Asphalt Solar Collector Research Articles

A State-of-the-Art Review of Hydronic Asphalt Solar Collector Technology for Solar Energy Harvesting on Road Pavement

Nature inspires innovative renewable energy solutions by advancing our road pavements, as the sun is the only infinite and accessible source of clean and green energy on our planet. In addition to the various solar energy production methods, a new paradigm for utilizing asphalt pavement as a solar collector is being developed for self-powered energy harvesting. Due to direct solar radiation, flexible paved surfaces exposed to direct sunlight can heat up to 70°C in the summer. The heat is then dissipated into the environment, causing the urban heat island effect, and accelerating thermal oxidation of asphalt pavement. This can lead to structural failure and reduced pavement performance. This study aims to present a state-of-the-art review of hydronic asphalt solar collectors (HASCs) and propose the best model to enhance the performance of asphalt solar collectors. The findings of the study concluded that asphalt has the potential to absorb solar energy and store heat energy. This can be achieved by assembling and modifying conventional asphalt structures into modern asphalt solar collector designs that consist of pipe arrangements below the paved surface filled with liquid flowing through the pavement surface. The study found that a significant limitation of previous research was that it focused on optimizing the temperature profile at various depths but did not focus on structural improvements to reduce failure and increase the performance of asphalt solar collectors. Therefore, this review study proposed a new technique of using conductive and waste materials to enhance the performance of asphalt solar collectors.

Experimental and numerical analysis of an asphalt solar collector with a conductive asphalt mixture

Asphalt solar collectors (ASCs) have emerged as a promising renewable energy source. They offer a practical solution for generating renewable energy and thereby reduce the reliance on fossil fuels. In this study, a computational analysis and experimental validation of an ASC with a conductive asphalt mixture were conducted. The ASC that was investigated had 3000 mm long serpentine copper tubes positioned at the center of a 1000 mm ×60 mm ×8 mm sample of hot-mix asphalt. Ten 250 W infrared bulbs installed in two rows served as the simulated heat source of the ASC. The ASC had a water flow in the range of 14–97 L⁄h and solar intensities of 600, 800, and 1000W/m2. The thermal response of the ASC was modeled using the COMSOL Multiphysics 5.6.0.280 heat-transfer module. The experimental results indicted that the efficiency of the ASC was 53.56% or 64.1% with either reference or conductive mixtures, respectively. When a conductive mixture was used in the ASC, its surface temperature decreased by 11.37% when compared to that obtained using the reference mixture. The numerical simulation revealed that the average deviation between the numerical and experimental temperature data of the water that flowed within the ASC tubes was between 6% and 14%. The use of conductive asphalt mix would enhance the thermal performance of ASCs.

A review of design parameters, advancement, challenges, and mathematical modeling of asphalt solar collectors

A review of design parameters, advancement, challenges, and mathematical modeling of asphalt solar collectors

Thermal response of an asphalt solar collector: Numerical and experimental validation

This study conducts a numerical analysis and experimental validation of the thermal performance of an asphalt solar collector. Both parallel and serpentine copper tubes with a total length of 3000 mm were embedded in the middle of a 1000 × 600 × 80 mm hot mix asphalt model. The sides and bottom of the test sections were insulated to prevent heat loss to the surrounding environment. Using four values of water mass flow rate and three values of artificial solar radiation, the thermal performance of the system was examined. A mass flow inlet of 0.0038–0.035 kg/s is specified for the water inside the embedded tubes, while 600, 800, and 1000 W/m2 solar radiation is applied on the upper section of the asphalt mix during this study. The thermal response was simulated using the COMSOL Multiphysics 5.6.0.280 heat transfer module. Using a reference asphalt solar collector, the desired parameter effects were investigated independently. The experimental results showed that the efficiencies of the asphalt solar collector with serpentine bare tubes and parallel bare tubes are 53.56 % and 52.85 %, respectively. The numerical simulation reveals that there is no significant thermal effect in the area under the embedded tubes when compared to the area above the tubes that are exposed to solar radiation from above. The average error found between the numerical and experimental results for the water temperature difference inside the embedded tubes of the asphalt solar collector ranged between 6 % and 14 %. This good agreement indicated that the computational fluid dynamics model is reliable and capable of simulating the thermal response of an asphalt solar collector.

