Pavement Surface Temperature Research Articles

Study on Temperature Related Factors of Asphalt Pavement Based on APRIORI

Asphalt is a typical temperature-sensitive material. In order to explore the correlation between surface temperature of asphalt pavements and meteorological factors, the association rules mining algorithm (Apriori) was applied to identify the key factors affecting the surface temperature of asphalt pavement. Firstly, errors and missing data in the meteorological dataset were cleaned. Then, Apriori was applied to identify the key factors affecting the asphalt pavement temperature. The results indicate that Apriori would perform an excellent ability to analyze the correlation rules between meteorological factors with the minimum confidence of 0.8 and the key meteorological factors which affect the temperature change of asphalt pavements are excavated including air temperature, air pressure, dew point temperature and relative humidity. The research would serve as a technical support for the machine learning algorithms applied in the field of the association rule analysis.

Modification of AC Thermal Properties to Mitigate UHI Effects

Abstract An analysis of the asphalt concrete (AC) pavement material properties that affect surface temperatures is presented. These properties affect the contribution to the urban heat island effects. Its goal is to analyze the effect of various alternative aggregate materials, such as limestone, silica, polymer, glass, and graphite, on AC pavement surface temperatures under various environmental conditions. Pavement surface temperatures were analyzed for two extreme weather locations in the United States, namely South Texas and Northern Minnesota. Long-Term Pavement Performance weather data over a year-long period were analyzed for each location using the computer model Temperature Estimate Model for Pavement Structures. The average and range of pavement temperatures were compared at a depth of 0.01 m. It was concluded that the higher the coefficient of thermal conductivity, heat capacity, and albedo of the pavement surface layer, the lower the average and maximum surface temperatures are during the summer months. Graphite was shown as a promising limestone aggregate substitute producing significant reductions in AC surface temperatures. It reduced the peak daily surface temperatures by between 3.5°C and 5°C. On the other hand, the modified AC mixtures showed mechanical properties not quite at par with those of conventional ACs.

Research of Deicing and Melting Snow on Airport Asphalt Pavement by Carbon Fiber Heating Wire

In the paper, the method of deicing and melting snow by the carbon fiber heating wire (CFHW) embedded in the airport asphalt pavement is proposed to improve the security of airport operation. The field experiment of deicing and melting snow on the airport asphalt pavement is conducted. Deicing and melting snow, asphalt pavement temperature, ice‐free area ratio, and snow‐free area ratio are analyzed. Electrical power with 350 W/m2 is input to the airport asphalt pavement for deicing and melting snow by the CFHW. In the experiment, 3 mm ice can be melted, and the average infrared ray temperature (IRT) of the airport asphalt pavement surface can achieve an increment of 13.0°C in 2.5 hours when the air temperature is from −7.5°C to −2.2°C. Snow with 3.2 mm precipitation can be melted in 2 hours when the air temperature is from −4.8°C to −3.5°C, and the asphalt pavement temperature can achieve an increment of 5.9°C at the depth of 0.5 cm. The results show that the method of deicing and melting snow on the airport asphalt pavement by the CFHW is practicable in the cold zone.

Experimental investigation into the thermal augmentation of pigmented asphalt

Asphalt binder is a temperature dependent material and is more susceptible to damage at higher temperatures. During summers, low thermal conduction and high specific heat of conventional asphalt results in extreme pavement surface temperatures and increased vulnerability. The situation demands for use of additives/modifiers that could help reduce pavement surface temperature. Thermal conduction of pigment modified/non-black asphalt mixtures is investigated in this research. Study focuses both on heating and cooling phase w.r.t time. Asphalt mixtures were evaluated for thermal conduction using larger heat sink with internal dimensions of 100×100×50 mm3. However, bituminous mixtures were examined in smaller heat sink with internal dimensions of 60×60×25 mm3. Both heat sinks were subjected to 800, 1000, and 1200 W/m2 heat flux and measurements were recorded accordingly. DC power supply was used as a heating source and silicon heater as a heating surface. Sinks were connected with data logger via calibrated K-type thermocouples. Iron oxide red and Titanium dioxide white pigments are used to decolour the black mixes. 4% by weight of total mix of each pigment is used to colour the black binder. Results have shown that at the end of 3 h of heating phase, pigment modified samples remain 8–10 °C cooler in case of bitumen binder and 4–5 °C cooler in case of asphalt mixtures. At the end of 2 h of cooling phase, a difference of 3–4 °C was noted between pigmented and conventional asphalt. Results also show that pigmented mixtures not only conduct more heat but also cool faster. Quantitatively, pigmented mixtures conduct 10%–15% more heat in comparison to the unmodified/black asphalt mixtures. The reduction in temperature susceptibility of pigmented mixtures may also help improve their high temperature performance.

