Road Materials Research Articles

Analysis of Thermal Characteristics of Urban Streets Using Thermal Imaging Camera : Case Study of Commercial Streets in Banjarbaru

Continuous urban growth and global warming over the past few decades have led to the urban heat island (UHI) effect, which has become a serious threat to urban residents. Impervious surfaces, low-albedo buildings, and lack of vegetated areas are the main causes of poor urban thermal environments, especially during summer. Several previous studies only focused on the thermal characteristics of each building unit that influence pedestrian thermal comfort. The aim of this research is to analyze the thermal characteristics of various physical elements on urban roads using thermal imaging cameras, and present a conceptual model of improved road shapes and materials for buildings and pavements with respect to the thermal environment in cities to improve the thermal comfort of outdoor pedestrians room. This study examines the road-scale thermal environment of two main commercial roads: A. Yani street km.33-37 and Panglima Batur street, in Banjarbaru, South Kalimantan. This study conducted field measurements both during the day and at night in July 2023 to investigate changes in urban surface temperatures over time. The results show that trees are the most effective mitigation element for reducing surface temperatures. With regard to the type of building use, the highest surface temperature is near asphalt shophouses with minimal trees along the road. Glass building facades and dark-colored or partially metal-covered walls contribute to high surface temperatures. Likewise, the temperature of cast concrete in parking areas and sidewalks on urban streets is also very high during the day. The thermal characteristics of various urban road elements should be considered to reduce surface temperatures and reduce the urban heat island effect.

Use of Coconut Coir Geotextiles, a Green Material for Sustainable Low-Volume Roads

Use of Coconut Coir Geotextiles, a Green Material for Sustainable Low-Volume Roads

Pemanfaatan Limbah Gypsum Sebagai Subtitusi Filler Dalam Campuran Aspal Panas Dengan Metode Perendaman Berulang

This research was made using gypsum waste which is expected to improve the quality of asphalt concrete to the characteristics and meet the technical requirements to be used as road pavement materials. This study aims to analyze the characteristics of hot mix asphalt (AC-WC) using oil asphalt with variations of gypsum waste in repeated immersion. This study uses an experimental method, namely an experiment to get results, thus it will be seen the utilization of gypsum waste in asphalt concrete construction with variations in gypsum waste levels of 10%, 15%, and 20%. The results showed that the use of gypsum waste will affect the characteristics of the asphalt mixture

Properties of recycled facemask fiber modified asphalt binder: Comparative analysis of surface modification and composite modification method

Polymer-modified asphalt binders had been developed as a novel strategy for road and building materials. People generally use disposable facemasks to reduce the risk of respiratory diseases during travel and commuting. These discarded masks will become a serious environmental problem. Recycled facemask has great potential application in the modified asphalt, but its modification effect of modified asphalt needs to be studied. In this work, different kinds of fibers and their modified asphalts had been successfully prepared and comparatively analyzed after the surface of fibers treated by butyl acrylate (BA) and further modified by copper oxalate (CO) nanoparticles. From the test results, the activation energies of polypropylene fiber extracted from recycled facemask (RPF) modified asphalt (RPA), treated RPF (MRP) modified asphalt (MRPA), and MRP further decorated with CO (MRPCO) modified asphalt (MRPCOA) were 64.08 kJ/mol, 59.09 kJ/mol, and 62.32 kJ/mol, respectively. MRP and MRPCO were better dispersed in asphalt than RPF. MRPA performed a lower value of the viscoelastic than RPFA, but MRPCOA performed the higher value of viscoelastic than MRPA. Compared with RPA, the short-term aging factors of MRPA and MRPCOA decreased by 31.73% and 53.18%, while long-term aging factors of MRPA and MRPCOA decreased by 11.34% and 12.31%. From the nanoindentation data, the maximum depth of MRPA increased by 5.23% and the hardness decreased by 2.55% than RPA. The maximum depth of MRPCOA also decreased by 6.68% and its hardness also decreased by 4.45% than MRPA. These results indicated composite modification of RPF performed better than only surface modification based on the viscoelastic and aging properties of modified asphalts. It provided a meaningful study for the potential applications of various recycled polymeric fibers in modified asphalt binder in the future.

