Aggregate Image Measurement System Research Articles

Evaluating Friction Characteristics of High Friction Surface Treatment Application Under Varied Polishing and Slippery Conditions

The frictional attributes of high friction surface treatment (HFST) play a crucial role in ensuring optimal traffic safety, particularly in wet weather conditions. Friction consists of two important components: adhesion and hysteresis. This research focuses on evaluating these essential factors in HFST using two different aggregates and two distinct sizes by considering various abrasion and polishing methods. To isolate these components for assessment, testing was carried out under various slippery conditions, including dry, wet with water, and wet with water + soap. The inclusion of liquid hand soap in the test procedure effectively minimized or even eliminated the adhesion component’s influence, making it possible to primarily focus on the hysteresis component. Consequently, the British Pendulum Number (BPN) measured in this research predominantly reflected the hysteresis-related friction. The analysis of variance results emphasized the substantial impact of different abrasion and polishing methods on the BPN values obtained under various surface conditions. Notably, Micro-Deval Abrasion (MDA) with 105, 180, and 240 min abrasion exhibited the most pronounced influence on BPN variation and the higher F-value for the MDA 105 min indicated that this specific abrasion time exerted a more significant influence on the variation in BPN values than other factors. Furthermore, the utilization of the Aggregate Image Measurement System yielded valuable insights into the micro-texture of the aggregates. It revealed that the calcined bauxite HFST size is anticipated to provide the rougher surface morphology (texture) on a pavement surface compared with other sources in this study, thereby contributing to high pavement surface friction. The findings from this study contribute to a deeper understanding of the frictional characteristics of HFST under different scenarios, providing valuable insights for optimizing HFST applications to enhance road safety and skid resistance.

Exploring skid resistance over time: Steel slag as a pavement aggregate—comparative study and morphological analysis

Steel slag has been investigated as a potential aggregate for pavement-wearing courses in road engineering. The volume stability, resistance to high and low temperatures, and water stability for asphalt mixtures containing steel slag have been widely studied. As for the skid resistance, previous studies have primarily focused on the initial performance. The relationship between the steel slag's appearance morphology and skid resistance during the wearing process remains to be further explored. It is essential to undertake a comparative study on the long-term skid resistance of steel slag and conventional aggregates to address the differences. This research picked two steel slags and two types of conventional aggregates (granite and limestone) as research samples. The chosen aggregate samples underwent various degrees of wear treatment with the Los Angeles abrasion machine, and their angularity was examined utilizing an aggregate image measurement system (AIMS). Based on the polishing pre-treatment, the micro-texture of the aggregates was observed with the assistance of a laser confocal microscope, and its correlation with skid resistance was determined. British pendulum number (BPN) tests were also conducted and analyzed at various polishing durations. The results show that steel slag has a low abrasion rate and higher initial angularity and abrasion resistance compared to natural stones. The micro-texture analysis demonstrates that steel slags have a coarser roughness, more contact points, and more durable abrasion resistance. Additionally, the fluctuations in BPN further prove that steel slag has superior initial and sustained skid resistance. Overall, steel slag can be a promising alternative for pavement-wearing course aggregate due to its superior long-term skid resistance.

Effects of aggregate shape on the macrotexture and performance of chip seal: a laboratory study

Chip seal is an efficient maintenance strategy for bituminous pavements, with aggregate shape significantly impacting its embedment and performance, but there is limited quantification of its effects. Using the Aggregate Image Measurement System II (AIMS-II) for shape classification, this study investigated the influence of aggregate shape on chip seal's macrotexture and performance through a series of tests, including 3D laser scanning test, aggregate coverage test, skid resistance test, and sweep test, employing response surface methodology (RSM) for quantification. Results indicated that an abundance of flat aggregates deteriorates surface quality by increasing roughness and altering texture spacing, recommending their proportion be kept under 10%. Conversely, elongated aggregates enhance performance by enriching texture depth and sharpening surface peaks. Spearman rank correlation analysis identified the arithmetic mean peak curvature (Spc ) and the root mean square height (Sq ) as reliable measures for evaluating skid resistance and aggregate retention of chip seals, respectively.