THE THERMAL CONDUCTIVITY ENHANCEMENT OF ASPHALT SOLAR COLLECTOR: LITERATURE REVIEW

This comprehensive review article presents an in-depth examination of the augmentation of thermal conductivity in asphalt solar collectors, emphasizing the importance of modified asphalt mixtures and their influence on the efficiency and longevity of solar pavements. The manuscript elaborates on the implications of thermal conductivity for the physical, mechanical, and thermal attributes of asphalt, and investigates various methodologies for modifying asphalt mixtures, such as the integration of thermoplastic elastomers, crumb rubber, polymers, poly-phosphoric acid, and nanomaterials. Moreover, the review accentuates techniques for amplifying thermal conductivity, encompassing the incorporation of metallic particles, carbon nanotubes, graphene, graphite, and phase change materials. Subsequently, the article delineates distinct approaches for assessing thermal conductivity in modified asphalt, comprising steady-state and transient methodologies, and underscores the necessity of selecting a suitable technique based on project specifications and limitations.This review shall add to local knowledge an important engaged in the advancement of effective and sustainable asphalt solar collectors.

Thermal performance of asphalt solar collector by improving tube and slab characteristics

Thermal performance of asphalt solar collector by improving tube and slab characteristics

Rutting Behavior of Asphalt Surface Layers Designed for Solar Harvesting Systems

Solar harvesting systems applied to asphalt roads consist of pipes or coils installed a few centimeters below the asphalt pavement surface. They work thanks to a circulating fluid able to collect the heat coming from solar irradiation of the pavement surface and convert it into thermal gradients that can be used for electric energy supply. Specific attention must be paid to the design of the asphalt mixtures comprising the system. In this sense, the high in-service temperature rutting potential is one of the main issues to be assessed in such applications since the thermal optimization of asphalt mixes could lead to excessively deformable materials. The present study is a part of a wider research area aimed at developing an efficient asphalt solar collector. Here, a laboratory mixture-scale investigation is proposed to verify the anti-rutting potential of specific asphalt layers that were initially designed based on thermal properties only. Repeated load axial and wheel tracking tests are carried out on limestone- and steel slag-based bituminous mixtures. Overall, the tested layers were not fully able to satisfy the permanent deformation acceptance criteria; in this regard, possible improvements in terms of mix constituents and properties are ultimately addressed.

Enhancing the thermal conductivity of hot-mix asphalt

Conductive hot-mix asphalt is recommended for enhancing the solar energy collection performance of an asphalt solar collector. This type of collector consists of embedded tubes with circulating water or air inside pavement construction to generate power. This work intends to shed light on the selection of novel components for the preparation of conductive asphalt mixes. Lee's disc method was used to determine the thermal conductivity of this composite material. A comprehensive examination was conducted to prepare reference and conductive asphalt discs by manufacturing asphalt mixtures in a laboratory specified for this work. New Iraqian natural resource materials, including quartzite sandstones and silica sands, and Iraqian industrial waste materials, such as slag stones, steel wool fibres and metallic waste powder, were employed as conductive components. The results showed that the conductive materials increase the thermal conductivity of the reference asphalt mixture up to 42.75% and 66.65% for quartzite and slag combinations, respectively. Slag aggregates should not be utilized as conductive material in asphalt mixes without increasing the binder ratio. Proportions of 4% and 38% of steel wool fibres and metallic waste powder additives, respectively, were found to produce the optimal results for thermal conductivity enhancement. The air void contents and fracturing ratio of conductive discs were decreased when using conductive novel components, which is an indication of the importance of current findings in improving asphalt mixtures in heat storage and transfer applications.

Thermal Performance Enhancement of Asphalt Solar Collector by Using Extended Surfaces