Engineering properties on salt rock as subgrade filler in dry salt lake: Water retention characteristics and water migration patterns

As a special road material, salt rock has high strength and stability in arid areas, and has broad application prospects in highway engineering construction in dry salt lake areas. To investigate the water retention characteristics of salt rock and its water migration patterns under the covering effect, and to ensure the long-term durability of salt rock subgrade, this study presents a comprehensive analysis of the effect of initial dry density on the water retention characteristics of fine-grained salt rock fillers. The soil–water characteristic curve model of salt rock was recommended. The capillary water migration patterns of salt rock were proved. The water migration patterns of salt rock under freeze–thaw cycles were clarified. The hydrothermal state of salt rock subgrade under the influence of pavement overburden was evaluated based on the field monitoring. The results indicated that the water retention capacity of fine-grained salt rock filler increases with the decrease of initial dry density during the high suction stage. The Fredlund & Xing model is recommended to address the soil–water characteristic curve of fine-grained salt rock. The capillary action of salt rock filler decreases with increasing compaction. The temperature gradient from the upper boundary to the bottom of the soil column under the effect of freeze–thaw cycles is significant. After five freeze–thaw cycles, the water in the soil column continued to migrate upwards under the covering effect and temperature gradient. The relative humidity and temperature of the salt rock subgrade both show a sinusoidal cyclical variation. When the temperature range of salt rock subgrade is −6°C–30 °C, the relative humidity of subgrade is significantly correlated with temperature. This study can provide theoretical support for the disaster prevention and control of salt rock subgrade covering effect in the Lop Nor area.

Perspective contact imprint parameters of road roller working body with bearing surface when compacting road materials

Introduction. The most efficient machine for compacting road building materials in the construction of transport facilities, a road roller with a promising pneumatic tire roller that can effectively use vibration, is considered.Materials and methods. The results of the studies characterizing the parameters of the imprint of the contact of the working body of the roller with the supporting surface, which significantly affect the efficiency of the technological operation of compacting road materials, are presented. During the experiment, the values of the minor and major axes of the contact imprint ellipse, its area, the value of contact pressures depending on the load on the roller and the number of metal bands installed on the roller were revealed.Result. The article provides illustrations of the experiments carried out, the data obtained in the form of analytical and graphical dependencies are presented.Discussion and conclusion. The bandages on standard tires that are mass-produced are installed. The presented promising road roller, which combines the capabilities of different sizes (by weight) of rollers, which can speed up the process of compacting materials, reduce energy, metal and labour intensity and increase the efficiency of road construction.

IMPACT OF DEICING SALT ON THE PERFORMANCE OF ASPHALT MIXTURES IN NORTHWEST CHINA: AN INVESTIGATION INTO MECHANICAL PROPERTIES AND INFLUENTIAL FACTORS

Currently, the primary form of high-grade highways is constituted by asphalt concrete pavement. Winter conditions often result in ice and snow accumulation on these pavements, precipitating severe traffic incidents. Statistically, around 15%-30% of such incidents are directly linked to icy and snowy conditions. Hence, when roads are laden with ice and snow, the most cost-effective and efficient countermeasure remains the dispersal of deicing salt onto the road surface. Particularly in China's northwestern region, which experiences low precipitation and consistent droughts, the deicing salts applied during winter aren't diluted or transported away by water flow. Consequently, the soil surrounding the roads retains a higher concentration of deicing salts than other regions, leading to a pronounced impact on the pavement's service life. This investigation aims to experimentally emulate the impact of this high-salt environment on the mechanical properties of asphalt mixtures, followed by an analysis of the crucial factors that influence the asphalt mixtures' durability. The current study employs measures such as high-temperature rut testing, Marshall water immersion testing, and freeze-thaw splitting testing to investigate the damage patterns of mechanical properties in asphalt mixtures under varying grading, diverse deicing salt solutions, and differing frequencies of dry-wet cycles. In addition, the study employs grey correlation entropy analysis to ascertain the interdependence among factors influencing the performance of asphalt mixtures. The findings reveal that after undergoing 0, 5, 10, 15, 20, 25, and 30 dry-wet cycles in solutions of 20% industrial salt (NaCl), 15% urea (CH4N2O), and 20% anhydrous ethanol (CH2CH3OH), both the high-temperature stability and water stability of asphalt mixtures with AC-13 and AC-16 gradings displayed varying levels of decline. Overall, an enhancement in the fine aggregate percentage in asphalt mixtures can augment the asphalt concrete's resistance to deicing salt erosion. As per the grey correlation entropy analysis, gradation variances exerted the most significant impact on diverse mechanical properties, followed by the type of deicing salt solution, with the least significant impact attributed to the frequency of dry-wet cycles. Thus, judicious selection of road materials and structural design can effectively counter the erosive action of deicing salts, thereby enhancing the service life of the road surface.