Physio-chemical characterisation of ultra-fine-slag-based ultra-high-performance concrete

Ultra-high-performance concrete (UHPC) meets the demand of modern infrastructure due to its exceptional strength and durability. The effects on concrete strength of the size and shape of fine aggregates, and binder content and type, were investigated. Particle packing concepts were adopted for fine aggregate optimisation, and the shape of the fine aggregate was assessed using an aggregate image measurement system. Further, the effects of binder content, binder type and curing age were investigated through compressive strength, thermo-gravimetric analysis (TGA) and quantitative X-ray diffraction. Mixtures with a 2.36 mm nominal maximum size of aggregates (n.m.s.a.) and angular aggregates exhibited higher compressive strength than those with a 1.18 mm n.m.s.a. No significant increase in the compressive strength was observed in mixtures with a binder content greater than the optimum 1000 kg/m3. The study also revealed that ultra-fine slag is a feasible alternative to silica fume. The TGA and X-ray results of concrete paste samples at different curing ages showed that the degree of hydration was relatively low (38.3%) with no further significant increase beyond 7 days. This work contributes to the fundamental understanding of the effect of raw materials on UHPC strength, which helps in rational selection of materials and mixture proportioning.

Geometrical characteristics of aggregates: The influence of sphericity, angularity, and surface texture on the workability of asphalt mixtures

Workability of asphalt mixtures is considered as an essential factor in quality control of asphalt pavement construction. However, there are fewer studies related to the influence of geometric properties of aggregates on the workability of asphalt mixture. The main purpose of this paper is to explore the influence of aggregate sphericity, angularity and surface texture on the workability of asphalt mixture during the mixing process. Firstly, a self-developed workability equipment of asphalt mixture was used to analyze the differences in the asphalt mixture workability of three materials, namely, basalt, limestone and pebble. Next, using the Aggregate Image Measurement System (AIMS), the geometric characteristics of the aggregates were determined. Accordingly, the correlation between the geometric characteristics of the aggregates and the workability index was established through linear correlation analysis. Finally, investigating the distribution uniformity of asphalt film by scanning electron microscope (SEM), the influence of the geometric characteristics of the aggregates on the workability of the asphalt mixture was determined. The results demonstrated that, compared with limestone and pebble asphalt mixtures, a significantly greater workability value was observed for the basalt asphalt mixture. Moreover, the geometric characteristics of the aggregates were found to influence the change rule of workability in the following order: sphericity > surface texture > angularity. Furthermore, the geometric characteristics revealed to have a significant effect on the uniformity of the asphalt film.

Predicting the Friction Coefficient of High-Friction Surface Treatment Application Aggregates Using the Aggregates’ Characteristics

Providing sufficient pavement surface friction (i.e., skid resistance) between vehicle tires and pavement surface throughout the pavement service life is considered to be one of the main objectives of highway design. Moreover, vehicle safety, the amount of consumed fuel, and the wearing rate of vehicle tires generally are influenced by pavement surface friction. In this study, a comprehensive experimental testing program was conducted on different aggregate sources, including calcined bauxite and five alternative local sources, to assess their friction characteristics. The testing program included a British pendulum tester (BPT) and a dynamic friction tester (DFT), which were used to evaluate the friction characteristics of the proposed aggregates, along with basic and durability properties tests. The aggregate imaging measurement system (AIMS) technique was applied to evaluate the aggregate characteristics due to Micro-Deval degradation. This study provides two empirical models for the friction characteristics of high-friction surface treatment (HFST)-application aggregates based on the experimental results. The first model correlates the friction coefficient at 20 km/h (DFC20) with the British pendulum number (BPN). The second model expresses DFC20 as a function of polishing resistance of aggregates, which is represented by the initial and terminal aggregate texture and angularity values measured using the AIMS device with an overall coefficient of determination (R2) of 0.949. The aggregate characteristics (i.e., particle angularity and surface texture) align well with the microtexture characteristics of the investigated sources.

Densification behavior of asphalt mixture and its relation with particle dynamic responses during gyratory compaction