The Urban Heat Island (UHI) effect occurs when the temperature of the asphalt pavement surface exceeds 70°C during the summer. Rutting is a significant temperature-related problem that occurs when the temperature rises too high on asphalt surfaces. Additionally, this phenomenon increases the amount of energy required to cool buildings adjacent to pavements and degrades air quality. The Asphalt Solar Collector (ASC) was examined in this work by inserting tubes into the pavement's construction and circulating working fluid within it to capture thermal energy generated by asphalt pavement. A low-carbon steel-alloy cheap waste materials have been investigated as an extended surface with HMA. The effect of various extended surfaces attached to the embedded tubes on the thermal performance of ASC has been studied to determine whether it satisfies specified aforementioned demands. The performance of several ASC models with bare, continuous finned, and mesh grid serpentine embedded tubes was investigated with same Conductive Hot Mixture Asphalt (C-HMA) by using a numerical 3-D model developed by COMSOL Multiphysics Software. when the Reynolds Number is increased, it is found that ASC efficiency increases from 66.74% for bare serpentine tubes to approximately 75.488% and 69.4% for continuous finned and mesh grid serpentine embedded tubes, respectively. A maximum value of about 398.53 W can be gained (from a total of 850 W/m2 incident solar radiation) by utilizing an extended surface. Additionally, the surface temperature of HMA decreases significantly from 52.67 to 46.07℃. For all models under investigation, it is clear that the optimum average Reynolds Number is about 600. It is found that the continuous fins model can capture more solar radiation than the mesh grid model by about 8.77%.

Pavement energy harvesting technologies: a critical review

The world energy consumption is constantly increasing and the research point towards novel energy harvesting technologies. In the field of pavement engineering, the exploitable sources are the solar radiation and the vehicle load. At present, these systems are able to convert the sunlight into electricity thanks to some solar cells placed under a semi-transparent layer (photovoltaic roads), or they can harvest thermal heat by means of solar thermal systems. The thermal gradient of the pavement can be exploited by thermoelectric generators, by heat pipes or by heat-transfer fluids (i.e. water) pumped into a medium (asphalt solar collectors, porous layer or air conduits). The traffic load can be exploited by piezoelectric materials, able to convert the vehicle load into an electrical charge.
 The aim of this paper is to describe the main pavement energy harvesting technologies, pointing out positives and negatives and providing indications for further optimizations. Finally, the systems are compared in terms of initial cost, electrical output, efficiency and technology readiness level.

Inducing directional heat transfer by enhancing directional thermal conductivity of asphalt mixtures for improving asphalt solar collectors

Low thermal conductivity makes heat conduction in asphalt pavements quite slow, restricting asphalt solar collectors. To enhance the directional thermal conductivity of asphalt mixtures and induce directional heat transfer, directional heat-induced channels are built in asphalt mixtures by using carbon fibers with high axial thermal conductivity. A finite element method is used to simulate and study the temperature field and heat flow distribution of asphalt mixtures. A parametric analysis of the carbon fiber parameters is performed to evaluate the variation in the performance of the effective thermal conductivity of asphalt mixtures. The temperature trend of asphalt mixtures is measured by an indoor irradiation experiment and compared with the simulation results. The results show that heat-induced channels have obvious heat convergence effects and can induce heat to be efficiently conducted along its axial direction. These channels can significantly improve the directional thermal conductivity of asphalt mixtures and are expected to play a heat transfer bridge between the pavement surface and the energy collection system when using them in asphalt solar collectors in the future.

Investigation on performance of an asphalt solar collector: CFD analysis, experimental validation and neural network modeling

This paper presents a numerical model, development, and experimental validation of an Asphalt Solar Collector (ASC) which subsequently is modeled by Artificial Neural Network (ANN). In this research, 2 m long galvanized pipes are connected in parallel and embedded into an asphalt slab with 1 m2 area. The slab is buried in the ground to have thermal heat transfer with adjacent soil and to resemble real conditions. Several experiments are carried out in both warm and cold months of the year with different water flow rates from 9:00 to 17:00. The ASC is modeled with CFD techniques and the desired parameters effect are independently studied based on a reference condition. An ANN model is proposed to expand the parametric study and reduce the high computational cost of numerical modeling. The inputs of the ANN include the design and the operating parameters and the outlet water temperature is considered as the output. These models are capable of evaluating the performance of the ASC at every hour during the day and under different boundary conditions. The parametric study shows that improvement of surface absorptivity and thermal conductivity of asphalt leads to a higher increase of the daily efficiency in August, however, the inlet water temperature has the same effect in November. The maximum water temperature difference and the thermal efficiency of the ASC can reach up to 24 °C and 45% in August and 14 °C and 35% in November respectively.

