Street Pavements Research Articles

The role of engineered tree pit solutions in nature-positive civil engineering

Successfully establishing and growing street trees presents significant challenges and traditional techniques are associated with elevated tree mortality. Moreover, securing appropriate soil volumes for trees is a substantial challenge, particularly in modern street engineering where the grey infrastructure is prioritised over tree success. Engineered tree pit solutions can counteract this situation. They enable trees and grey infrastructure to coexist, providing improved rooting environments, load-bearing structural support conforming to engineering specifications, and the ability to manage stormwater runoff within one tree pit design. This article presents a literature-informed overview of the current technologies applicable to new-build and retrofit scenarios that integrate street trees and pavements, enabling nature-positive, resilient tree pit designs conducive to tree growth. We focus on the solutions most commonly employed in practice – structural growing media and crate systems – outlining their constituents, construction and considerations for success. This article informs built environment practitioners, policymakers and researchers on innovations translatable into practical techniques to enhance tree pit design and optimise street trees as multifunctional nature-based solutions.

Photoluminescent Applications for Urban Pavements

Photoluminescent materials used on street and road pavements could absorb solar energy during the day and emit it at night, which will save energy and improve visibility with a consequent improvement in road safety. The aim of this study is to evaluate the luminance of different photoluminescent applications for pavements (bituminous mixes, mortars, and paints) in which strontium aluminate and glass beads were used. Sunlight was simulated with two bulbs, one LED and one UV bulb, inside a measuring apparatus specially developed for this work. The luminance of the different designed solutions was determined at different time periods after their excitation. The results obtained showed that luminescent paints can reach higher luminance than bituminous mixes and mortars. The colour of the base surface on which the paints are applied had a great influence on the obtained luminance, which increases with the aluminate and glass beads content. Among all the solutions evaluated, the paint made with 60% aluminate and 6% glass beads, spread on a white surface, allowed the highest luminance values to be obtained. This study leads to the conclusion that it is possible to achieve a good photoluminescent level while economising on the amount of materials necessary.

Street Pavements: A Physical Reflection of Street Democracy

Street democracy as an aspect of urban democracy, has been seminal to urban design for over 50 years. Good street democracy requires more inclusion on the street, which helps keep a good public realm for a place. This paper reviews existing discussions of street democracy from peoples right to the city and develops the discussion of street democracy related to street pavements. Street pavement should be considered an aspect of street democracy. Street pavement could positively reflect street democracy in a city. This study selects two streets in Cardiff as examples to study their existing street pavement conditions from local and regional policies and observe the changing of street pavements in specific areas during the last decade. The paper advocates for the improvement of street democracy with the development of street pavement in different periods. A good street democracy should have more inclusion and democracy is changing progress for different conditions during different periods.

Sustainable Mitigation Strategies for Urban Heat Island Effects in Urban Areas

The globe is at a crossroads in terms of the urban heat island effect, with rising surface temperatures due to urbanization and an expanding built environment. This cause-and-effect connection may be linked to weather-related dangers, natural disasters, and disease outbreaks. Urbanization and industrialization will not lead to a secure and sustainable future. Finding solutions to problems such as the heat island effect is at the forefront of scientific research and policy development. Sustainable ways to decrease urban heat island impacts are a core principle for urban planners. This literature study examines the benefits of adding green infrastructure and sustainable materials in built-up areas to reduce the urban heat island effect. Materials such as reflective street pavements, coating materials including light-colored paint, phase-change materials, color-changing paint, fluorescence paint, and energy-efficient appliances are considered sustainable materials, whereas green infrastructure like green roofs, green walls, green parking and pavements, and shaded streets are considered to mitigate the urban heat island effect. The hurdles to the widespread adoption of such practices include a lack of governmental legislation, insufficient technological development, an erroneous estimation of economic gains, and unwillingness on the part of impacted parties.

Mechanical performance of fiber-reinforced polymer tank under road pavements for stormwater storage

Due to increasing precipitation intensity, rising sea level, and land development, urban flooding has become a major issue in many places around the world. This research aims to develop underground storage tanks (USTs) using fiber-reinforced polymer (FRP) materials for stormwater detention, storage, and reuse. The USTs are intended to be placed underneath highway or street pavements. FRP as one of the emerging structural materials possesses several advantages including high strength-to-weight ratio and corrosion resistance. The mechanical performance of USTs has rarely been visited in the literature, the majority of which focuses on leakage issues and associated environmental problems. This paper presents detailed analyses of the mechanical performance of FRP USTs, including a laboratory test on a small-scale FRP UST and a verified finite element (FE) analysis on full-scale FRP USTs. The influences of various factors on the mechanical performance of the USTs were examined, including wall thickness, water storage, interfacial roughness between FRP and soil, and tank sizes. Both results from experiments and FE studies agree satisfactorily and reveal that (i) underground FRP UST developed tensile axial strains at the top surface at the mid-span of the tank and the side surface at the mid-height; (ii) compressive axial strains developed in most of the cap region; and (iii) large compressive circumference strains developed in the FRP UST in most locations. Insights gained from the laboratory test and the FE analysis are expected to provide a general guidance on the design of FRP USTs under road pavements for urban flooding mitigation and stormwater harvesting.