Compaction of asphalt mixture is a critical step of the pavement construction, which determines the performance and durability for asphalt pavement. The densification behavior of asphalt mixture is complicated and its workability is prone to be affected by the material composition and construction conditions. Knowing the compaction process is of great significance for improving the pavement construction quality. This study aims to investigate the densification behavior of asphalt mixture in the compaction process and its correlation with dynamic responses of the built-in Smart Aggregate. Through Los Angeles abrasion tests and aggregate imaging measurement system, 40 kinds of coarse aggregates with different morphologies were prepared and employed to carry out gyratory compaction tests for asphalt mixtures. The height decline and density growth of the mixtures were concerned in different compaction stages. Meanwhile, the Smart Aggregate was embedded in the mixture to capture the particle dynamic responses, which were further correlated to the densification behavior of the mixture. The results show that material factors have the significant influence on the compaction process after the mixture has been compacted to the P1 at which the height change is less than 1 mm. The gyratory compaction process can be divided into different stages of 0∼P1, P1∼P0.1, P0.1∼P0 according to the change in mixture height, and every gyration would enable the percentage of maximum theoretical specific gravity (Gmm) increase with 1.46 %, 0.3 %, 0.11 % in the corresponding stage. After the threshold point P0, the increment of compaction degree after per gyration is less than 0.05 %. AC and SMA-13 mixtures would achieve the 95.5 %∼97.4 % of Gmm when they are compacted to locking point of P0. Asphalt mixture height is highly related to the relative rotation of the embedded Smart Aggregate. Change in the mixture height can be characterized by the variation of particle relative rotation, which could be further adopted to determine the locking state of asphalt mixture compaction in real-time.

Refined decomposition: A new separation method for RAP materials and its effect on aggregate properties

In order to high-content and high-quality use of reclaimed asphalt pavement (RAP), the separation of aged asphalt and aggregates in RAP is necessary. However, the current separation methods are either inefficient, unsafe or costly. The objectives of this study are to propose a new separation method named refined decomposition (RD) and evaluate its separation efficiency and effect on aggregate properties. Quantitative indexes of asphalt removal percentage and weight loss percentage were proposed through asphalt extraction test to evaluate the separation degree of asphalt and agglomeration degree of RAP. The morphological and mechanical properties of RAP aggregates recycled from RD process were evaluated by aggregate imaging measurement system and crushing value test. The results showed that the separation degree is about 30–45 % and the agglomeration degree is reduced by 20 % for coarse RAP using RD method. The improved stability of the processed RAP is observed as well. The strength of aggregates is slightly enhanced, the angularity is slightly reduced, and the sphericity and texture are scarcely affected after RD process. In view of the acceptable changes in properties of aggregates, the RAP materials from the efficient RD process can be used in the pavement.

Effects of Coarse Aggregate Shape Parameters on Workability, Design, and Performance Characteristics of Stone Matrix Asphalt Mixes

The present study explores the effects of coarse aggregate shape characteristics on the performance of stone matrix asphalt (SMA) mixes. The aggregates were produced with two commonly using different crushing mechanisms, namely JH (jaw-horizontal shaft impactor) and JJV (jaw-jaw-vertical shaft impactor). The digital image based Aggregate Image Measurement System was used to capture aggregate shape parameters. The effects of aggregate shape on the SMA mix were captured via various indicators, such as workability, design (resilient and dynamic modulus), and performance parameters (i.e., shear, rutting, and fracture). The shape characterization showed that aggregate produced from JH had significantly higher angularity, texture, and flat and elongated particles compared to JJV. However, the JJV-produced aggregate had significantly higher sphericity/cubicity compared to JH. Moreover, the SMA mix derived from JJV offered better rutting and shear resistance, and modulus values, while both mixes (i.e., JH and JJV) showed a similar fracture resistance behavior. Conclusively, it was perceived that aggregates having high cubicity with moderate angularity and texture offered significantly improved performance. Therefore, it can be inferred that the type of crusher can significantly affect aggregate shape characteristics and the subsequent performance of SMA mixes.

Long-term skid resistance of high-friction surface treatment of pavement using high-alumina refractory waste

• High-alumina refractory waste has a potential to be used as an alternative aggregate for HFST. • The skid resistance of the silicon carbide-mullite brick is above 90 % of that of calcined bauxite after long-term polishing. • The cross-scale difference of abrasion in post-use high-alumina refractories was explained. In this study, the feasibility of using high-alumina refractory waste, namely, silicon carbide-mullite brick (SMB) and refractory castable (RC), as alternative aggregates in high-friction surface treatment (HFST), was investigated. Calcined bauxite (CB) and basalt (BA) were used as control samples for the HFST. The long-term skid resistance of the HFST was characterised by conducting dynamic friction coefficient and mean profile depth (MPD) tests after long-term polishing using a three-wheel polishing device. Further, the 2nd generation of the Aggregate Imaging Measurement System (AIMS II) was used to determine the shape characteristics of the fine aggregates. The MPD and AIMS II results were combined to evaluate the contribution of the macrotexture to the skid resistance. Subsequently, the microtexture and mineral composition of the aggregate were tested. The test results indicated that the SMB is a suitable alternative aggregate in the HFST and can provide friction comparable to that of CB. Aggregates BA and RC exhibited a similar skid resistance: approximately 70 % that of CB. Furthermore, the anti-skid mechanism of the HFST was investigated based on the macro and micro textures of the aggregate. The structure of the refractory waste was an aggregate matrix, which can provide a richer macrostructure for the SMB. Moreover, the hardness difference between the mineral phases can produce abundant microtextures. The cross-scale difference of abrasion in post-use high-alumina refractories contributed to the skid resistance of the HFST. The results of this study help in realising the goal of clean and harmless utilisation of high-alumina refractory waste and reveal an alternative environmentally friendly aggregate for the preparation of the HFST at low cost and low energy.

