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Abstract

Permeable asphalt pavement (PAP) has many advantages such as reducing surface runoff and improving driving safety on rainy days; hence, it has attracted much attention from researchers. PAP is greatly affected by environmental factors due to its porous structure and the temperature characteristics are different from those of dense asphalt pavement (DAP). This study aims to understand the influences of environmental conditions on the patterns of temperature distribution in PAP and DAP. Weather station and temperature sensors were installed while paving PAP and DAP. Meteorological data and temperature data of each structural layer of PAP and DAP were collected during 2019–2021. The results demonstrate that temperatures in the depth range of 4 ∼ 10 cm below the PAP surface were 1 ∼ 6℃ higher than DAP on rainless days. The heat storage and dissipation efficiency of PAP within the depth range of 4 ∼ 40 cm were better than that of DAP. The maximum influence depth of PAP that heavy rainfall can affect is 60 cm, the maximum cooling extent of PAP is 5 ∼ 6℃, and the minimum cooling duration of PAP is 10 h on rainy days. This study provides a reliable foundation for evaluating the extent of the environmental impacts of PAP.

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... dosage of this material. However, porous asphalt concrete has been more and more used in pavement materials with the advancements in pavement green technology [15,16]. Therefore, modified asphalt with high viscosity is commonly applied in porous asphalt concrete [17,18]. ...
... Equation (13) describes the transformation between the primary curves of the G′ (ω) and the G (t). Then, Equation (14) was adopted to fit the master curve of the G (t). Finally, G (60 s) and mr (60 s) were counted according to Equations (15) and (16), respectively. (13) where, G (t) is the relaxation modulus (Pa), G′ (ω) is the storage modulus (Pa), t is the test time (s), ω is the angular frequency (rad/s). ...
... G (60 s) = ax 2 + bx + c | x=1.78 (15) m r (60 s) = 2ax + b | x=1.78 (16) Using −15 °C as the reference temperature, the master curve of the relaxation modulus of eight kinds of asphalt is drawn in this study ( Figure 12). Next, G (60 s) and mr (60 s) were counted (Figures 13 and 14). ...
Article
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To investigate the effect of styrene-butadiene-styrene (SBS) modifier content on the viscoelastic behavior of SBS-modified asphalt (SBSMA) at different temperatures and phase structures, the star SBS modifier was chosen to fabricate seven types of SBSMA with different contents. Multiple stress creep recovery (MSCR), linear amplitude sweep (LAS), and low-temperature frequency sweep tests were adopted to study the influence of SBS modifier content on the viscoelastic performance of SBSMA at high to low temperatures. The SBSMA’s microstructure with different contents was investigated using a fluorescence microscope. The results indicated that the change in non-recoverable creep compliance and creep recovery rate was bounded by 4.5% content at high temperatures, with an apparent turning point. The changing slope of content at less than 4.5% was much higher than that of the content greater than 4.5%. At medium temperatures, the fatigue life of SBSMA increased exponentially with the rising modifier content. The rate of increase in fatigue life was the largest as the content increased from 4.5% to 6.0%. At low temperatures, the low-temperature viscoelastic property index G (60 s) of SBSMA decreased logarithmically as the modifier content increased. In terms of the microscopic phase structure, the SBS modifier gradually changed from the dispersed to the continuous phase state with the increasing SBS modifier content.
... Therefore, the development of permeable pavement that allows rainwater infiltration is garnering significant research attention in the field of road engineering (Chu and Fwa, 2019;Dai et al., 2021;Wu et al., 2021). Research shows that permeable pavement can lower the pavement temperature during rainwater infiltration and evaporation, and rainwater purified by pavement structural layers can supplement groundwater, reduce surface run-off, and reduce pollutants (Jiang et al., 2015;Lu et al., 2022;Rashid et al., 2012;Yu et al., 2021). It can be seen that the migration characteristics of rainwater in permeable pavement have a significant impact on the temperature distribution of the functional characteristics of the permeable pavement (Chen et al., 2022;Li et al., 2022;Liu et al., 2020). ...
