Search Results (391)

Pervious concrete must balance mechanical capacity with interconnected voids required for drainage. A three-factor, three-level Box–Behnken design examined fly ash (FA; 10–20%), metakaolin (MK; 5–15%), and nano-silica (NS; 0.5–1.5%) at a fixed total binder content of 380 kg/m³. Compressive strength, water-accessible open porosity, and the apparent permeability coefficient ranged from 16.80 to 28.20 MPa, 14.07 to 24.50%, and 2.20 to 7.29 mm/s, respectively. Quadratic models for compressive strength and the apparent permeability coefficient were statistically adequate (R² = 0.9907 and 0.9861); the porosity model showed significant lack of fit. The porosity model was retained only for local trend interpretation and excluded from optimization. In a researcher-defined design scenario that maximized strength while targeting an apparent permeability coefficient of 3.00 mm/s, desirability analysis selected a model-predicted compromise solution containing 14.038% FA, 12.556% MK, and 1.483% NS, with a predicted compressive strength and an apparent permeability coefficient of 28.233 MPa and 3.000 mm/s. The NS factor was close to the upper boundary, and the solution was not experimentally validated. Selected single-field SEM observations illustrated local differences among M5, M7, and M12, while selected-area EDS sum spectra provided only local elemental composition information. The results indicate potential for future pavement evaluation after independent validation, multi-field microstructural analysis, durability testing, and economic assessment. Full article

Interlocking permeable pavements (IPPs) are increasingly adopted within sustainable urban drainage systems to reduce runoff, improve water quality, and strengthen climate-resilient urban infrastructure. However, clogging remains the principal constraint on their long-term hydraulic performance and wider implementation. This review synthesises current evidence on clogging mechanisms, hydraulic decline, and lifecycle mitigation strategies for permeable interlocking concrete pavements (PICPs), concrete grid pavements (CGPs), and plastic grid pavers (PGPs). The literature is dominated by PICP studies, with CGP and PGP underrepresented, restricting typology-specific assessment. Sediment accumulation within joints, grid openings, bedding layers, and near-surface interfaces is consistently identified as the primary clogging mechanism, while traffic, rainfall-runoff loading, biological processes, pollutant retention, and sediment inputs from adjacent impervious surfaces further influence hydraulic deterioration. The findings indicate that hydraulic performance is influenced not only by pavement age but also by interactions among pavement design, filler or joint material, drainage configuration, construction quality, sediment exposure, monitoring, and maintenance. Effective mitigation therefore requires lifecycle management, encompassing source control, pretreatment, appropriate material selection, construction quality assurance, routine hydraulic monitoring, and timely preventive and restorative maintenance. Future research should prioritise standardised clogging assessment protocols, improved laboratory–field integration, targeted investigation of CGP and PGP, biological and pollutant-linked clogging processes, climate-driven rainfall extremes, and decision-support. Full article

The paper investigates the integration of permeable pavements into sustainable urban mobility planning in Bologna, Italy. The study evaluates stormwater management benefits under the current and future climate conditions through hydrological and hydraulic modeling with EPA SWMM. A residential catchment of about 50 hectares was analyzed, with potential permeable pavement implementation on pedestrian paths and parking areas. Results show a 40% reduction in stormwater volumes under the current climate and 38% under future scenarios, confirming the resilience and effectiveness of green infrastructure. Findings support Bologna’s Urban Plan for Sustainable Mobility, highlighting permeable pavements as a strategy to enhance resilience and sustainability. Full article

Wicking geotextiles are specialized geosynthetics designed to regulate soil moisture through a combination of capillary-barrier and lateral-drainage mechanisms. Laboratory and field studies demonstrate their effectiveness in reducing volumetric water content, restricting capillary rise, and maintaining subgrade and base stability under rainfall, dry–wet cycles, freeze–thaw cycles, and traffic loading. Performance is influenced by soil type, fines content, installation depth, edge exposure, and environmental conditions. Field applications show benefits in pavements, expansive soils, pumping-prone sections, cold-region roadbeds, and permeable urban infrastructure. Multi-layer and composite geotextiles further enhance hydraulic and mechanical performance. Despite these advantages, gaps remain in standardized testing, long-term monitoring, design methods, and durability assessments under aggressive conditions. This review synthesizes recent experimental and field evidence, highlighting mechanisms, performance factors, and research needs to guide the optimal design and application of wicking geotextiles in geotechnical engineering. Full article