Characterization of road surfacing aggregates based on their mineralogical fingerprint

To ensure the safety of infrastructure users, the long-term skid resistance is a crucial factor and is determined in large by the mineralogical and morphological characteristics of surfacing aggregate. Most studies have investigated these aggregate properties separately without considering the interrelation between one another. The objective of this study is to consider the morphological characteristics as well as the mineralogical fingerprint of aggregate to develop an innovative approach to optimize the aggregate selection process. The investigations are based on 11 different aggregate types with a broad range of mineralogy, commonly used in Germany. The long-term influence of polishing and wearing on the surface aggregate was simulated by means of the Aachen Polishing Machine and the Micro-Deval test respectively. To evaluate the impact of these tests, the aggregate shape was characterized by means of an imaging system called Aggregate Image Measurement System while the skid resistance of aggregates was evaluated with the British Pendulum Test. The test results show that the quartz and calcite are the key crystals to determine the anti-wear resistance of aggregates. A correlation between the skid resistance, morphological properties and mineralogy is derived, which proves the mineralogical fingerprint technology is practical for characterization of aggregates used in pavement surface layers. • Long-term influence of polishing and wearing on the surface aggregate is simulated. • Characterizations of the mineralogical fingerprint and morphological parameters of aggregates are determined. • Correlation between skid resistance, morphological properties and mineralogy of aggregates is derived.

Characterization of glass beads by image methods for pavement marking retroreflectivity

Road safety is a worldwide concern. Traffic injuries are the main cause of death for children and young people. One alternative to improve traffic safety is the enhancement of pavement markings visibility. Pavement marking efficiency depends on day and night visibility. Nighttime visibility (retroreflectivity) occurs due to the presence of glass beads. This paper compares the performance of two glass beads: G1 – Brazilian glass bead produced with recycled glass; and G2 – imported glass bead produced with new material. The research evaluated the retroreflectivity decrease of a test deck using two water-based paints from different manufacturers. The glass beads characterization process used the Computerized Optical Equipment (COE), CamSizer, and the Aggregate Image Measurement System (AIMS) to evaluate the shape, size, and gradation. Results indicated different retroreflectivity decrease trends for pavement markings with distinct glass beads, which could be associated with their shape characteristics and grain size distribution. The glass beads G1 presented the worst shape properties which lead to the poorest retroreflectivity at the test site. Thus, image characterization is helpful in estimating markings retroreflectivity prior to its application. Therefore, G1 cannot be used to substitute G2, regarding the retroreflectivity requirements in Brazil.

Fatigue Properties and Its Prediction of Polymer Concrete for the Repair of Asphalt Pavements.

Polymer concrete (PC) is considered a promising repair material for asphalt pavement, since it has excellent paving performance and water stability. Although the mechanical properties of PC have been widely researched, the fatigue behavior of PC under traffic loads was still poorly understood. To predict the fatigue life and optimize the material design of PC, the semi-circular bending (SCB) tests were performed, considering different polymer content, sand ratio, aggregate features and stress condition. Two typical polymer materials were applied to prepare PC specimens, including epoxy resin (ER) and polyurethane (PU). The aggregate features were analyzed by the aggregate image measurement system. The mechanical behavior under repeated loads was investigated by the displacement, fatigue life and stiffness modulus. Results show that the flexural strength increases nonlinearly with the increasing polymer content, rapidly at first, and then slowly. The optimized polymer content and sand ratio were respectively 15% and 30%. As the loading number increases, the vertical displacement of PC shows three stages, i.e., undamaged stage, damage development stage, and fatigue failure stage. The stiffness modulus of the specimen is stress-dependent. An empirical model was developed to predict the fatigue life of PC, which can effectively capture the effects of the polymer content, sand ratio and stress level (or nominal stress ratio). It suggests that the fatigue life has a strong correlation with the mixing gradation, and the optimal sand ratio of PC can be determined by the proposed function. Moreover, the effect of aggregate shapes cannot be neglected.