Heating process monitoring and evaluation of hot in-place recycling of asphalt pavement using infrared thermal imaging

The original asphalt pavement heating plays a key role in the entire construction procedure of hot in-place recycling (HIR). At present, the temperature of heating process in HIR is monitored by infrared temperature gun with single or multiple test points which cannot fully understand real heating situation. Moreover, there are no evaluation indices for quantifying heating quality. To objectively perceive and evaluate the heating quality, the infrared thermal imaging (ITI) system was used to monitor heating process of HIR and the combination of digital image processing (DIP) and artificial neural network (ANN) was applied to extract and correct the distorted thermal image to restore pavement surface temperature. Based on corrected thermal images, the heating quality of HIR was firstly quantitatively evaluated using three proposed indices: transverse uniformity Tu for evaluating the temperature uniformity, represent temperature RT for assessing the heating effect and proportion of temperature above 200 °C PTA200 for judging the overheating. Furthermore, on-site heating quality of three heating systems: respectively flame, infrared radiation and recycled hot-wind system, was analyzed and compared based on the above three indices. The results indicate that the superiority of the flame system and the infrared heating system is strong heating effect to realize the higher pavement surface temperature, but the temperature uniformity is poor, even some areas are overheated. On the contrary, the recycled hot-wind heating system provides the better temperature uniformity and avoids overheating, but the heating effect is poor. In addition, a comprehensive analysis reveals that high RT and poor Tu are mainly cause of overheating and the better Tu is required to match the increasing pavement surface temperature for high level of the heating quality. Finally, when using 200 °C as the high temperature boundary, the evaluation indices Tu and RT preferably satisfy the following relationship RT + RT × Tu < 190 °C to avoid occurrence of overheating in HIR.

Asphalt pavement coated by hot-pressed hydrated lime

ABSTRACT Hot-pressed hydrated lime (HL) on the surface of asphalt pavements forms a type of light-coloured cool pavement, which is called hot-pressed HL pavement. In this cool pavement, unmodified HL at the millimetre particle size is commonly used. This study used HL with three particle sizes (1200, 600, and 200 mesh), modified by graft polymerisation and emulsion polymerisation. The cooling effect and laboratory performances (skid resistance, abrasion resistance, anti-glare performance, and erosion resistance) were evaluated. The effects of particle size and surface modification were evaluated, and the cost of this cool pavement type was analysed. Hot-pressed HL reduced the surface temperature of asphalt pavement by about 10°C. The decreased particle size of HL improved both the cooling effect and the erosion resistance. HL modification slightly decreased the cooling effect, but significantly enhanced abrasion resistance, anti-glare performance, and erosion resistance. A particle size of 1200 mesh, spreading dosage of 100 g/m2, and graft polymerisation modification are recommended for HL. Noteworthy, the cooling effect of hot-pressed HL pavements is slightly weaker than that of traditional heat-reflective coating pavements; however, the cost of the former material is only about 0.01 times of the latter.

Pavement Overlay Design using Falling Weight Deflectometer

Pavement evaluation is a technique of assessing the condition of a pavement, both structurally and surface characteristics. Pavements which have been subjected to traffic, deform elastically under load which depends on type subgrade soil and its compaction level, pavement thickness and its composition, drainage conditions, pavement surface temperature and wheel load. There are number of different types of pavement deflection testing equipment which are being used all over the world. The most common types are Benkelman Beam Deflection (BBD), Falling Weight Deflectometer (FWD) and Dynamic Cone Penetrometer. BBD test widely used method in which rebound deflection is measured on static loading and there by evaluating strength of the pavement. However with limitations and practical difficulties of BBD, FWD was chosen for the study. The deflections of the pavement are recorded due to the dynamic loading and studied for further strength determination. A 4-lane National Highway has been selected and tested for residual strength and it is designed for overlay as per IRC:115-2014 &amp; IRC:37-2012 using FWD equipment and with the assistance of KGPBACK and IIT PAVE software’s. An overlay of 50 mm on one direction and 100 mm on opposite direction was recommended to meet the functional and structural requirement respectively.