Thermophysical properties and heating performance of self-healing asphalt mixture with fibres and its application as a solar collector

This paper presents the first analysis on the evaluation of the thermophysical and heating performance of self-healing asphalt mixtures with different contents of steel wool fibres for their potential use as a solar radiation absorbing material in an asphalt solar collector prototype. With this aim, four different dense-graded asphalt mixtures were prepared using the same aggregate gradation and bitumen content, but with different content of steel wool fibres: 0%, 2%, 4%, and 6% by total volume of bitumen. Physical and thermal properties, such as bulk density, air void content, thermal conductivity, specific heat capacity, and thermal diffusivity were evaluated on the asphalt test specimens. Steel wool fibre distribution inside the asphalt mixture samples was also evaluated by X-ray computed microtomography. Moreover, the thermal behaviour of a solar collector prototype, using an asphalt mixture with 4% of steel wool fibres as a solar radiation absorbing material was exposed to solar radiation conditions simulated in laboratory using a novel direct normal irradiance experimental model. This model was developed by the authors to experimentally simulate the maximum and minimum irradiance conditions for the city of Concepcion in Chile. The main results showed that self-healing asphalt mixtures with steel wool fibre addition reduced their thermophysical properties, explained by an increment in their total volume and due to the fibre distribution inside the samples. Additionally, this study proves that asphalt mixtures with 4% of steel wool fibres can be potentially used as a radiation absorbing material, transmitting the infrared radiation from the asphalt pavement surface to the water stored inside it. In short, this study provides the first assessment on the fundamental thermophysical variables of self-healing asphalt mixtures with metallic fibres, with the purpose of exploring their future use for energy harvesting applications.

Study on effect of glazing on performance and heat dynamics of asphalt solar collectors: An experimental study

Exposure to solar irradiation for an extended period during a day causes asphalt pavements can reach to a considerable temperature. Consequently, they can be converted into an affordable solar collector by harvesting thermal energy. In recent years much effort and time have been devoted to improving the thermal performance of solar collectors. To this aim, the glazing strategy is a promising technique. The glass covers results in the reduction of heat loss and protecting the asphalt surface (absorber surface) from the outside environment. Little attention has been given to the glazing strategy in improving the performance of ASCs. The chief aim of the current investigation is a comparative assessment of the performance and heat dynamics of unglazed asphalt solar collectors with glazed asphalt solar collectors under field conditions. The evaluation was carried out using an experimental test-setup composed of an asphalt solar collector with a surface area of 1.2 m2 and a pipe network length of 12 m. Various sensors were utilized to monitor and measure the key parameters such as ambient conditions and working fluid temperature during the experimental runs. The experimental results prove that the glazing strategy is an effective method to improve the performance of ASCs. The constructed glazed ASC increases hot water temperature, meanly around 5 °C, and pavement temperature, meanly around 20 °C, while represents an improvement in the performance, near 10%, compared with the unglazed one.

Effectiveness of Continuous and Discontinuous-Flow Strategies in Heat Dynamics and Performance of Asphalt Solar Collector: An Experimental Study

Asphalt solar collectors (ASCs) offer a low-cost and reliable alternative to harvest energy from available infrastructures such as roads and pathways by employing the simple techniques. This paper represents an experimental study to evaluate the effectiveness of continuous and discontinuous-flow strategies in the dynamics and performance of a self-constructed ASC under field conditions. To this aim, an ON/OFF switching controller commands to run and stop the system at different time intervals. During the experimental simulations, all the crucial environmental and operational parameters were measured and monitored. This approach assesses the effects of numerous scenarios with different intervals of time on the dynamics of the constructed collector. Continuous and discontinuous-flow strategies were evaluated by comparing three different scenarios, including continuous-flow mode, 5 min OFF-mode and, 10 min OFF-mode. The results show that by extending the OFF-mode, the water is kept stagnant in the hot embedded pipes for more extended periods. Therefore, the temperature difference at the inlet and outlet of collector reduces, and the water leaves the collector at higher temperatures; however, the efficiency of the ASC decreases. Also, even though extending the OFF-mode results in heated water exits the collector at higher temperatures, but the mass of heated water decreases due to continuous interruption of current flow. The test results prove that in continuous-flow strategy, cumulative heat gain improves. Therefore, the continuous-flow strategy shows higher performance than introduced discontinuous-flow strategy. The exergy analysis illustrates that the available useful exergy has significantly affected by considering the pump consumed energy.