Analysis and study of the migration pattern of microplastic particles in saturated porous media pavement

This work aims to establish an analytical and comparative model of pavement stormwater runoff and determine how to solve water pollution in saturated porous media pavements. Heavy metal element particles in the stormwater runoff due to the rainfall will cause inevitable environmental pollution. First, the pavement runoff and materials of saturated porous media are analyzed. Besides, particle migration laws and separation effects of different materials are compared. Based on this, microplastics are selected as the primary material for pavement filling. Then, the adsorption effect of microplastics and the parameters of rainwater infiltration rate and infiltration ratio are analyzed to propose a multi-level ecological integrated treatment system for pavement runoff. Specifically, the environmental resource pollution and saturated porous media materials are analyzed. In addition, the adsorption effect of microplastic particles is analyzed to establish a model to study the selection process of the optimal adsorption material. The main contribution of the research is to analyze the migration process of metal particles in the soil in combination with the internal particle migration rules of plastic granular materials. The research results demonstrate that the rain runoff coefficient gradually increases with the expansion of the permeable area of the pavement. The rain runoff coefficient reaches the maximum value under the pavement of 120 square meters. In addition, a comparative analysis of three street pavements is conducted on the residential street pavement (RSP), commercial street pavement (CSP), and active street pavement (ASP). When comparing the two sets of data, the overall average permeability of the RSP is better than CSP and ASP. The research materials are compared under isothermal conditions. The particle adsorption effect of the same material at 50 °C is significantly better than that at 30 °C. Therefore, it is feasible to resolve the pavement runoff water pollution through technical schemes.

Life cycle assessment (LCA) of precast concrete blocks utilizing ground granulated blast furnace slag.

Concrete paving block (CPB) has become a popular construction material for pavements subjected to passive loads (parking, toll plazas, gas stations, and street pavements). Due to the short time in the production of CPB, the concrete block industry has experienced tremendous growth over the past decade. In this scenario, the environmental distress cannot be ignored due to the increased extraction of raw materials (fossil fuels, limestone, river sand, and crushed aggregates) in the manufacturing of CPB. The sustainability issues demand the utilization of eco-friendly materials instead of natural ones to minimize the abiotic depletion caused by the construction industry. This study investigates the technical and environmental performance of CPB production incorporating an eco-friendly mineral admixture, i.e., ground granulated blast furnace slag (GGBS), as a cement replacement material. The optimum level of GGBS was decided based on the required engineering performance and minimal environmental impact. For the determination of the engineering performance of CPB, several parameters were considered such as compressive strength (CS), impact toughness (IT), and water absorption (WA). The environmental impact of Global Warming Potential (GWP) was assessed based on a cradle-to-gate LCA analysis. The results suggested that maximum mechanical performance and minimum GWP can be simultaneously achieved at 5-10% replacement of cement with GGBS, while to satisfy the minimum strength requirement, CPB can be prepared using 25% GGBS as a replacement for cement that accounts for 17% lower GWP than that of the conventional CPB manufacturing.

Urban pedestrian stone pavements: measuring functional and safety requirements

ABSTRACT Urban street pavements have historically represented the synthesis of functional and aesthetic values, capable of meeting the transportation needs and demands in which the pedestrian is always put at the centre of the project. The quality of a pedestrian-priority space must be read according to a series of specific indicators that combine the unbeatable aesthetic requirements with those of comfort and safety. To this end, an integrated approach of experimental measurements to characterise the quality of pedestrian paths (pedestrian-only streets, sidewalks, shared areas and plazas), with specific attention to stone and segmental pavements, was introduced. The different effects, in terms of vibrations and noise, that the pavement of a pedestrian path can generate on a user pulling a suitcase trolley (telescopic handle wheeled luggage), were evaluated. These values were than associated with other parameters capable of describing the characteristics of the pavement surface, such as surface macro- and micro-roughness, skid resistance and size of the elements and joints that make up the pavements. Comfort and safety thresholds for pedestrian street pavement surfaces have been identified. They can be usefully made available to designers for the functional characterisation of urban paving solutions, with particular attention to those in natural stone.