Skid resistance of gap graded hot-mix asphalt with added crumb rubber

Road surface condition is a critical factor that determines road safety. The paved surface of the road should have sufficient skid resistance to enable a vehicle passing over it to accelerate and stop/brake safely and comfortably. Gap graded hot-mix asphalt is generally used as a non-structural and an impermeable layer to protect the structural layers. The hot rolled sheet (HRS) asphalt mixture has larger cavities that require more asphalt compared to other asphalt pavement types. The addition of crumb rubber (CR) to the asphalt mixture was carried out using the dry mixture method, and the resulting mixture was added to the aggregate. This study utilizes gap graded asphalt pavements containing natural asphalt from a processed product called Asbuton Retona blend 55. CR was added to the asphalt mixture in proportions of 0.5%, 1%, 1.5%, and 2%. This added material improves the performance of the asphalt mixture. The skid resistance of the paved surface layer studied herein used the British pendulum tester for pavement surface temperature variations of 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, and 50 °C. Utilization of CR derived from used tire rubber powder provides the benefit of reusing waste materials that can help preserve the environment. The gap graded hot-mix asphalt with added CR and asphalt modified Asbuton Retona blend 55 has shown an improvement in the skid number. These results show that the hot-mix asphalt pavement with modified asphalt is more impermeable and provides better slip resistance.

Elaboration of an Analytical Formula for the Calculation of the Surface Temperature

Pavement structures are sometimes subject to repeated dimensional variations of thermal origin generating mechanical stresses that may be detrimental to their durability. Among the most frequently observed degradations, by these stress, are the transverse cracks whose frequency, depth, and variable openings reduce the ride comfort. In this context, where such solicitations are preponderant and the strong variation is noticed on the surface, an analytical approach for calculating the surface temperature of a flexible pavement has been proposed. This approach is able to deal with the transient thermal problem including the phenomenon of ambient temperature and the influx of solar flux specifically for arid regions where the sky is often clear. This approach is adopted because it proposes a simplified calculation of the surface temperature. The model was built on a database measured on the experimental pavement of the laboratory of Egletons GEMH (France), using the calculation code Eureqa formulate. Although neglected in the domain's literature, the meteorological parameters (air temperature and solar flux) are taken into consideration in the analytic function because they give good prediction. The model has practical meanings to predicting the maximum, minimum, and amplitude of the pavement surface temperature. Hence, a good surface temperature assessment provides a key factor for further thermal cracking modeling.

Developing anti-icing airfield runways using surface embedded heat wires and renewable energy

Airfield runway safety is significantly affected by winter snow, ice, and slush conditions. These wet wintry conditions impact aircraft control and stopping distances. Airport operators use deicing chemicals and plowing to maintain safe runways during wet wintry conditions. However, snow removal is costly. This article presents an alternative approach to applying deicing chemicals and plowing. The approach discusses using a heated pavement system (HPS) with surface embedded wire. Nichrome heating wire is embedded at the slab surface level and energized by an outside source to heat the pavement through Joule heating. Renewable energy generated through a photovoltaic system is used to energize the wires within the concrete slab. To reduce energy demand, the system is designed as an anti-icing system in contrast to a deicing system. Consequently, energy is continually supplied to the system to maintain an above freezing pavement surface temperature independent of ambient weather conditions.An anti-icing runway slab was developed by supplying DC energy from a photovoltaic energy system to experimental concrete slabs with surface embedded heat wire. Experiments were conducted supplying energy to test panels and analyzing pavement surface temperature changes. Energy usage is controlled in the proposed system using control relays. The control relays allow current flow to only surface embedded wires in pavement sections that require a pavement surface temperature increase. This article identifies the challenges and benefits of using surface embedded heat wires with a photovoltaic system to develop an anti-icing pavement system. The approach discussed in this article proposes methodology to develop an anti-icing airfield runway pavement system that relies on a sustainable energy source, solar energy, as it’s energy source. Solar energy is used to recharge a storage energy bank for energizing the proposed system.

Linearity between Pavement Thermophysical Properties and Surface Temperatures

AbstractTemperature of in-service pavements can be regulated by varying the thermophysical properties of the pavements. Although empirical correlation between the thermophysical properties and pave...