Particle Characterization of Manufactured Sand and Its Influence on Concrete Properties.

With the rapid development of infrastructure construction, it is an inevitable trend to replace natural sand in short supply with manufactured sand to meet sustainable development. In this paper, the relationship between the particle shape characteristics of manufactured sand and concrete performance is discussed using a morphological analysis and concrete experiments. The particle shape parameters of five types of manufactured sand were obtained by using the aggregate image measurement system (AIMS) and digital image processing (DIP) techniques, and the correlations between different parameters were analyzed. Moreover, the properties of concrete with the five kinds of manufactured sand were tested. The results show that particle size and type have a significant impact on particle shape parameters. Particle shape parameters, especially angularity, correlate well with the workability and compressive strength of concrete while having little effect on the durability of concrete. An accurate understanding of the morphological characteristics of manufactured sand is conducive to the optimization of concrete mix designs. Therefore, it is suggested that a manufactured-sand shape test be included in aggregate specification.

Examining the Influence of Aggregate Shape Properties Measured Using Imaging Technique on the Flexural Strength of Concrete

It is known that aggregate shape properties influence the quality and performance of pavement materials. Yet, there is little information available on the effect of aggregate shape properties on the flexural strength of concrete, which is the main topic of the present study. Aggregate Image Measurement System (AIMS) was used to analyze three sizes of coarse aggregate and three sizes of fine aggregate obtained from three different sources. Portland cement concrete beams were prepared and tested for flexural strength using Universal Testing Machine (UTM) according to ASTM standards. A positive relationship with a high correlation was found between some aggregate shape properties (angularity and texture) and the flexural strength of the concrete. At the same time, an inverse relation with weak correlation was noticed between flexural strength and sphericity of coarse aggregates. Meanwhile, the 2-D form of fine aggregate showed a positive relationship with a weak correlation with flexural strength. Despite showing a similar trend of effects that shape properties have on flexural strength, the shape indices showed a better correlation with flexural strength than uncompacted void content, which is used as a measure of combined shape properties in the conventional indirect test methods. Results also suggested that the shape indices measured using the imaging technique can be a good alternative for the conventional methods.

Life Cycle Cost Analysis of High Friction Surface Treatment Applications

Life cycle cost analyses for high friction surface treatment (HFST) applications were executed relying on a Microsoft Excel program developed by the researchers. Calcined bauxite (CB), five CB alternatives, and epoxy binder were utilized in the HFST applications. The aggregates’ performances were evaluated through the aggregate image measurement system (AIMS) before and after Micro-Deval polishing. The performance of the HFST applications was evaluated by the dynamic friction tester (DFT) and British pendulum (BP). The major purpose of this program was to present a rational method for converting different input data (project and material specifics) to comparable output data (net present value [NPV]) that facilitated comparison between different alternatives. The project specifics included traffic data, highway classification, and geometric design data. The material specifics data were AIMS results, DFT results, BP results, and materials and shipping costs. Three prediction models were selected to relate the performance test results to skid number (SN). The rehabilitation matrix, proposed by the researchers, was used to make the decision to maintain the HFST. This was conducted by comparing the predicted terminal SN and the recommended terminal SN (controlled by the user). The program output showed that Meramec River Aggregate and Flint HFST applications had the lowest NPVs, followed by Steel Slag HFST application, and then Earthworks HFST application. Nevertheless, Rhyolite HFST application showed the highest NPVs followed by the CB HFST application. The cost of the resin was dominant over the total cost of the HFST application.

Investigation on the relationship between the surface texture index and the surface free energy of aggregate