Rapid peri-urban sprawl is intensifying flood risk by replacing natural landscapes with dense, impervious residential developments. Thailand’s land use regulations require a 5% minimum green space allocation for new housing developments as a measure to promote livability and well-being. Green space also has the potential to sustainably manage stormwater runoff, but for Thailand’s peri-urban development, the question remains whether 5% green space is sufficient to reduce flood risk. As such, this study critically evaluates whether this 5% green space guideline is sufficient for peri-urban runoff and flood management in peri-urban Pathum Thani, particularly given the acceleration of Bangkok’s urban sprawl over the past 30 years. Using a multi-scalar framework, we integrated GIS spatial analysis of 164 gated communities (1995–2025) with site-specific PCSWMM hydrologic modeling to test baseline conditions and Nature-based Solution (NbS) interventions against 5-, 10-, 50-, and 100-year design storms. Findings reveal developers generally adhere to the 5% guideline, thereby addressing policy while maximizing salable land space. PCSWMM simulations show the 5% baseline alone does not adequately manage runoff, with localized residential flooding expected for a 5-year design storm under current baseline conditions. Scenario testing indicates a hybrid grey–green infrastructure approach would optimally manage flooding. Given economic barriers to expanding open space, converting roads to permeable pavements offers a possible optimization strategy. Ultimately, static area-based regulations remain insufficient; policies must transition to performance-based volumetric retention targets to mitigate downstream flooding and foster resilient communities. Full article

Air-void distribution is an important internal characteristic of asphalt mixtures, as it affects compaction quality, moisture susceptibility, permeability, and long-term pavement durability. Conventional air-void testing methods generally provide only an average volumetric parameter and cannot effectively describe the spatial distribution of air voids within cylindrical specimens. To address this limitation, this study proposes a capacitance-based method for characterizing the vertical and radial air-void distribution of asphalt mixtures using a saturated reference field. An annular capacitive sensor was designed for cylindrical asphalt mixture specimens, and its structural dimensions were optimized using capacitance sensitivity and sensitivity-field distribution uniformity as evaluation indicators. Asphalt mixture specimens with different gradations and compaction conditions were prepared and tested under a saturated reference-field measurement scheme. Dielectric indicators derived from capacitance measurements were used to characterize the variation in air-void distribution along the specimen height and across radial regions. Layer-wise air-void measurements were further conducted to validate the vertical distribution results, while radial partition-based indicators were introduced to quantitatively describe the air-void distribution characteristics from the center to the edge of the specimen. In addition, rotation-angle and saturated-condition stability tests were performed to evaluate the robustness of the proposed method. The results indicate that the saturated reference-field capacitance method can effectively reflect the spatial variation in air voids in asphalt mixtures and provides a low-cost, rapid, and non-destructive approach for evaluating air-void distribution characteristics in laboratory-compacted specimens. Full article

This study presents a photocatalytic infiltration pavement block designed to combine roadside NO_x removal with rainwater capture and temporary storage. TiO₂ and styrene–butadiene rubber (SBR) latex were incorporated into the pavement block to provide photocatalytic functionality, and direct infiltration holes were introduced to capture surface runoff, enable temporary storage, and promote delayed subgrade drainage. The effects of TiO₂ and SBR latex on compressive strength and NO_x removal were evaluated, while rainwater infiltration performance was examined using acrylic panels with different hole diameters, hole-area ratios, slopes, and V-groove treatments. The use of SBR latex improved the compressive strength of TiO₂-containing mixtures, with T10-L5 showing an 8.1% increase compared with the corresponding non-latex mixture. The same mixture achieved the highest NO_x removal efficiency, reaching 73.0% after 60 min of UV exposure. In the infiltration test, the 5 mm hole configuration gave the most stable runoff reduction, and lattice-type V-grooves improved water capture by connecting adjacent holes and guiding surface flow. A field-scale trial installation confirmed that the integrated infiltration–retention system suppressed visible ponding and runoff, provided delayed subgrade drainage, and maintained pavement stability under vehicle loading. The findings indicate that the proposed block system can provide combined air-purification and stormwater-control functions. Full article