Article
To analyse the moisture migration characteristics of permeable asphalt pavement (PAP) in engineering applications , a PAP sample with a length and width of 163 m and 12 m, respectively, was designed and paved. The pavement comprised PAC-13, PAC-20, ATPB-25, graded grade, and sandy soil subgrade from the top to the bottom. Moisture sensors were set at 4 cm, 10 cm, 28 cm, 46 cm, 61 cm, 76 cm, 101 cm, 126 cm, 176 cm, and 226 cm below the pavement surface to ascertain the volumetric water content during and after rainfall. This data were used to analyse the changes in the infiltration depth, infiltration rate, water level height, and water emptying time of the PAP under different rainfall conditions. The results show that the prediction model for the infiltration depth can be established using the water adhesion rate and rainfall. According to the moisture changes of the pavement layer after rainfall, the water migration process of the PAP can be divided into the drying stage, wetting stage, emptying stage, and recovery drying stage. The relationship between the average rainfall intensity and the average infiltration rate is a linear function. The water emptying time at the depth of 0-10 cm is less than 20 h, and the emptying time at a depth below 10 cm is less than 6 d.
... Road designers can determine the high-temperature stability performance and low-temperature crack resistance performance requirements of asphalt pavement according to different environmental parameters, make the selected pavement materials and structural parameters meet the design requirements. Moreover, Researchers can more easily analyze the mechanism of pavement diseases [9][10][11], and predict the temperature field of pavement structure according to the change of environmental conditions [12]. These are helpful in predicting the possible quality problems and diseases of the road structure and provide reference for the daily maintenance and quality safety assessment of the road. ...
... To monitor the strain conditions of the pavement structure and pavement materials under actual loading, sensors and sensing devices are very important. Several special peculiarities are necessary for pavement sensors to deal with the harsh condition of pavement, such as high-temperature resistance, compaction resistance and corrosion resistance, etc. Literature reported the sensors using for pavement structure monitoring, including fiber Bragg grating sensor (FBG) [12], strain gauge sensor [13], temperature sensor [14], pressure sensor [15], humidity sensor and so on. ...
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Long-term and real-time monitoring of asphalt pavement can be carried out by using embedded sensors to perceive and predict structural damage during pavement operation period, so as to avoid sustained development of damage. However, the influence of embedded sensors on the mechanical properties of asphalt pavement structure and the structural optimization of sensing elements needs to be further studied. Based on the finite element numerical simulation method, static load model and three-point bending test mode were conducted with three “pavement-sensor” coupling model without sensor, with embedded I-shape sensor, with embedded corrugated-shape sensor. Three simulated conditions were studied comparatively of the sensing element embedding effect on the mechanical response of asphalt pavement structure. Results show that the sensing elements embedded with the two structures have a certain influence on the stress and strain field of asphalt concrete. Within the range of 60–100 mm the asphalt mixture is in a state of tension; the stress values increase with depth and show a maximum tensile stress state at the bottom of the beam. In the compression zone, the strain of the I-shape sensing element embedded is closer to that of the strain without the sensing element embedded. Along the axis of the two sensing elements, the axial strain of the I-shape sensing element is smoother and uniform, which ensures the deformation coordination in the road state. The optimal length L of the sensing element is 14 cm, the diameter φ of the sensor is 10 mm, and the I-beam length GL is 10 cm.