Effect of metakaolin-based geopolymer concrete on the length of rigid pavement slabs

Rigid pavement is one of the pavement methods used specially in high traffic zones. Up till now, Portland cement concrete (PCC) is the most commonly used material for rigid pavement. One of the problems that faces PCC is the allowable spacing for transverse joints in rigid pavements’ plain concrete slabs. As recommended by different standards and design manuals, the recommended length of slabs is about 4.5–5 m (In PCA, Thickness Design for Concrete Highway and Street Pavements. Engineering Bulletin EB109P. Skokie, IL, (1984); In ECP, Egyptian code of practice for urban and rural roads part 4: road material and its tests. Housing and Building National Research Center, Egypt, (2018); In FDOT, Rigid Pavement Design Manual. Pavement Management Office, Document No. 625-010-006-e, Tallahassee, Florida, (2009)), this is referred to the thermal volumetric changes in PCC. The low allowable transverse joints spacing in rigid pavement reduces the implementation rates and increases the cost. Geopolymer concrete (GPC) is one of the innovative types of concrete that is eco-friendly than gain early strength in ambient temperature and can gain higher strength by heating. In this research, GPC was investigated to determine its drying shrinkage and thermal expansion behavior and therefore affect the length of concrete slabs in rigid pavement. This different type of concrete showed an acceptable performance against drying shrinkage and thermal expansion more than PCC.

Smart wetting of permeable pavements as an evaporative-cooling measure for improving the urban climate during heat waves

An urban microclimate model is used to design a smart wetting protocol for multilayer street pavements in order to maximize the evaporative cooling effect as a mitigation measure for thermal discomfort during heat waves. The microclimate model is built upon a computational fluid dynamics (CFD) model for solving the turbulent air, heat and moisture flow in the air domain of a street canyon. The CFD model is coupled to a model for heat and moisture transport in porous urban materials and to a radiative exchange model, determining the net solar and thermal radiation on each urban surface. A two-layer pavement system, previously optimized for maximal evaporative cooling applying the principles of capillary pumping and capillary break, is considered to design a smart wetting protocol answering the questions “when,” “how much,” and “how long” a pavement should be artificially wetted. It was found for the current optimized pavement solutions that a daily amount of 6 mm wetting over 10 min in the morning, preferentially between 8:00 and 10:00, guarantees a maximal evaporative cooling for 24 h during a heat wave.

Hazardous thoracic and ultrafine particles from road dust in a Caribbean industrial city

In this study, inorganic geochemical characterization of the thoracic (or < 10 μm) fraction of road dust in Barranquilla (a major industrial city in the Caribbean region) was conducted. Samples were collected directly from street pavements, and the fraction of particles <10 μm was analyzed by inductively coupled plasma - optical emission spectroscopy (ICP-OES) and inductively coupled plasma - mass spectrometry (ICP-MS). Major elements including Al, Ca, Fe, K, Mg, Na, and S were the most abundant species, accounting for 23 ± 18% of the mass of thoracic particles. Enrichment factor was calculated obtaining that Sb, Sn, Cu, Zn, Pb, and Fe had a dominant anthropogenic influence. An exploratory analysis of morphology and geochemical composition of ultrafine particles was conducted using a field emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HR-TEM). Iron particles were identified as enriched compounds and as a mineral (magnetite). Hazardous ultrafine particles (UFPs, with diameter < 100 nm) such as TiO2 and Pb (agglomerated shape), and V and Ni (almost-spherical carbonaceous particles) were also detected. The braking process was identified as a crucial urban source of thoracic particles and UFPs. The results provide data that can be used to better understand and manage road dust.

Design of smart wetting of building materials as evaporative cooling measure for improving the urban climate during heat waves

An urban microclimate model is used to design a smart wetting protocol for multilayer street pavements in order to maximize the evaporative cooling effect as a mitigation measure for thermal discomfort during heat waves. The microclimate model covers a computational fluid dynamics (CFD) model for solving the turbulent air, heat and moisture flow in the air domain of a street canyon. The CFD model is coupled to a model for heat and moisture transport in porous urban materials, to a radiative exchange model, determining the net solar and longwave radiation on each urban surface and to a wind driven rain model able to determine the wetting flux on each surface during a rain event. We first evaluate the evaporative cooling potential for different pavement systems during normal summer conditions after a long rain event during night in order to select an optimal pavement system. Then, we design a smart wetting protocol answering the questions ‘when’, ‘how much’ and ‘how long’ a pavement should be artificially wetted for having a maximum cooling effect. We found that a daily amount of 5mm wetting over 10 minutes in the morning, preferentially between 8:00 and 10:00 am, guarantees a maximal evaporative cooling for one day and night during a heat wave.