The surface free energy (SFE) of aggregate and asphalt binder can be utilized to quantify the adhesion between the aggregate and binder. The SFE value varies with the changing surface characteristics. This study investigated the effect of surface texture on the aggregate’s SFE when applying the contact angle measurement. A surface treatment protocol for granite, diabase, basalt, and limestone was designed. A dicing saw, grinder and abrasive paper were utilized and were combined into three groups to treat the aggregates’ surface — Groups A, B, and C. The group in which aggregate was not treated was labeled Group D. The aggregate image measurement system (AIMS) was employed to quantify the surface characteristic. After surface treating, four levels of surface texture index were obtained. The surface texture indexes of the treated aggregates followed an increasing rank: A < B < C < D. A higher surface texture index indicated higher surface roughness. Subsequently, the sessile drop method was utilized to measure the contact angle and obtain the SFE of the aggregates that been treated through Groups A, B, and C. The gas adsorption method was applied to determine the SFE of aggregates in Group D. With the increasing surface texture index, the contact angle also increased and resulted in an increasing SFE value. An exponential-type model was established to describe the relationship between surface texture index and SFE. The model was first employed to fit the SFE data of aggregates in the A, B, C, and D groups, which showed good satisfaction of model fitting. The model was also applied to fit the SFE data of aggregates in the A, B, and C groups and to predict the SFE values based on the surface texture index obtained in Group D, which indicated good predictability. The fitting parameters showed a variable coefficient within 20% in the two fitting methods, which confirmed the model was reliable.

PERFORMANCE EVALUATION OF RAILWAY BALLAST DEGRADATION USING THE MORPHOLOGICAL PROPERTIES

Ballast degradation through attrition and breakage during operations affects the structural performance of the railway track system. In an attempt to study railway ballast degradation changes due to train cyclic loading at micro-scale. This study quantified and compared the changes that occur on ballast particles due to ballast degradation using LAA test and image analysis techniques. TB/T 2328.14-2008 gradation use by china railways was adopted. Series of LAA tests were conducted to accelerate the ballast particle breakage and abrasion, in a sequence of 250 turns of the LAA test drum, after which the changes in gradation and morphological properties were quantified. The morphological properties were quantified using imaging techniques (Aggregate Image measurement system (AIMS)). At the end of the study, the overall results showed that ballast degradation has a strong correlation with the ballast particle's morphological properties. The relationships and the indices of morphological changes can be used for numerical modeling and simulations using discrete element method (DEM) to study the performance of ballast at different degradation levels.

Effect of waste glass aggregate on performance of asphalt micro-surfacing

Huge amounts of waste glass are produced every year in China, which brings great pressure on the environment. Meanwhile, a large number of natural aggregates are required for highway construction every year. In this study, it is intended to prepare asphalt micro-surfacing materials using waste glass as aggregate and evaluate their performance. The morphology of basalt and waste glass was quantitatively analyzed through aggregate image measurement system to characterize the morphological differences. In addition, the wet stripping test, wet track abrasion test, wheel load test, sand patch test and British pendulum test were used to investigate the resistance to the action of water, the wear performance, rutting resistance and skid resistance of asphalt micro-surfacing mixtures. The results indicate that the two-dimensional (2D) form of waste glass is more abundant than that of basalt, and as the content of waste glass increases, the British pendulum number (BPN) value and the texture depth (TD) value of micro-surfacing mixtures increase, which means that the addition of waste glass can improve the skid resistance ability of micro-surfacing mixtures to some extent. The abrasion loss, lateral and vertical displacement are all increased after replacing basalt with waste glass due to its brittleness and weak bonding. Considering the feasibility of mechanical properties, it is recommended that the maximum volume amount of fine waste glass and coarse waste glass should be less than 15% and 10%, respectively. The potential use of waste glass can alleviate the overconsumption of natural resources and is a good choice for applying in micro-surfacing pavement materials.

Fabrication and numerical verification of two-dimensional random aggregate virtual specimens for asphalt mixture

This paper proposes a two-dimensional (2D) virtual specimen fabricating method to create 2D virtual specimens that can accurately characterize the microstructure of asphalt mixtures. In this method, the gradation of the 2D aggregate area and the proportion of 2D voids area are calculated by the phase separation method. Random aggregates are generated by using the geometric characteristics database of random aggregates, which is established by the Aggregate Image Measurement System (AIMS). The random aggregate placement angle is determined according to the aggregate angle distribution law. Random aggregates are placed using a method that accurately identifies the scope of the conflicting judgment, and the random voids are generated with image binarization. Four AC-13 2D random aggregate virtual specimens with the same gradation were generated in this research to verify the practicability and effectiveness of the virtual specimen fabricating method. Virtual complex modulus parallel tests were performed on these four virtual specimens in COMSOL finite element software. By comparing the calculated results with the lab test results, it was found that the 2D random aggregate virtual specimens generated by the method proposed in this paper adequately predict the complex modulus of asphalt mixtures. The virtual test is repeatable and provides new ideas and references to creating virtual specimens for asphalt mixtures.