Editorial

Nanofluids are gaining attention in the exchange, conversion, and storage of energy, owing to their enhanced thermophysical characteristics. Since the thermal conductivity of metals are far higher than that of fluids such as water and oil, adding metal nanoparticles into such fluids can result in a new medium with improved heat transfer properties. Apart from pure metals, nanoparticles made of metal-oxides, silicon carbide, composites, bio-based materials, etc. are also used for this purpose. Nanofluids are produced by engineered-dispersion of nanoparticles in a base fluid, which significantly enhances the thermal conductivity of conventional heat transfer fluids (Ganji et al. 2018; Sheikholeslami 2019). However, the thermophysical characteristics of nanofluids depend on the size, shape, and volumetric fraction of the dispersed nanoparticles. An interesting breakthrough in nanofluids is the advent of hybrid nanofluids wherein two or more nanoparticles are immersed in the base fluid, which has shown further enhancement of the thermal and rheological properties (Kumar and Arasu 2018). Nanofluids play important role in energy exchange and conversion applications (Jama et al. 2016;Nagarajan et al. 2014; Said et al. 2014; Reddy et al. 2017; Hussain et al. 2019; Muñoz-Sánchez et al. 2018; Bhalla and Tyagi 2017; Islam et al. 2015). Holkar et al. (2018) listed different nanofluids employed for energy harvesting and their advantages. Apart from these, cupric oxide nanofluid was proposed to improve the heat transfer performance of asphalt solar collectors that harvest solar energy from roads (Hashim 2014). The efficiency of direct absorption solar collectors could be improved by the use of nanofluids as the absorption medium (Nagarajan et al. 2014;Otanicar et al. 2010). A major challenge in the use of nanofluids for energy applications is the contradictory behavior of thermal conductivity and specific heat. While the enhancement of thermal conductivity of base-fluid by the dispersion of nanoparticles is well established, there are no consistent findings on the enhancement of specific heat capacity (SHC) (Lu and Huang 2013), which is a desirable property for energy storage. Several studies reported decline of SHC of aqueous nanofluids, whereas non-aqueous nanofluids showed improvement of SHC (Shin and Banerjee 2010). This issue has been tackled in many studies, and it remains an ongoing challenge. Adding nanoparticles to molten salts that are used as heat transfer fluids in concentrated solar power (CSP) system could enhance the thermophysical properties including SHC and enable the CSP plants operate at higher temperatures (Shin and Banerjee 2010; Lu and Huang 2013). Muñoz-Sánchez et al. (2018) provided a comprehensive review on the use of molten salt-based nanofluids for energy storage and transfer at higher temperatures. Owing to the growing environmental concerns on the conventional synthesis techniques of nanoparticles, the emerging trend is to adopt green synthesis approaches (Genuino et al. 2013; Ghulam 2016). The nanoparticles produced by green synthesis are termed as green nanoparticles, and the nanofluids prepared from them are known as green nanofluids (Narayanan and Rakesh 2019). Several researchers have reported development and characterization of green and eco-friendly nanofluids such as silver and gold nanofluids (Mollick et al. 2014)(John et al. 2015), grapheme-based nanofluids (Mehrali et al. 2016), and coconut fiber-based nanofluids (Adewumi et al. 2018). These green nanofluids would be promising alternatives for their conventional counterparts for various energy conversion applications.

The effect of the environmental parameters on the performance of asphalt solar collector

Abstract In this research, asphalt Solar Collector ASC was built outside the laboratory. Atmospheric air was used as a working fluid. The effect of the environmental conditions such as ambient temperature, wind speed, variation of solar day time, and ASC chimney height are considered. The construction of the ASC system consists of aluminum buried pipes under asphalt layers with the two ends open. In the present study for the construction of the used ASC and its thermal properties, experimental were carried to evaluate the effect of chimney height on the flow field. The results showed that the chimney height has a strong effect on the average air flow velocity through the ASC. Also, the ASC prototype performance for collecting the solar energy and transferring it to the flowing ambient air depends on the used chimney height, as well as the environmental/atmospheric conditions in terms of ambient air temperature, and wind speed.