Study on thermal parameters of asphalt concrete for countermeasures against high surface temperature of pavement in tunnel

It is reported that the surface temperature of asphalt pavement in a road tunnel in an urban area in summer days gets hot especially when the tunnel is long and the traffic volume is heavy. Since the asphalt pavement absorbs a large amount of heat generated by vehicles and keeps it for a long time, a high-temperature environment in the tunnel also continues for a long time. This phenomenon brings uncomfortableness for users, especially for motor-bikers and maintenance workers. On this background, this study aims to estimate the thermal parameters of the various types of asphalt concrete and investigate their effects on a high-temperature pavement surface. Six types of asphalt concrete specimens were tested in a wind-tunnel where a hot temperature air inside was generated by a forced circulation boiler system. Thermal parameters: specific heat capacity, heat conductivity, heat diffusivity, and heat transfer coefficients were analysed using a one-dimensional partial differential heat transfer equation and a finite difference approximation method. Additionally, the effects of different basement boundary conditions and water spray on the surface temperature were investigated to find effective countermeasures to decrease the surface temperature of asphalt concrete in the tunnel.

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.

Experimental Study on Heat-Reflective Epoxy Coatings Containing Nano-TiO2 for Asphalt Pavement Resistance to High-Temperature Diseases and CO/HC Emissions

Abstract The experimental study and an optimized formulation heat-reflective coating has been studied with epoxy resin as the matrix resin and nano titanium dioxide (TiO2) as the functional filler for asphalt pavement to deal with high-temperature diseases and carbon monoxide (CO) and hydrocarbon (HC) emissions from automobile exhaust. The mass ratio of the epoxy resin: diluent: curing agent: nano-TiO2: and ferric oxide was determined to be 100: 24: 36: 6.4: 0.3. Under the irradiation of the tungsten–iodine lamp, the epoxy coatings can reduce the surface temperature of the asphalt pavement to 57.9°C, whereas the reference surface temperature reaches 71.3°C. The epoxy coatings exhibited excellent wear resistance after 3 h of testing on a rutting machine. Furthermore, the CO/HC decomposition effect on the epoxy coatings has also been investigated, with a maximum decomposition rate of 19.3 % at 50°C and an ultraviolet intensity of 2,770 μW/cm2. The epoxy coatings have been proven to be a good solution for high-temperature disease and excessive CO/HC emissions from asphalt pavements.

Determining asphalt surface temperature using weather parameters

Abstract Temperature affects the structural response of asphalt concrete (AC) pavement. To evaluate the performance, it is important to accurately predict the pavement surface temperature. This study develops three regression models to determine the surface temperature of an asphalt pavement using field measured data such as air temperature, wind speed, wind direction, relative humidity, and solar radiation. Three models namely, 24-h model, day-time model and night-time model were developed based on one-year continuous data. The weather data were measured from October 2012 to October 2013 at an instrumented pavement section on Interstate I-40 near Albuquerque, New Mexico. The developed regression models were validated using October 2014 to June 2015 weather data, which were not used in developing the regression models. Surface temperatures predicted using the developed regression models were then compared to those predicted using the pavement mechanistic-empirical (ME) software's default model. It is observed that the regression models are better predictors of pavement surface temperatures than the ME default models. A parametric study was also performed in this study to identify the effects of weather parameters on the pavement surface temperature prediction. The authors of this study expect that this study will be useful in pavement design especially in cold regions.

A novel solar reflective coating with functional gradient multilayer structure for cooling asphalt pavements

Abstract Solar reflective coating is an effective way to reduce the surface and internal temperature of asphalt pavements. Existing coating is limited by its single-layer structure, and its development has persistent challenges, highlighting a need to study novel coating with high cooling efficiency, safety and durability. In this paper, a solar reflective coating with functional gradient multilayer structure was designed, named FGMC. It consisted of three different functional layers arranged in a gradient from top to bottom, including a near-infrared transmission layer, a strong reflection layer and an insulating bonding layer. The key pigments or fillers used in each layer were determined by utilizing an indoor irradiation test. The optimal dosage of pigment G, pigment Y, titanium dioxide and floating beads was 3.7%, 3.7%, 15.2% and 16%, respectively. The cooling effect of the proposed coating was investigated by comparing the surface and internal temperature of the coated and uncoated asphalt mixture specimens. Results showed that the strong reflection layer contributed the most to cooling effect, reducing temperature about 8.5 °C–9.5 °C. The internal temperature of specimens coated with FGMC used pigment G and pigment Y decreased by 11.5 °C and 13 °C respectively. Moreover, the skid resistance, water resistance, alkali resistance and abrasive resistance of the proposed coating met the requirements of standards. The proposed coating can reduce temperature and provide a new direction for solar reflective coating of asphalt pavements.