Cement-stabilized large-sized steel slag base course based on vibration compaction method: Mechanical properties, shrinkage properties, and numerical simulation

The excellent mechanical properties and wear resistance of steel slag contribute to the properties of road engineering materials. The hot-stuffing aged slag was chosen as raw material for this study. Cement-stabilized large-sized steel slag (CSLS) mixtures containing different structural types, cement contents, and curing time were prepared by vibration compaction method. Afterward, the properties of CSLS mixtures such as unconfined compressive strength (UCS), indirect tensile strength (ITS), compressive resilience modulus (CRM), dry shrinkage and temperature shrinkage were investigated. Ultimately, the Mises stress and deflection value of CSLS road structure with different construction methods and construction seasons were explored by ABAQUS.

Analysis of the Synergistic Effect on the Strength Characteristics of Modified Red Mud-Based Stabilized Soil.

Based on the existing research results, this research team developed roadbed stabilized soil materials using nano-SiO2 synergistically modified red mud in order to study whether the strength of the stabilized soil materials meets the strength requirements of the roadbed materials, and at the same time, analyze its strength characteristics to make the feasibility of it being used as a roadbed material clear. Through different combination schemes, the effects of different nano-SiO2 and cement contents on the strength of the stabilized materials were explored. The test results show the following: In the synergistic modification of nano-SiO2 and cement, nano-SiO2 can significantly improve the early unconfined compressive strength of red mud-based stabilized soil. In the synergistic modification of nano-SiO2, gypsum, and cement, the 7 d unconfined compressive strength of red mud-based stabilized soil is greater than 2 MPa, which meets the strength requirements of road base materials and shows the superiority of synergism. The nominal stress-strain curves are divided into five stages: compressed and compacted stage, elastic deformation stage, plastic deformation stage, damage deformation stage, and residual deformation stage. The macroscopic compressive damage pattern of the specimens shows that the modified red mud-based stabilized soil mostly exhibits brittle damage. Tests have shown that the strength of modified terracotta-based stabilized soil meets the requirements of roadbed strength.

Experimental investigation of the response of guardrail posts embedded in road shoulder material under quasi-static and dynamic impact loading

The main functions of vehicle restraint systems (VRS) are to redirect errant vehicles and prevent them from entering an opposing lane or carriageway, as well as preventing them from colliding with structures along the road [1]. In the case of steel guardrail systems, fulfilment of these requirements greatly depends on the soil-post interaction, which influences the deformation and energy dissipations of the VRS during impact.To date, there is no unified method of modelling the behaviour of guardrail posts embedded in road shoulder material in crash tests simulations. For this reason, the influence of soil type and state as well as post characteristics on the observed motion of vehicle and VRS cannot be adequately evaluated, which is, however, necessary to improve and optimise a VRS without increasing the number of crash tests.This paper presents the findings of a series of static and dynamic full-scale loading tests conducted with different road shoulder materials and post types, the aim being to create an experimental database for modelling the soil-post interaction in crash test simulations. The novel dynamic and static testing techniques used ensures repeatability and enables the reliable evaluation and interpretation of the results.We found that not only the static and dynamic post response but also the failure mode are significantly influenced by the relative soil density and post embedment length. As long as there is no yielding of the post section, the dynamic post resistance varies with increasing impact energy until a maximum value, which depends on the dynamic horizontal bearing capacity of the post. Any further increase in impact energy has no influence on the post resistance.