Article
As the world becomes more urbanized, concerns are growing about the phenomenon of urban heat islands (UHIs). In addition to the environmental function of stormwater management, pervious concrete (PC) pavements are also a solution that can help mitigate increasing urban temperatures, through cooling by evaporation. Several studies in the literature have focused on the evaporative cooling effect of PC, which requires the presence of water either from precipitation or irrigation. However, in countries that have dry summers and where watering techniques are complicated to implement, in hot weather and dry conditions, PC can have a higher temperature than traditional impermeable concrete. The main objective of this paper is therefore to study the influence of thermophysical parameters on the surface temperature of PC, with a view to designing a mix that minimizes its surface temperature in dry conditions. The thermal behavior of PC and ordinary impermeable concrete (OC) in dry condition have been studied both analytically and experimentally. All heat fluxes involved in the energy balance at the surface of both pavements were analyzed. The results show that PC has a surface temperature up to 6 ◦C higher than OC during the day and up to 4 ◦C lower during the night. Increasing the thermal conductivity of the pervious concrete makes the surface temperature of PC lower during the day but higher at night. On the other hand, increasing albedo makes the surface temperature of the pavement lower both during the day and during the night. Finally, the sensitivity study shows that the albedo has a greater influence on the maximum surface temperature of the PC than does thermal conductivity. To decrease the maximum temperature of PC, it is recommended to avoid the use of lightweight aggregates and to use finer and lighter colored aggregates (to increase the albedo), having high thermal conductivity. This mix optimization may be limited by the hydraulic properties of the PC due to its influence on the open porosity.
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The main contributing factor of the urban heat island (UHI) effect is caused by daytime heating. Traditional pavements in cities aggravate the UHI effect due to their heat storage and volumetric heat capacity. In order to alleviate UHI, this study aims to understand the heating and dissipating process of different types of permeable road pavements. The Ke Da Road in Pingtung County of Taiwan has a permeable pavement materials experiment zone with two different section configurations which were named as section I and section II for semi-permeable pavement and fully permeable pavement, respectively. The temperature sensors were installed during construction at the depths of the surface course (0 cm and 5 cm), base course (30 cm and 55 cm) and subgrade (70 cm) to monitor the temperature variations in the permeable road pavements. Hourly temperature and weather station data in January and June 2017 were collected for analysis. Based on these collected data, heat storage and dissipation efficiencies with respect to depth have been modelled by using multi regression for the two studied pavement types. It is found that the fully permeable pavement has higher heat storage and heat dissipation efficiencies than semi-permeable pavement in winter and summer monitoring period. By observing the regressed model, it is found that the slope of the model lines are almost flat after the depth of 30 cm. Thus, from the view point of UHI, one can conclude that the reasonable design depth of permeable road pavement could be 30 cm.
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The Taipei University of Technology, under contract from the Taipei City Government, completed a study on porous asphalt (PA) and permeable interlocking concrete brick (PICB) pavement performance with respect to stormwater runoff reduction and surface temperature mitigation. Additionally, the variation of infiltration rates against time of these pavements was monitored. The results show the following: (a) Runoff peak reduction ranged from 16% for large, intense storms to 55% for small, long-duration storms. Rainfall volume reduction ranged from 16% to 77% with an average of 37.6%; (b) Infiltration rate: for PICB, it decreased by 25% to 50% over a 15-month monitoring period, but the rate at one location increased significantly after cleaning; for PA, the rate remained high at one location, but decreased by 70%–80% after 10 months at two other locations, due mainly to clogging problems; (c) Surface temperature: during storm events, porous concrete bricks had on average lower temperatures compared to regular concrete with a maximum difference of 6.6 °C; for porous asphalt the maximum drop was 3.9 °C. During dry days, both PA and PICB showed a tendency of faster temperature increase as the air temperature rose, but also faster temperature decreases as the air cooled when compared to regular pavements. On very hot days, much lower surface temperatures were observed for porous pavements (for PA: 17.0 °C and for PICB: 14.3 °C) than those for regular pavements. The results suggest that large-scale applications of porous pavements could help mitigate urban heat island impacts.