Pebbles of progress: streets and urban modernity in early Meiji Tokyo

This article charts the improvement of street pavements in Meiji-period (1868–1912) Tokyo as a methodological case study for re-situating material objects at the center of historical narrative. So-called “broken stone” pavements – more colloquially known as “macadam” – surfaced the streets of modern capitals around the world by the latter half of the nineteenth century. As Japanese officials set about fashioning their own modern capital following the Meiji Restoration of 1868, they started at street level by repaving select passageways into properly macadamized boulevards. In doing so, they sought to produce streetscapes that would resemble other modern capitals both in appearance and commercial vitality, thereby mediating in the built forms of the capital the prestige and progress of the new capital Tokyo, the fledgling Meiji government, and the nascent Japanese nation beyond. Macadam, then, was a key material object of Japanese modernization in the Meiji period, and one that not only symbolized Japan’s importation of western technology but also embodied its attempts to catch up to the west in terms of wealth and “material civilization.” Study of macadam paving in Meiji Tokyo thus usefully reminds scholars to consider the materials that made larger historical processes work. That is, materials matter.

Impact of retro-reflective glass façades on the surface temperature of street pavements in business areas of Singapore and Tokyo

This study evaluates variations in the surface temperature of street pavements caused by retro-reflective glass when applied on highly-glazed façades of high-rise buildings located in Singapore and Tokyo. To accomplish this, simulations are conducted on one experimental site situated in business areas of Singapore and another in the city centre of Tokyo. Incoming solar radiations on street pavements and heat transfers affecting their surface temperature are among the physical phenomena being simulated. As a result of the data analysis, it appears that the use of accordion retro-reflective glass on highly-glazed façades could noticeably reduce the surface temperature of street pavements in business areas of both Singapore and Tokyo, compared with other types of glass. A more significant decrease in the surface temperature can be expected in the experimental site of Tokyo, particularly near the summer solstice. On the other hand, the design optimisation of accordion retro-reflective glass seems to be more effortlessly achieved in Singapore. These outcomes represent an encouraging step towards the reduction of building energy use, as well as the mitigation of the Urban Heat Island effect, from the use of retro-reflective glass façades in business areas of different cities experiencing various climates.

Mitigating the urban heat island in a residential area in Tehran: Investigating the role of vegetation, materials, and orientation of buildings

The results of researches on the urban heat island (UHI) effect and global warming have attracted more attention to the outdoor thermal comfort. This research evaluates the different strategies for daytime UHI mitigation due to thermal comfort conditions in Tehran which is affected by urban warming. The effects of urban vegetation (on the street level and on the roofs), high albedo surfaces (on the street pavements and on the roofs) and the orientation of buildings are analyzed through numerical simulations using the ENVI-met (version 4.3.0) microclimate model. In this study, an evaluation is carried out using various parameters including air (Ta) and surface temperatures (Ts), sky view factor (SVF), wind speed (WS), mean radiant temperature (MRT) and physiological equivalent temperature (PET). The results indicate that proper design of urban forms would largely mitigate UHI especially for new sustainable developments while thermal comfort improvements can be effectively achieved by increasing the urban vegetation coverage. Also the results demonstrate that there is no significant relationship between the UHI mitigation, and the improvement of thermal comfort. However, if lower surface temperatures are assumed as the basis for the UHI mitigation, a stronger correlation between UHI effect and thermal comfort can be observed.

Effect of Panel Size and Radius of Relative Stiffness on Critical Stresses in Concrete Pavement

Design of concrete pavements is carried out with the help of available guidelines that are generally based on single size of slab panel. However, in practice, the slab size is seen to be different than the one recommended by most of the guidelines such as PCA (Thickness design for concrete highway and street pavements, Portland Cement Assosiation, Skokie, 1984) and IRC 58 (Guidelines for the design of plain jointed rigid pavements for highways, 4th Revision, Indian Road Congress, New Delhi, 2015) , especially on curves or at the junctions. It is also established that temperature stresses vary with the plan size of the panel. The important parameter in the design of concrete pavement is critical edge stress which depends on traffic and temperature load. However, it is observed that, for the same design parameters such as traffic load and subgrade stiffness of soil, critical stress values alter largely as the panel size is diverse from the standard one. The standard panel size as specified by PCA (1984) and IRC 58 (2015) is 3.5 m $$\times $$ 4.5 m. In this paper, the effect of the size of slab panel and radius of relative stiffness on critical edge stress has been investigated. Analytical models have been developed to obtain critical edge stress for concrete pavement resting on an elastic soil foundation using finite element software. It has been found that, for smaller panel sizes with low radius of relative stiffness, critical stresses obtained are higher. Therefore, it is necessary to consider the effect of the size of slab panel and radius of relative stiffness, while designing the concrete pavement.