Research on Water Stability and Crack Resistance of Waste Cellulose Acetate–Reinforced Asphalt Mixtures Based on Response-Surface Methodology

The objective of this study was to explore the engineering application potential of waste cigarette butts and to investigate the effect of waste cellulose acetate (WCA) as reinforcement material on the performance of asphalt mixtures. A performance prediction model was also constructed to explore the optimal mixture preparation scheme. In this study, a scanning electron microscope (SEM) was used to visually characterize the surface morphology of WCA. The elemental composition of the cellulose surface was determined semiquantitatively using an energy dispersive spectrometer (EDS). The experimental design was carried out following the face-centered central composite design (FCCD) of the response-surface methodology (RSM), taking WCA shearing time, WCA content, and asphalt-aggregate ratio as variable factors, and the splitting strength (Rdry), freeze–thaw splitting strength (Rsaturated), and tensile strength ratio (TSR) of the mixtures as response variables. The software Design-Expert was adopted to construct and optimize the model under multiple responses. The road performance was verified by rutting test, low-temperature bending test, and water immersion Marshall test. The results showed that WCA is a kind of organic cellulose with a smooth surface and cloverlike cross section, which can significantly improve the mixture’s crack resistance and water stability. The performance prediction models all achieved a fit of 90% or higher. The best parameters recommended by Design-Expert were WCA content of 0.201%, WCA shearing time of 11.847 min, and asphalt-aggregate ratio of 5.683%, and the WCA-reinforced asphalt mixture Rdry, Rsaturated, and TSR values were 1.38 MPa, 1.24 MPa, and 89.86%, respectively, all of which were within the 95% prediction interval of the model predicted values. In addition, the road performance tests showed that WCA significantly improved the mixture’s flexural strength and water stability, but harmed the high-temperature rutting resistance. WCA has a significant reinforcing effect on asphalt mixture, which has a certain reference value for recycling waste cigarette butts and developing green road materials. In addition, the FCCD model has high accuracy and can effectively guide the road material preparation process.

Experimental Study on the Curing Mechanism of Red Mud-Based Stabilized Soil Co-Modified by Nano-SiO2 and Gypsum.

In order to effectively utilize red mud and reduce its occupation of land resources, as well as its impact on the environment, experiments were conducted to develop stabilized soil materials using nano-SiO2 synergistically modified red mud and to investigate the curing mechanism of stabilized soil. The unconfined compressive strength, microscopic morphology, and curing mechanism of the red mud-based stabilized soil materials with different amounts of modified materials were investigated. The test results show that after 7 days of curing, the unconfined compressive strength of red mud-based stabilized soil meets the compressive strength requirement of road base material when nano-SiO2, gypsum, and cement are synergistically modified. In such cases, the soil structure has the lowest fracture rate and the best structural compactness when the amount of nano-SiO2 is 1%. It is found that the needle-like and columnar calcium alumina in the modified red mud-based stabilized soil increases, and the binding energy of hydration product ions in the modified material is improved. The chemical curing mechanism of modified red mud-based stabilized soil includes hydration reaction, pozzolanic reaction, promotion effect of nano-SiO2, and enhancement effect of gypsum. On this base, a model of the early start hydration process of red mud-based stabilized soil promoted by nano-SiO2 is established.

Preparation of Freezing and Snowing Phase Change Materials for Roads and Their Thermal Performance Study

In this paper, the phase change materials suitable for anti-icing and snow melting were investigated and optimized and the silica-based phase change materials were prepared by the sol-gel process with n-dodecane as the core material. The effects of core-shell ratio, temperature, and stirring speed on material synthesis were analyzed by DSC, SEM, and FT-IR tests. Finally, the optimal preparation temperature, stirring speed, and core-shell ratio were obtained, the exothermic peak was -14.88 °C, and the enthalpy value was 75.78 J/g. Its lower phase change temperature makes such phase change materials prepared by the sol-gel method more suitable for low-temperature areas of asphalt pavement anti-low temperature, anti-ice, and snow melting.