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Permeable pavements are effective in mitigating the urban heat island effect via evaporative cooling and have been widely used in south China. However, few studies focus on the impact of evaporative cooling of different permeable paving materials on the outdoor thermal environment. In this study, two widely used permeable paving materials, sintered ceramic porous brick (CB) and open-graded permeable concrete (PC) were investigated. First, partial immersion tests were performed to characterize the water absorption properties of these materials. The results indicated that CB had a higher water absorption rate and a larger water retaining capacity than PC. Then, field measurements were conducted to evaluate the evaporative cooling performance of these materials. The results indicated that (1) water absorption capacity has an important impact on the evaporative cooling effect of permeable materials, a high upward capillary force could maintain the hydraulic continuity over a long distance, thus effectively prolongs the first stage of evaporation, (2) sprinkling water could reduce the surface temperature of both CB and PC by up to 10 °C and lower the ratio of sensible heat flux to the net shortwave radiation of CB and PC to 13.12% and 29.62%, respectively, (3) compared to non-sprinkling conditions, the maximum air temperature above CB and PC could be decreased by up to 1 °C. Additionally, CB could lower the black globe temperature and wet-bulb globe temperature (WBGT) of 0.5 m by up to 3 °C and 2 °C after sprinkling, respectively, suggesting that sprinkling water can improve thermal comfort above pavements.
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Full-text available
In this paper, one traditional asphalt and three permeable pavements were constructed to evaluate the thermal characteristics of pavement temperature at different depths and heat output in the field. The data were collected from May to July, 2011 to analyze with six traditional Chinese summer solar terms. On July 23, 2011 or Ta-Shu (great heat), it was the hottest day among six summer solar terms, while peak temperature of asphalt pavements was more than 60°C and ambient temperature was 36°C occurring at 14:00. In addition, it was found that reflectivity was affected by the color of pavement materials, and the thermal conductivity was influenced by the structural characteristics of pavements. The average heat output of grass bricks was found the least in comparison with others. Some heat outputs of porous asphalt concrete were larger than that of dense-graded asphalt concrete, especially from 16:00 to 21:00, but mostly were lower after midnight.
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Full-text available
Many pavements contribute to the urban heat island (UHI) effect due to their bulk mass and heat absorption capacities. Granular ground surfaces composed of soils or sands do not contribute to the UHI effect in a similar manner. Their porous nature may lessen the effect both with an increased insulating capacity and with an enhanced mechanism for evaporative cooling from absorbed water. Pervious concrete is a novel pavement which is being developed to aid in preventing stormwater related environmental problems. Pervious concrete has a network of interconnected voids which allow water exfiltration to the subbase below. Limited studies on pervious concrete indicate that the pervious concrete surface can have elevated temperatures as compared to similar traditional impervious pavements, but that temperatures are lower under the pavements. This study focuses on a site in Iowa where both a pervious concrete and a traditional concrete paving system have been installed and temperatures recorded within the systems for extended time periods. The analyses cover days with negligible antecedent precipitation and high air temperatures, extreme conditions for UHI impacts. This paper compares the increase in overall heat stored during several diurnal heating cycles in both of these systems. These analyses include not only the temperatures at various depths, but also the heat stored based on the bulk mass of the various layers in each system and below grade. Results suggest that pervious concrete pavement systems store less energy than traditional systems and can help mitigate the urban heat island. (246 words)
Article
For sustainable urban development, the permeable pavement aggressively attracts interests to promote urban water management. This study compared the infiltration and bearing capacities of different permeable pavement structures. To this end, artificial rainfalls with five different intensities were performed on four full-size pavement structures. The infiltration capacity of permeable pavements was estimated based on the runoff curves derived from in-situ measurement. Moreover, their clogging resistance capacity and recovery capacity after maintenance were featured respectively. The Finite Element Method (FEM) was conducted to compare the bearing capacity of four investigated pavement structures. The laboratory results demonstrated the permeability of asphalt mixtures was highly dependent on the water head difference. With regard to the field investigation, it was found that a thicker pavement structure enlarged the infiltration distance, as a result, extending the runoff rising moment and decreasing moment. Besides, a thicker pavement structure can effectively decrease the maximum runoff flow. Furthermore, a reasonable air void combination of multi layers is critical to achieve the optimal permeable performance of the pavement. Multi-layer structure pavement showed superior resistance to the clogging and recovery capacity under maintenance due to the existence of a clogging buffer area.