Rapid urbanization has intensified two critical urban challenges: the urban heat island effect and stormwater runoff. This study evaluates the pilot-level field performance of a low-tortuosity permeable pavement (LTPP) system in potentially contributing to improved thermal regulation and hydraulic functionality. The system comprises a reduced-tortuosity upper block incorporated with bottom ash (BA) as a recycled fine aggregate and an underlying storage unit connected through an interlocking configuration, enabling direct infiltration while reducing clogging susceptibility and improving resistance to settlement and displacement. Field tests included thermal imaging, water-spraying infiltration-storage and vehicle-loading observations, and theoretical storage analysis. Initially, conventional permeable pavement (PP) dry surface temperature was measured at 44.2 °C, whereas the LTPP system already exhibited a lower temperature of 42.4 °C. During the evaporative stage after wetting, the LTPP system showed a lower temperature recovery rate, with a 2.91% increase between 90 and 120 min compared with 3.60% for conventional permeable pavement, indicating improved surface-temperature regulation. The storage calculations approximated that the LTPP system could theoretically buffer the simulated 15.63 mm/h rainfall by 6.65 to 7.32 h. It was also determined using historical rainfall data that the LTPP system, especially when provided with an outlet or drainage system, could effectively accommodate short- to medium-duration rainfall. Water-spraying tests confirmed rapid infiltration and subsurface storage, while vehicle-loading observations showed no noticeable displacement or settlement. These findings highlight the potential of a multifunctional permeable pavement design strategy that combines low-tortuosity flow paths, functional recycled aggregate selection, and subsurface storage for surface-temperature regulation and stormwater management. Full article

Urban development increases impervious surfaces and stormwater runoff, while the construction sector generates large volumes of construction and demolition waste (CDW). Pervious concrete can mitigate runoff through infiltration and may also valorize CDW, yet its production and testing procedures remain heterogeneous, particularly with recycled aggregates. This study experimentally screens practical processing parameters for pervious concrete produced with basalt and CDW coarse aggregates. The influence of chemical admixture, consolidation method, and end-surface preparation was first assessed to define suitable production conditions: adequate cohesion without admixture required raising the water-to-cement ratio from 0.30 to 0.65; high-energy Proctor compaction crushed the CDW aggregates, favoring standard tamping-rod consolidation; and end-surface preparation had only a minor effect on compressive strength. The selected procedures were then applied to an ACI 522R-based basalt mixture designed for a target void content of 25%, which achieved a fresh density of 1985 kg/m³, a void ratio of 16.88%, and a mean permeability coefficient of 12.18 × 10⁻³ m/s, about twelve times the minimum required by ABNT NBR 16416. Its 28-day compressive strength (12.75 MPa) remained below the 20 MPa pavement-surfacing requirements, although within the typical range reported by ACI 522R for pervious concrete (2.8 to 28 MPa). Overall, aggregate gradation, compaction procedure, and admixture-enabled paste cohesion emerged as the dominant factors governing the strength–porosity–permeability trade-off, guiding subsequent mix optimization. Full article

Against the backdrop of China’s dual-carbon strategy and the development of green transportation, systematic research on direct pavement carbon absorption and sequestration remains limited. Traditional epoxy resin coatings, owing to their dense structure, poor air permeability, and single functionality, fail to meet the requirements for pavement carbon absorption. To address this issue, an ordered, honeycomb-like, porous epoxy carbon-absorbing coating was prepared using bisphenol A epoxy resin as the matrix and diethylenetriamine as the curing agent through the breath-figure method. The pore-formation mechanism and the process regulation principles of the coating were systematically elucidated. Key preparation parameters (ambient humidity, dispersion concentration, and spray dosage) were regulated, and multiple microscopic characterization methods, including SEM, FTIR, and TG, were adopted to comprehensively explore the influences of preparation parameters on the coating’s microstructure, chemical composition, and thermal stability. Experimental results indicate that under optimized process conditions, a honeycomb-like porous coating with uniform pore size and regular arrangement can be fabricated. The fabrication procedure features simple operation, favorable controllability, and low cost. The breath-figure method was successfully applied to the preparation of a porous epoxy carbon-absorbing coating, achieving controllable regulation of the porous structure and thereby effectively overcoming the limitations imposed by the dense nature of traditional epoxy coatings. Consequently, this work provides new technical concepts and data support for the development and application of low-carbon functional coatings for pavements. Full article