Green infrastructure modelling for UHI control to urban thermal comfort: a case study of Temanggung urban area

ABSTRACT The Temanggung urban area in Central Java (Indonesia) already has considerable urban Green Infrastructure (GI), but the phenomenon of Urban Heat Island (UHI) has expanded to 268% in the last seven years. This study explores the theoretical gaps related to urban thermal comfort by combining tree management modelling as the independent variable and existing urban morphology as the dependent variable to identify the right place for the right tree using ENVI-met v5 simulations. We use the Universal Thermal Climate Index (UTCI) to determine urban thermal comfort, and our results showed a temperature decrease from 37°C (strong heat stress) to 32.5°C–35.5°C (moderate heat stress) and an average decrease of 1°C–3.5°C. These results were obtained by simulating the placement pattern of substations, land use zoning, tree size composition, paying attention to the type of road surface material, wind direction and speed and direction of road orientation, average air temperature, and location of building masses. This study provides a basis for consideration to assist local governments and researchers in managing GI in Temanggung Urban Area to create comfortable urban thermal comfort for their residents.

Release behavior of soluble salts in MSWI bottom ash used as road basement materials under continuous rainfall conditions

Release behavior of soluble salts in MSWI bottom ash used as road basement materials under continuous rainfall conditions

Paving the way to the future: Mapping historical patterns and future trends of road material stock in Japan

Roads are a fundamental component of societal infrastructure, whose decades-long lifespan has far-reaching implications for developmental decisions. The road construction and development have profound impacts on economic growth, social dynamics, and environmental sustainability. Therefore, comprehensive measurement of the current road material stock (MS) and the projection of expected future road scale based on regional socio-economic scenarios that can reflect unique local conditions are necessary. This study examined the historical changes and progression patterns of the road network across Japan from 1965 to 2020 through material flow and material stock analysis. By using the road MS time series, along with explanatory socioeconomic variables, several models including Autoregressive Integrated Moving Average with explanatory variables (ARIMAX), Support Vector Regression (SVR), hybrid ARIMAX-SVR, Multiple Linear Regression (MLR), Artificial Neural Networks (ANN), and Random Forest (RF) were compared. After comparison analysis, ARIMAX and hybrid ARIMAX-SVR models were employed to forecast expected road MS in each prefecture of Japan by 2050 based on national shared socioeconomic pathways (SSP) scenarios. The study found that the total road MS of Japan increased 5.5-fold over 55 years. Aggregate was the dominant material, comprising over 70 % among the four materials of the total road MS. The forecast results for each prefecture were classified into three different patterns. Expected MS in most prefectures still displayed increasing trends in the five scenarios, but the projection of road MS in eight prefectures revealed a notable downward trend across each SSP scenario. For most prefectures, SSP5 displayed the highest expected road MS, followed by SSP1. SSP3 was the scenario with the lowest MS. This approach provided a more thorough understanding of the likely evolution of road MS across different SSP scenarios and could help inform decisions for resource allocation and policy formulation concerning road infrastructure management.

Investigation of the performance of cement-stabilized magnesium slag as a road base material

The harmless, resource-saving, and large-scale utilization of magnesium slag (MS) from industrial waste has become an important topic for road research. The use of MS as a substitute for aggregate is a practical and efficient way to dispose of it. However, there is a lack of systematic research on how to standardize its use in road construction. The objective of this study was to investigate the applicability and feasibility of using MS for cement stabilized base course materials. The influence of different cement dosages, curing age, and gradation on the strength, stiffness and stability of cement-stabilized magnesium slag mixture (CMSM) was investigated, and the actual road performance of CMSM was analyzed by paving a test road. The results showed that the mechanical properties of the CMSM met the requirements for road base courses under medium-to-light traffic when the cement dosage was above 5%. The unconfined compressive strength loss rate of the CMSM was less than 13% for an immersion time of 1 to 7 days, and after 5 freeze–thaw cycles, the frost resistance coefficient of the CMSM was more than 85%. The performance of the CMSM was most affected by cement dosage and curing age, closely followed by mixture grading type. MS can enhance the development of the pozzolanic reaction, resulting in improved strength and compactness of CMSM. Overall, CMSM exhibited exceptional road performance and could reduce aggregate costs by 25% to 35%. The use of MS as an aggregate for road base courses offers a sustainable solution that not only maximizes the use of solid wastes, but also avoids the potential safety hazards and environmental pollution caused by improper disposal and stockpiling of MS.