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Porous ultra-thin asphalt overlay (PUAO) is widely used in maintenance and new road surface layers. Since the paving thickness of PUAO is only about 20 mm, it is necessary to study its own performance and the overall performance of the double-layer material formed by the ultra-thin overlay and the under-layer mixture. PUAO and PUAO/asphalt concrete double-layer specimens with different air voids were prepared and the performance of the specimens were studied. The results showed that as the air voids increased from 15.8% to 24.4%, the PUAO’s high-temperature rutting dynamic stability decreased, the tensile strength ratio first decreased and then increased and the acoustic absorption coefficient peak value increased gradually, but the peak value of frequency moved from 400 Hz to 1250 Hz. The dynamic stability and low-temperature bending strength of the PUAO/AC-13 double-layer specimens were higher than those of the PUAO single-layer specimens. However, the double-layer specimen had a smaller permeability coefficient than the single-layer specimen. The International Friction Index showed that after 600,000 abrasion cycles, the F60 values of the five PUAOs were higher than those of the DUAO, indicating that the PUAO material had excellent skid resistance performance.
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With the rapid expansion of urbanization around the world, the urban heat island effect embraced an enormous negative impact on megacities, including energy, environment and health conditions. Unfortunately, construc-tive geometry and human activities of megacities severely intensified the urban heat island phenomenon. Giving the contributions of pavement on the deterioration of urban heat island in megacities, this literature review synthesized the state-of-the-art potential strategies of pavement cooling technologies and applications to mitigate the urban heat island effect. Firstly, the optical-thermal balance on surface and the interior thermal behavior of pavement were comprehensively analyzed. Afterwards, this paper redefined the cool pavement technologies as the passive mitigation strategies, involved the application of reflective pavement, evaporation pavement, heat- induced pavement and phase change materials. Especially, urban canyon impact and urban design were emphasized, which tended to be neglected on the implementations of cool pavement. In addition, the solar collector technologies on the pavement were proposed to sustainably reuse solar energy, acting as active stra-tegies and renewable sources. Typically, representatives of solar collectors, including heat collection and ther-moelectric pavement, were described and investigated. Existing research results presented the promising potential of pavement cooling technologies to mitigate the urban heat island impact and renewable energy sustainability. Moreover, prospects were also summarized to show the opportunities and avenues for future study.
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Porous asphalt (PA) is a distinct mixture type that deliberately designed with stone-on-stone contact of the coarse aggregate fraction and high percentage of interconnected air voids to provide water drainage and adequate resistance to both raveling and permanent deformation. During the past decades, PA has attracted much attention in the worldwide. Many studies have been conducted to confirm numerous benefits in terms of safety, comfort and environment. However, the acceptance of PA appears to have some sort of diminished when defects with durability and winter maintenance became a serious practical issue and overtaken by environmental concerns in recent years. Now this dilemma seems to be partially improved, several limitations have gradually ameliorated due to the progress of materials and test methods. While some additional problems are also exposed in the meantime. Therefore, it is necessary to present a comprehensive review of existing research to clarify the challenges that currently being encountered. The content of this article mainly includes international experience and four important aspects of PA mixture design, as well as the favorable contributing factors affecting each design process. In different sections, achievements including the advantages and shortcomings in each branch have been discussed and suggestions also have been put forward expecting to identify corresponding areas of study for future improvement, thus provide references for the next phase of field application of PA pavement.
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The purpose of this review is to give an up to date overview of the existing literature in fluid transport processes within Permeable Pavement Systems with the main focus on evaporation. The paper summarises the internal and external factors influencing evaporation rates in Permeable Pavement Systems, such as characteristics of the pavement surface and sub-surface layers, presence of water barrier/treatment systems, the water availability near the surface and ambient conditions. Experimental methodologies and designs used to investigate evaporation in laboratory and field settings are discussed, as well as limitations and constraints identifying existing gaps with the potential for further research.