Porous asphalt (PA) mixtures offer multifunctional benefits, yet their long-term durability remains a challenge. This study presents a systematic review of recent developments in waste-modified PA, following PRISMA guidelines and analyzing 123 high-impact documents published between 2015 and 2025 across the Web of Science and Scopus databases. Unlike previous works, this paper adopts a multi-waste perspective to synthesize the interactions between recycled modifiers and the open-graded skeleton. Quantitative analysis reveals that incorporating crumb rubber can improve sound absorption by up to 30%, while specific recycled plastics enhance rutting resistance by 15–20% compared to conventional mixtures. However, Life Cycle Assessment (LCA) data indicates that these environmental gains, reducing carbon footprints by up to 25%, are highly sensitive to the chosen system boundaries. The review identifies a critical need for standardization in clogging protocols and ‘cradle-to-grave’ environmental modeling to bridge the gap between laboratory results and large-scale engineering practice. Finally, this research demonstrates how the adoption of waste-modified porous asphalt mixtures directly contributes to the United Nations Sustainable Development Goals (SDGs), particularly SDG 9 (Industry, Innovation, and Infrastructure), SDG 11 (Sustainable Cities and Communities), and SDG 12 (Responsible Consumption and Production), by fostering circular economy principles in pavement engineering. Full article

The intensification of the urban heat island effect poses a critical threat to the preservation and habitability of compact historic districts. The Alameda de Hércules in Seville exemplifies this vulnerability, where the intersection of heritage protection and extreme Mediterranean summers limits conventional climate adaptation. This study conducts a multi-temporal evaluation of the square’s climate resilience, spanning from its configuration prior to major 21st-century renovations to its current state and future projections, proposing future interventions. By integrating advanced microclimatic simulation and high-fidelity energy modeling, the research assesses a dual-function strategy: the improvement of the thermal environment while implementing non-intrusive photovoltaic pavements (PVPs) for energy generation. Environmental parameters, including air temperature, mean radiant temperature (MRT), and the universal thermal climate index (UTCI), were analyzed alongside the renewable energy potential of the site’s mobility infrastructure. Four heritage-sensitive interventions were tested: PV-integrated bicycle lanes, shading canopies, reflective pavement, and permeable paved grass. The results demonstrate that the canopies and paved grass zones can lower surface temperature up to 3.7–4.3 °C, reduce UTCI stress up to 2.3–3.0 °C, and decline MRT up to 10.6 °C. These values correspond to the maximum reductions achieved in specific zones. However, the PVP can locally increase surface temperature by about 4.7 °C and the reflective pavements increase MRT by around 10.4 °C, while generating an estimated annual energy yield of 174.19 MWh. The analysis under future climate projections suggests that these strategies remain equally effective under future scenarios. These findings confirm that PV-integrated urban surfaces offer a viable, reversible, and replicable approach to retrofitting historic public spaces, harmonizing climate-adaptive cooling with decentralized energy production without compromising the site’s cultural significance. Full article