Preparation and performance analysis of high-viscosity asphalt containing high-content SBS and crumb rubber by oxygen-free high-temperature treatment

Styrene-butadiene-styrene (SBS) and crumbed rubber (CR) are widely used for asphalt binder modification in the field of road materials. Especially, the high-viscosity asphalt with high-content SBS/CR modifiers has been applied for constructing the porous pavement and ultra-thin overlay. However, the workability of the SBS/CR modified asphalt still needs to be improved due to many unswollen polymer particles in the blended system. This work aims to propose an oxygen-free high-temperature treatment method to reduce the viscosity of SBS/CR-modified asphalt at construction temperature for better workability. Viscosities at 60 °C and 180 °C were tested to obtain the content of SBS, CR, and tackifying resin for high-viscosity asphalt; multiple physical tests were conducted to obtain acceptable heating temperature, initial pressure, and reacting time; the two high-viscosity asphalt binders cured under various conditions were compared through physics, chemistry, and rheology properties. The results show that the 70# asphalt incorporating 10% SBS, 6% CR, and 9% (by weight of asphalt binder) resin can prepare ideal high-viscosity asphalt binders. After high-speed shearing, it was recommended that CR-SBS-asphalt blends be cured in the reactor at the initial pressure of 3 MPa and temperature of 200 °C for 45 mins. The improved reaction conditions increased light components in a homogeneous and formed a stable modified asphalt blended system. Hence, the low-temperature performance and workability were improved, despite weakening the rutting resistance, which was still excellent at the high temperature.

Physical and chemical characteristics of particles emitted by a passenger vehicle at the tire-road contact

Non-exhaust emissions are now recognized as a significant source of atmospheric particulate matter and the trend towards a reduction of conventionally fueled internal combustion engine vehicles on the road is increasing their contribution to air pollution due to lower exhaust emissions. These particles include brake wear particles (BWP) and tire-road contact particles (TRCP), which are composed of tire wear particles (TWP), road wear particles (RWP) and resuspended road dust (RRD). The goal of this study has therefore been to design an original experimental approach to provide insight into the chemical composition of particles emitted at the tire-road contact, focusing on the micron (PM10–1μm) and submicron (PM1–0.1μm) fractions. Through this characterization, an examination of the different TRCP generated by different materials (tire, road surface, brake system) was conducted. To achieve this, TRCP were collected at the rear of the wheel of an instrumented vehicle during road and track tests, and a SEM-EDX analysis was performed. Our experimental conditions have allowed us to demonstrate that, at the individual particle scale, TRCP are consistently associated with road dust materials and particles solely composed of tire or road materials are practically non-existent. The contribution of BWP to TRCP is marked by the emission of Fe-rich particles, including heavy metals like Ba, Mn and Cr. TWP, which result from rubber abrasion, consist of C-rich particles abundant in Si, Zn, and S. RWP, mainly composed of Al, Si, Fe, and Ca, can be either part of RRD or internally mixed with emitted TWP. The findings of this study highlight the substantial role of RRD to TRCP emissions under real driving conditions. Consequently, it underscores the importance of examining them simultaneously to achieve a more accurate estimation of on-road traffic emissions beyond the vehicle exhaust.

Identification of bending fracture characteristics of cement-stabilized coral aggregate in four-point bending tests based on acoustic emission

Cement-stabilized coral aggregate (CSCA) can be used as a base material for roads and airports, and it is a future direction for island engineering. In this study, four-point bending tests were conducted on notched CSCA beams with different notch depth ratios, and the specimens were monitored using acoustic emission (AE) technology. The ringing count, amplitude, RA value, frequency, and b-value were used to study the bending fracture characteristics of the CSCA material. The results of the study showed that the 28d flexural tensile strength of the CSCA beam was 0.922 MPa when the test loading rate was 0.1 mm/min. The CSCA materials exhibited brittleness during the bending fracture process. The CSCA originally had defects, internal pores, and large-diameter irregular coral aggregates, which caused beam fractures from the weak surface near the loading point. At the stage where the peak force was reduced to approximately 0.2 times the peak force, many cracks in the CSCA formed, extended, and connected, and the beams experienced dense damage. The damage to the CSCA material was dominated by tensile cracks. In the CSCA material, the combined effect of the aggregate and cement paste was enhanced, the strength of the interfacial transition zone was increased, and the strength of the aggregate was weakened compared with that of cement-stabilized macadam material. The fracture process of the CSCA material was accompanied by the destruction of the interface and fracture of the aggregate particles.