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Porous asphalt pavements have been widely used because of their advantages of drainage and noise reduction. However, these pavements are susceptible to moisture damage due to the characteristically large portion of air voids. Therefore, the maintenance of porous asphalt pavement has become one of the research hotspots. Microwave technology is generally used as a kind of high-efficiency maintenance method, but now it is also recommended as the technology to heal the micro-cracks in the pavement. However, there is little research conducted on its healing efficiency of asphalt mixture suffered from moisture damage. In this paper, the influence of ferrite content on the pavement performance, mechanical properties and heating effect was studied. Through the indirect tensile fatigue test, the effects of microwave heating time, healing time and damage degree on the self-healing efficiency of moisture-damaged asphalt mixture before and after microwave heating were studied based on the evaluation indexes of the fatigue life extension ratio and fatigue life recovery ratio. It is found that the optimal microwave heating time and optimal healing opportunity of OGFC-13 asphalt mixture with 5% ferrite are 120 s and 50% damage degree respectively. In addition, the longer the healing time, the better the healing effect, but the influence of the healing time is smaller compared with the heating time.
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Permeable pavements are part of stormwater management practices known as sustainable urban drainage systems (SUDS). This study describes the influence of several environmental variables, such as the rainfall regime or the pollution build-up level, on the hydraulic and water quality performance of permeable pavements. Four infiltrometers with different configurations of pavement layers were used to study the influence of two rainfall regimes (Atlantic and Mediterranean) and two rainfall intensities (0.5 and 2.2 mm/min). The influence of the progressive pollution build-up level was studied by dry sprinkling of road deposited sediments collected with a mechanical street sweeper with a dose of 5 g/m²/d. The results show that permeable pavements retained a significant rainwater volume and improved the infiltrated water quality in terms of suspended solids, organic matter and nutrients when compared to the corresponding surface runoff potentially generated from an impervious pavement. The volume of rainwater retained inside them varied between 16 and 66% depending on the variables studied. The water infiltrated from permeable pavements subjected to a Mediterranean rainfall regime contained, in general, higher concentrations of organic matter (22 to 89 mg Chemical Oxygen Demand/l) and nutrients (0.6 to 2.1 mg Total Nitrogen/l and 0.05 to 0.45 mg Total Phosphorus/l) than those under Atlantic regime. However, the latter infiltrated higher loadings in terms of mass. Nitrogen was the substance that infiltrated the most, reaching a 25% of the total mass of nitrogen deposited on the pavements surface. The concentration and mass loading in infiltrated water increased as the pollution build-up level did. The leachability of nutrients and organic matter was greater for high rainfall intensities. The results suggest that it is essential to carry out an adequate cleaning in dry conditions, especially when high intensity rainfall events are foreseen, because of its greater capacity to mobilize pollutants.
Article
Numerical simulation is a powerful tool for assessing the causes of an Urban Heat Island (UHI) effect or quantifying the impact of mitigation solutions on local climatic conditions. However, the numerical cost associated with such a tool is quite significant at the scale of an entire district. Today, the main challenge consists of achieving both a proper representation of the physical phenomena and a critical reduction in the numerical costs of running simulations. This paper presents a combined parametric urban soil model that accurately reproduces thermal heat flux exchanges between the soil and the urban environment with a reduced computational time. For this purpose, the use of a combination of two reduced-order methods is proposed herein: the Proper Orthogonal Decomposition method, and the Proper Generalized Decomposition method. The developed model is applied to two case studies in order to establish a practical evaluation: an open area independent of the influences of the surrounding surface, and a theoretical urban scene with two canyon streets. The error due to the model reduction remains below 0.2 °C on the mean surface temperature for a reduced computational cost of 80%. Compared to in situ measurements the error remains bellow 1.24 °C at the surface.