Indian metropolitan cities such as Mumbai grapple with rapid urbanisation, extreme urban density, high built-up areas, loss of green cover, and shrinking open spaces, resulting in increased impermeable surfaces, urban heat island effects, and frequent flooding occurrences. Modern stormwater management has increasingly been characterised by integrated grey-green approaches; however, cities in the Global North benefit from established policies, technical expertise, and financial resources that enable the systematic and large-scale integration of Blue-Green Infrastructure (BGI) through district-wide geospatial assessment frameworks, unlike many cities in the Global South. Despite growing interest in nature-based stormwater solutions, there remains a dearth of geospatial empirical research from India examining the placement, distribution, performance, and functionality of BGI integrated with existing stormwater management systems in cities such as Mumbai. Furthermore, hydrological modelling using tools such as the Storm Water Management Model (SWMM) for the design, planning, and implementation of BGI in Indian cities remains largely unexplored. This study explores the role of BGI strategies in improving urban stormwater management within high-density Indian cities under a 25-year return period extreme rainfall scenario. Using an integrated approach that combines QGIS-based spatial analysis with EPA-SWMM hydrologic-hydraulic modelling, the research examines runoff behaviour, identifies flooding hotspots, and evaluates the effectiveness of Low Impact Development (LID)-based BGI measures such as permeable pavements, infiltration trenches, and green roofs applied at the ward level in Mumbai’s F/North and G/North Wards. Detailed land use classification, spatial mapping, and rainfall simulation corresponding specifically to a 25-year return period rainfall event was used to assess pre- and post-intervention conditions. The findings indicate that the applied BGI measures led to a 12.6% reduction in peak runoff (137.6 m³/s to 120.2 m³/s) and a 5.5% decrease in total runoff volume (783,510 m³ to 740,410 m³). More importantly, the peak flooding flow rate decreased by 45% (94.1 m³/s to 51.7 m³/s), demonstrating that BGI measures can efficiently reduce peak flooding flows by extending runoff hydrographs during extreme rainfall events. These findings are specifically applicable to the simulated 25-year return period extreme rainfall scenario and may vary under different rainfall intensities or return periods. Less extreme events could potentially experience even greater relative reductions or prevent flooding altogether, while also easing downstream hydraulic loads. Overall, strategically placed BGI interventions can significantly reduce surface runoff and peak flow, thereby enhancing stormwater resilience within spatially constrained urban environments. This study provides a replicable, data-driven framework for catchment-scale stormwater planning in dense Indian cities under extreme rainfall conditions, offering practical insights into methods, local contextual considerations, and spatial planning strategies for policymakers and urban planners seeking to retrofit and adapt existing infrastructure under increasing hydrologic stress and climate variability. Full article

Permeable pavements offer a dual-function solution, converting hardstanding into active stormwater control, yet field performance data under real rainfall remain limited. Unlike laboratory-based studies, this research captures in situ hydrological behaviour under natural rainfall variability. This study monitors the hydrological performance of a full-scale permeable pavement system at Heriot-Watt University, Edinburgh, over seven months, using paired rainfall and underdrain outflow measurements. Monthly water balance metrics, including retained depth and retention ratio, were derived from April to October. Results show the strongest volume retention during moderate-rainfall months, peaking at 18.7% in July, with an overall monitoring-period retention of 4.9%. Negative retention ratios in May and August reveal inter-event sub-base drainage dynamics that monthly metrics alone cannot fully resolve. Weekly hydrograph analysis identified two distinct hydraulic regimes: sub-base attenuation under low-to-moderate rainfall and near-direct underdrain transmission when antecedent wetness exhausted storage capacity. These findings demonstrate that the antecedent moisture condition is the primary control on the hydraulic regime, with implications for SuDS design and performance monitoring in temperate climates. Full article

Flexible base layers can improve deformation compatibility and reduce reflective cracking in asphalt pavements, but conventional graded crushed stone is limited by weak interparticle bonding, poor water stability, and insufficient resistance to permanent deformation. Solution Road Soilfix (SRX) is a water-based polymer stabilizer used to improve the engineering performance of graded crushed stone by enhancing interparticle bonding. This study investigated the effects of SRX dosage, aggregate gradation, degree of compaction, and curing conditions on the load-bearing capacity and pavement performance of SRX-stabilized graded crushed stone. The results showed that SRX stabilization significantly improved the California bearing ratio (CBR), water stability, and permanent deformation resistance of the graded crushed stone mixture, although its permeability decreased due to polymer coating and void filling. At an SRX dosage of 0.50% by dry aggregate mass, the CBR values exceeded 300%, while further dosage increases provided only limited additional improvement. Among the three gradations, the 26.5 mm gradation exhibited the best overall performance due to its balanced coarse aggregate distribution and stable interlocking skeleton. CBR was highly sensitive to the degree of compaction, and a field compaction degree of at least 98% is recommended. Oven curing at 50 °C accelerated moisture evaporation and SRX film formation; the 6-day CBR exceeded 80% of the 30-day reference strength and correlated well with long-term strength. Overall, the recommended parameters are 0.50% SRX dosage, 26.5 mm maximum aggregate size, compaction degree ≥ 98%, and oven curing at 50 °C for 6 days before laboratory CBR evaluation. Full article