Demonstrating Innovative Technologies for the Flemish Asphalt Sector in the CyPaTs Project

In 2015, the ROAD_IT project initiated the development and demonstration of an integrated and coherent IT process control system for the Flemish asphalt sector in order to modernize existing asphalt paving technologies and to obtain real-time data to monitor pavement behavior. One of the demonstration test tracks is CyPaTs, the construction of a bicycle path built in September 2017, using innovative technologies (www.uantwerpen.be/cypats). Five technologies are described in this contribution. An asphalt solar collector (PSC) with a piping system was installed directly in the asphalt. Cold water during summer season and hot water in winter season running through the pipes, keep the asphalt structure in a better temperature interval, avoiding rutting and cracking. Other advantages of this system are: energy gain, the prevention of damage to asphalt and the enhancement of traffic safety. The expected energy gain per year varies between 0.5 and 0.8 GJ/m2. About 20% of this energy is used for the operation of the asphalt collector itself. The remaining 80% can be used in nearby buildings. Fiber Bragg Grating (FBG) monitoring system was integrated in all three asphalt layers for the first time in Belgium. Two novel approaches of FBGs installation in asphalt layers were elaborated in this bicycle path: installation of FBGs in prefabricated asphalt specimens at the bottom of base layer and installation of FBGs in a saw cut of approx. 2mm in the previously constructed asphalt layer. The results proved a survival rate of the FBGs of 100%. The obtained strain and temperature data from FBG monitoring system has proved to be an excellent approach to establish and reflect the real condition of the asphalt pavement behaviour in time at different temperatures. The temperatures of the asphalt pavement during construction were followed up by the infrared thermography measurement techniques: a thermographic line-scanner (PAVE-IR by Moba AG) which was mounted at the back of the finisher and a hand-held IR camera (FLIR T640) was used for taking pictures every 2 meters. A real-time temperature contour plot of the pavement during construction was created to monitor asphalt pavement temperatures for quality inspection during the paving process or for later assessment. Two other non-destructive technologies for quality assessment were applied during this project. At first, the thickness was measured using aluminium plates and the MIT-SCAN T3. The obtained values were compared with topographic height measurements. Secondly, the density was measured with the PQI-380 non-nuclear density meter at several spots. The objective here is to check the density of the bicycle path, as well as the accuracy and investigate different parameters that influence the variations of the results, in particular the temperature dependency.

3D numerical modelling and experimental validation of an asphalt solar collector

Research about renewable technologies for thermal energy collection is crucial when critical problems such as climate change, global warming or environmental pollution are concerned. Transforming solar energy into thermal energy by means of asphalt solar collectors might help to reduce greenhouse gas emissions and fossil fuel consumption. In this paper, a laboratory-scale asphalt solar collector formed by different slabs has been characterized by applying numerical techniques. An experimental test where the thermal performance of the collector was determined for three values of heat exchange fluid flow rate was carried out for the validation of the numerical model. Then, the CFD model was used to analyse the thermal response of the collector according to the following parameters: flow rate, solar irradiance, size and thickness. Results show that increasing values of heat exchange fluid flow rate result in better thermal performances. Likewise, increasing values of irradiance and size of the collector lead to higher values of thermal performance, although other parameters should also be considered for the final design of the system. Finally, under the conditions here considered, the thickness of the collector turned out not to be as significant as expected in relation to its thermal response. The combination of experimental tests and CFD codes can be considered a powerful tool for the characterization of asphalt solar collectors without incurring significant costs related to experimental field tests.

Effect of freezing-thawing and ageing on thermal characteristics and mechanical properties of conductive asphalt concrete

Conductive asphalt concrete with graphite can improve the workability of asphalt solar collector (ASC), which provides an interesting method to mitigate a series of realistic problems related to asphalt pavement. The freezing-thawing cycles and ageing of asphalt material are recognized as critical factors that could affect the durability of asphalt pavement. In this paper, the influences of freezing-thawing and ageing on mechanical properties and thermal characteristics of conductive asphalt concrete (CAC) were experimentally investigated. Control asphalt concrete samples were prepared by the same aggregate gradation and volume composition with CAC. The thermal properties of asphalt concrete were studied by Thermal Constants Analyzer. Experimental results indicated that freezing-thawing effect would lead to volume expansion and strength degradation of CAC samples. During the freezing-thawing test, the thermal conductivity and specific heat of CAC tend to decrease while the thermal diffusivity increased correspondingly. Although ageing process would degrade the moisture resistance, low temperature and fatigue properties of conductive asphalt concrete, there was no significant differences in thermal conductivity, thermal diffusivity and specific heat between the original and aged samples. Compared to control asphalt concrete, the incorporation of graphite improved the anti-ageing properties of conductive asphalt concrete.