Conference Paper
Fully permeable pavements capture stormwater and infiltrate it into the ground and/or hold it until discharging into stormwater conveyance. In either case, they offer benefits in terms of reducing or eliminating the need for stormwater conveyance infrastructure, capturing pollutants, and potentially reducing air temperatures around them. This paper reviews recent advances in structural design, materials and hydraulic design that have filled many of the gaps in permeable pavement technology. The paper then presents the results of a recent survey in California, with some additional out of state responders, regarding awareness of permeable pavements and obstacles to their implementation. Finally, the paper presents recommendations for filling remaining gaps and overcoming obstacles to implementation.
Article
This paper presents the results for the solar reflectance and temperature of 20 types of pavements used in Brazil for roads, parking lots, squares and sidewalks. New and aged pavement samples were tested. Some asphalt mixtures and Portland concrete mixtures were developed in the laboratory, with the addition of colored pigments in different percentages. The standard method ASTM E1918 and the procedure E1918A were used to measure solar reflectance of the pavements in the field. The difference between the surface reflectance values for surfaces with a lighter (white Portuguese mosaic) and darker (Reference CPA asphalt mixture) appearance was approximately 48%, and the corresponding difference in the measure surface temperature was 18.4 °C. A correlation between the solar reflectance and the temperature measured in the field is reported. The results obtained can be used as a reference to design public spaces, contributing to reducing the urban heat island (UHI) and improving the thermal comfort of the users.
Article
Heat can be transferred quickly and effectively through the convection associated with fluid flow. The heat convection coefficients of asphalt pavement with different porosities and surface temperatures are calculated using the characteristic size and the equivalent particle diameter of porous asphalt. A thermal model is built with the finite element software ANSYS to analyze the temperature reduction performance of porous asphalt pavement with heat convection considered. It can be seen from the results that the temperature reduction performance of road surface is positively linearly correlated with the asphalt porosity. In the hot season, the temperature reduction performance of porous asphalt pavement is better than that of dense asphalt pavement. Comparing with long-term indoor and outdoor measured data, reliability analysis using the statistical software SPSS reveals a similarity coefficient of 0.98 for the calculation results.
Conference Paper
Many pavements contribute to the urban heat island (UHI) effect due to their bulk mass and heat absorption capacities. Granular ground surfaces composed of soils or sands do not contribute to the UHI effect in a similar manner. Their porous nature may lessen the effect both with an increased insulating capacity and with an enhanced mechanism for evaporative cooling from absorbed water. Pervious concrete is a novel pavement which is being developed to aid in preventing stormwater related environmental problems. Pervious concrete has a network of interconnected voids which allow water exfiltration to the subbase below. Limited studies on pervious concrete indicate that the pervious concrete surface can have elevated temperatures as compared to similar traditional impervious pavements, but that temperatures are lower under the pavements. This study focuses on a site in Iowa where both a pervious concrete and a traditional concrete paving system have been installed and temperatures recorded within the systems for extended time periods. The analyses cover days with negligible antecedent precipitation and high air temperatures, extreme conditions for UHI impacts. This paper compares the increase in overall heat stored during several diurnal heating cycles in both of these systems. These analyses include not only the temperatures at various depths, but also the heat stored based on the bulk mass of the various layers in each system and below grade. Results suggest that pervious concrete pavement systems store less energy than traditional systems and can help mitigate the urban heat island. (246 words)
Article
In this study, self-developed laboratory apparatus was devised to investigate filtration effects of permeable asphalt pavements (PAP) and their mechanisms. The filtration effect of PAP is specified by measuring 16 pollutant indices in influent and effluent samples. Results show that the PAP is highly effective in removing copper (Cu), zinc (Zn), lead (Pb) and cadmium (Cd), and relatively less effective on petroleum pollutants (PP), animal & vegetable oil (AVO), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and ammonia nitrogen (NH4-N). The effect on removing total phosphorus (TP), chloride (Cl-) and total nitrogen (TN) is marginal. Influences of sampling time on pollutant concentrations were investigated as well, which indicates that the increases of sampling time reduce the pollutant concentrations to some extent. The decreases of pollution concentrations can be attributed to the interception and physisorption of porous materials used in the PAP.
