and power. The session will also highlight early construction lessons learned from Phase 1
Performance Acceptance and Performance Monitoring of Pavement Using Falling Weight Deflectometer (FWD) and International Roughness Index (IRI)
No full textThe Indiana Department of Transportation (INDOT) utilizes the International Roughness Index (IRI) and Falling Weight Deflectometer (FWD) data to prioritize pavement maintenance across interstates, state roads, and U.S. highways. While IRI measures ride quality and FWD assesses structural integrity, their threshold values vary by road type, reflecting differing service expectations. Effective pavement maintenance requires a holistic approach, combining surface condition data from IRI with structural insights from FWD through predictive modeling. Additionally, these metrics should not only estimate service life but also provide indications of potential distress types, ensuring a comprehensive understanding of pavement performance and maintenance needs. The study employs a dual methodological approach, combining probabilistic and deterministic modeling techniques to evaluate pavement deterioration and predict performance across various road classifications. A Markov chain probabilistic model is utilized to analyze deterioration rates and assess the likelihood of pavements transitioning between condition states (e.g., very good to poor) for each road category. In parallel, an empirical deterministic approach is applied to develop IRI-based prediction models, enabling cross-comparison of degradation trends and steady-state conditions derived from both methodologies. The deterministic approach further investigates the influence of initial IRI on pavement performance, emphasizing its critical role in maintaining functional performance within acceptable limits. Additionally, the remaining service life and life expectancy of pavements are estimated to establish terminal failure thresholds for different road categories. Finally, the study analyzes FWD data from various roads to predict maintenance priorities by establishing a correlation with IRI. The outcome of the study is the expected use of IRI and FWD data to support INDOT’s commitment to proactive pavement maintenance