Noise Monitoring Networks as Tools for Smart City Decision-Making

Noise Monitoring Networks (NMNs) have been implemented in many cities by town councils, allowing them to know, in real time, the environmental noise levels in the busiest streets by the continuous measurement of selected acoustic parameters throughout the year. NMNs are aimed at: 1) detecting areas of the city that breach guidelines for acoustic quality objectives; 2) obtaining noise data needed to develop and implement action plans; and 3) informing the public about the permissible acoustic pollution for different districts and times of day. The aim of this work was to analyse data from the NMN of the city of Huelva (Spain), in order to study the influence on the noise of re-asphalting the busiest streets. The street pavements improve LAeq, 24 h from 3 up to 8 dB(A), depending on the type of the route. These results could be used by council authorities in deciding when to undertake the re-asphalting of the streets of Huelva, and to select the type of asphalt that should be used.

PUBLICZNE PROTESTY ANTYABORCYJNE W ŚWIETLE ORZECZNICTWA SĄDÓW KANADYJSKICH

Public Pro-life Protests in Canadian Case Law Summary The article deals with the legal standards applied in public anti-abortion protests in Canada. On the basis of an examination of Canadian case law, the author argues that the restrictions on pro-life protests are disproportionate with respect to the objective of ensuring safe access to women’s reproductive rights. The Access to Abortion Services Act and court injunctions are preventing pro-lifers from demonstrating in the vicinity of abortion clinics in defence of the right to life of unborn children. The degree to which pro-lifers’ constitutional freedom of speech is being infringed is in breach of the principles of the liberal state. The right to express opposition to abortion is also limited, although to a lesser extent, in other public places, such as street pavements and squares, university campuses and airport terminals. In the author’s view, imprisonment as the penalty for peaceful protest against the Canadian abortion law – for example, Linda Gibbons spent a total of over 10 years in prison for her pro-life activities! – is inherently incompatible with the essence of a “free and democratic society” as defined in Article 1 of the Canadian Charter of Rights and Freedoms.

Sustainable geotourism using digital technologies along a rural georoute in Monsagro (Salamanca, Spain)

ABSTRACTRural geotourism looks at the natural resources of the territory as a means of promoting a specialized, educational, sustainable tourism. This is an increasingly sought-after activity. This paper presents a rural georoute across a high mountain village, highlighting the remarkable value of the geological heritage of biological trace fossils and physical sedimentary structures exposed on street pavements and façades of houses. A series of tourist georesources were created and implemented: educational and interpretive panels, videos, QR codes, geoapps and games, all of which promote and disseminate the exceptional geological content and the history of the earth through the use of new technologies (smartphones, ipod, etc.). All this is intended as a means to make geotourism a natural tourism, favoring experiences, whilst explaining the natural environment and its temporal and spatial dimensions, offering opportunities for socio-economic development and job creation in rural areas with problems of depopulation.

A MODIS/ASTER Airborne Simulator (MASTER) Imagery for Urban Heat Island Research

Thermal imagery is widely used to quantify land surface temperatures to monitor the spatial extent and thermal intensity of the urban heat island (UHI) effect. Previous research has applied Landsat images, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images, Moderate Resolution Imaging Spectroradiometer (MODIS) images, and other coarse- to medium-resolution remotely sensed imagery to estimate surface temperature. These data are frequently correlated with vegetation, impervious surfaces, and temperature to quantify the drivers of the UHI effect. Because of the coarse- to medium-resolution of the thermal imagery, researchers are unable to correlate these temperature data with the more generally available high-resolution land cover classification, which are derived from high-resolution multispectral imagery. The development of advanced thermal sensors with very high-resolution thermal imagery such as the MODIS/ASTER airborne simulator (MASTER) has investigators quantifying the relationship between detailed land cover and land surface temperature. While this is an obvious next step, the published literature, i.e., the MASTER data, are often used to discriminate burned areas, assess fire severity, and classify urban land cover. Considerably less attention is given to use MASTER data in the UHI research. We demonstrate here that MASTER data in combination with high-resolution multispectral data has made it possible to monitor and model the relationship between temperature and detailed land cover such as building rooftops, residential street pavements, and parcel-based landscaping. Here, we report on data sources to conduct this type of UHI research and endeavor to intrigue researchers and scientists such that high-resolution airborne thermal imagery is used to further explore the UHI effect.