Article
Increased nighttime temperatures caused by retained heat in urban areas is a phenomenon known as the urban heat island (UHI) effect. Urbanization requires an increase in pavement surface area, which contributes to UHI as a result of unfavorable heat retention properties. In recent years, alternative pavement designs have become more common in an attempt to mitigate the environmental impacts of urbanization. Specifically, porous pavements are gaining popularity in the paving industry because of their attractive storm water mitigation and friction properties. However, little information regarding the thermal behavior of these materials is available. This paper explores the extent to which porous asphalt pavement influences pavement temperatures and investigates the impact on UHI by considering the diurnal temperature cycle. A one-dimensional pavement temperature model developed at Arizona State University was used to model surface temperatures of porous asphalt, traditional dense-graded asphalt, and portland cement concrete pavements. Scenarios included variations in pavement thickness, structure, and albedo. Thermal conductivity testing was performed on porous asphalt mixtures to obtain values for current and future analysis. In general, porous asphalt exhibited higher daytime surface temperatures than the other pavements because of the reduced thermal energy transfer from the surface to subsurface layers. However, porous asphalt showed the lowest nighttime temperatures compared with other materials with a similar or higher albedo. This trend can be attributed to the unique insulating properties of this material, which result from a high air void content. As anticipated, the outcome of this study indicated that pavement impact on UHI is a complex problem and that important interactions between influencing factors such as pavement thickness, structure, material type, and albedo must be considered.
Article
The compaction of asphalt mixture at a proper temperature range is a very important factor to get the desired density of the asphalt mixture. The aim of this study was to determine the time at which the desired temperature is achieved and to investigate the effect of the permeable friction course (PFC) asphalt mixture properties on thermal conductivity. The thermal conductivity was measured using a surface probe type, and the values of thermal conductivity of PFC mixtures were smaller compared to dense-graded mixture. The relationships between thermal conductivity and asphalt mixture properties were investigated. Compaction temperature profiles were predicted using a simulation program that is developed based on one-dimensional (1D) heat conduction equation, finite difference method and environmental conditions. The results of the predicted temperature profiles were evaluated by comparing the measured in situ temperature profiles during compaction. From the results, it was found that the predicted time at a specified temperature could be used to determine the compaction time.
Article
Studies [1,2,11,13] have revealed that two major factors controlling urban air temperature excess over that of surrounding rural areas are the high heating rate of paved surfaces and anthropogenic heat released from domestic use, transportation and industry. Therefore, in this study, heating effects of the ground surface on the thermal environment are investigated for the purpose of understanding the mechanisms, and if possible, controlling the thermal behaviour of the pavement or wall materials in the urban area.
Temperature Variation of Porous Asphalt Pavement under Hangzhou Climate Circumstances [J]
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Temperature reduction performance of porous asphalt pavement considering heat convection
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  • Y.-Y Cheng
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Y.-Y. Cheng, S.-L. Lo, C.-C. Ho, J.-Y. Lin, S.L. Yu, Field testing of porous pavement performance on runoff and temperature control in Taipei City, Water 11 (12) (2019) 2635.
Temperature Variation of Porous Asphalt Pavement under Hangzhou Climate Circumstances
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T.-Y. Ni, Y. Yang, D.-Y. Kong, C.-C. Ma, C. Fang, Temperature Variation of Porous Asphalt Pavement under Hangzhou Climate Circumstances [J], Urban Environ. Urban Ecology 1 (2009).
Retrofitted fully permeable shoulders as a stormwater management strategy on highways, Asphalt Pavements
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  • J Harvey
D. Jones, H. Li, J. Harvey, Retrofitted fully permeable shoulders as a stormwater management strategy on highways, Asphalt Pavements, CRC Press, 2014, pp. 769-778.