Design, construction, and evaluation of energy-harvesting asphalt pavement systems

Energy-harvesting pavements, one of which is the Hydronic Asphalt Pavement (HAP) system, have been proven to be both more durable and sustainable than conventional pavement systems. A HAP consists of a system of connected pipes embedded within the asphalt pavement which function to extract or reject heat from/into the pavement via a circulating fluid. Three large-scale systems were designed and constructed in the field: a control section, a regular HAP section, and a section containing a HAP coupled to a horizontal ground heat exchanger (GCHAP). The field data showed that neither the HAP section nor the GCHAP section were able to substantially decrease the pavement surface temperature. However, both GCHAP and HAP were able to decrease the asphalt temperature at a depth of 2.5 cm below the surface by a magnitude of around 10°C. Another key finding of this study shows that increasing the conductivity of a flexible pavement asphalt layer, rather than increasing the conductivity of the embedded pipes, significantly enhances the effectiveness of the HAP system.

Development of automated electrical heat grid for pavement snowmelt

Snow and ice on airfield pavement threatens aircraft ground operation safety. Plowing and chemical treatment are used for snow removal, but yield long-term detrimental impacts to the airfield infrastructure and environment. In this paper, a “near-surface embedded electrical heating grid prototype” is investigated through laboratory and field testing for concrete pavement heating, providing an airfield pavement anti-icing alternative. The prototype grid, installed on small-scale concrete test mats, was studied in a laboratory controlled below-freezing temperature environment. Testing evaluated pavement surface heating performance under two energy supply methods: (1) an alternating heating sequence and (2) an automated thermostat heating sequence, assessing their ability to (1) raise the pavement surface temperature to an anti-icing temperature threshold, 2 °C, and (2) sustain an anti-icing surface temperature. The alternating heating sequence required a low power input, but an increased heating time. Under the automated thermostat heating sequence, with a 152.4 mm parallel heat wire spacing and 667 W/m2 power input, surface temperature rose from an initial −12 °C to 2 °C in 4 h, then maintained in the anti-icing range, 2 °C to 5 °C. Laboratory, preliminary study results directed the construction, instrumentation, and operation of a large-scale prototype slab for field testing. The prototype was built in Fayetteville, AR and subjected to ambient outdoor climate conditions. The full-scale testing used a photovoltaic energy system as the power source. Field testing assessed heating/anti-icing performance and energy consumption. During tests in below freezing air temperatures and snow events, the photovoltaic energy system supplied enough energy to maintain the large-scale prototype slab surface above 0 °C.

Thermal performance of waste materials as aggregate replacement in asphalt pavement

The high surface temperature of the conventional asphalt pavement due to high solar energy absorption could contribute to the Urban Heat Island (UHI) phenomenon. Concurrent with this phenomenon, rapid urbanization and industrial development have led to a large quantity of waste products available for disposal or recycling. Therefore, this study investigates the thermal performance of selected waste materials that could potentially be used as aggregate in asphalt pavement to combat the problem of increased pavement surface temperature. A number of waste materials were selected for the thermal performance measurement and compared to granite as conventional aggregate. The cylindrical and slab samples of AC14 dense graded asphalt were prepared for the different selected aggregate types. The samples were then measured for solar reflectance using Spectroradiometer. In addition, the surface and internal temperature profiles of the samples were monitored using infrared camera and thermocouples, respectively, in exposed environments. Based on the results, it is possible to use some of the waste materials as an aggregate replacement in order to reduce the UHI impact.

Evaluation of a Novel Road Thermoelectric Generator System

Capturing the unused energy is the challenging aspect in the harvesting process. Since one potentially important component for energy harvesting in the transportation sector is pavement, successful energy harvesting from roadway pavements can lead to sustainable transportation infrastructure systems. Asphalt pavement surface temperature can reach up to 70˚C in summer because of solar radiation. This paper presents a development of novel set of road thermoelectric generator system and describes the operation, design, and performance of the system installed within pavement that captures the heat energy from the temperature differential between the pavement surface and the subgrade soil. Designed prototype encompasses of thermoelectric generator, coolant module, heat collector and conductor. The efficiency and performance of the designed system were evaluated through the experiments and finite element modeling. Based on the results, the generated electrical power from the asphalt pavement could be a key source for providing off-grid power supply for sensors used in smart infrastructure, structural health monitoring, and environment sensing.