Gyratory Compaction Test Research Articles

Study on the Road Performance and Compaction Characteristics of Fiber-Reinforced High-RAP Plant-Mixed Hot Recycled Asphalt Mixtures.

Recycled asphalt pavement (RAP) mixtures are widely adopted due to their significant economic and social benefits from utilizing pavement recycling materials. This study incorporates basalt fibers (BF) and polyester fibers (PF) into plant-mixed hot recycled asphalt mixtures to analyze their enhancement effects on the high-temperature, low-temperature, and fatigue performance at different RAP content levels. Additionally, the study investigates the impact of fiber and RAP additions on the compaction characteristics of the mixtures using gyratory compaction tests, aiming to increase the RAP content of plant-mixed hot recycled asphalt mixtures. Experimental results demonstrate that at 30% and 50% RAP content levels, basalt fibers exhibit more pronounced enhancement effects on the performance of recycled asphalt mixtures compared to polyester fibers. Incorporating basalt fibers increases the fracture energy of recycled asphalt mixtures by 8.63% and 13.9%, and improves fatigue life by 154% and 135%, respectively. Moreover, the addition of both types of fibers increases compaction difficulty, with polyester fibers showing a more significant influence on the compaction energy index (CEI).

Micro-structural characterization of the lubrication behavior of asphalt binder during the compaction of asphalt mixture

This study aims to investigate the lubrication behavior of asphalt binder on the basis of Stribeck tribology theory, employing viscosity test, gyratory compaction test, and image processing techniques. The quantification of the lubrication regimes and their transformation was performed by an image processing algorithm that measures the thickness of the mortar film based on the minimum distance. The hydrodynamic regime transforms into the elasto-hydrodynamic regime by 23.2% below 60 gyrations. 11.6% of the elasto-hydrodynamic regime transforms into the mixed regime above 60 gyrations, causing an increase in friction. The slope of the compaction curve follows the variation rule of the Stribeck friction coefficient. Asphalt viscosity in the range of 380–460 mPa·s is recommended for optimum compaction.

Comparison of gyratory compaction effect on coarse and fine-grained soils

Filling materials should have high strength and required gradation. It is important to determine properties of the filling material in the laboratory to satisfy required codes. The optimum water content and maximum dry unit weight can be designated by performing Proctor tests, which have been used for nearly a century. The impact loads are used to compress the soil in an inflexible mold in Proctor tests, but in reality, field compaction methods rely on a combination of kneading, vibration, and augmented normal pressures to achieve required densities in field. In this study, firstly standard proctor tests, modified proctor tests and Supervave Gyratory Compaction tests were conducted on different soil types. Then the compression curves were compared and the statistical analysis (ANOVA) were performed to find out the best methodology. Dry unit weight obtained using the SGC were compared with the maximum dry unit weight obtained using laboratory impact methods. The results showed that soil samples compacted with a gyratory compactor give the same performance over impact compaction methods.

Mathematical Modeling of Pavement Gyratory Compaction: A Perspective on Granular-Fluid Assemblies

The compaction of asphalt mixture is crucial to the performance of the pavement. However, the mix design (i.e., porosity, aggregate size distribution, binder content), which is based on compaction results, remains largely empirical. It is difficult to relate the aggregate size distribution and the asphalt binder properties to the compaction curve in both the field and laboratory compaction of asphalt mixtures. In this paper, the author proposes a simple mathematical model from the perspective of granular physics to predict the compaction of asphalt mixtures. In this model, the compaction process is divided into two mechanisms: (i) viscoplastic deformation of an ordered granular-fluid assembly, and (ii) the transition from an ordered system to a disordered system due to particle rearrangement. This model could take into account both the viscous properties of the asphalt binder and the grain size distributions of the aggregates, where the viscous deformation is calculated with a proposed governing equation and the particle rearrangement effect is solved using simple DEM simulations. This model is calibrated based on the Superpave gyratory compaction tests in the pavement lab, and the R-squares of model predictions are all above 0.95. The model results are compared with experimental data to show that it can provide good predictions for the experiments, suggesting its potential for enhancing the design of asphalt mixtures.

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.

Study on the Compaction Performance and Its Key Influencing Factors of Asphalt Mixture Based on Intelligent Sensing Techniques

Real‐time and accurate compaction quality monitoring is one of the key steps in the pavement construction. In this study, the effect of roller passes and temperature on the compactness of asphalt mixtures and its uniformity is discussed using the semivariance function. Further, the indoor asphalt mixture gyratory compaction test was carried out based on the embedded SmartRock sensor, with the aim of monitoring the changes in rotation and contact forces between aggregates. In addition, the effect of temperature on the dynamic response of SmartRock is discussed, and the compaction mechanism of asphalt mixtures is investigated from a microscopic scale. It is found that compaction degree and uniformity are not always positively correlated with the number of roller passes and that excessive compaction leads to a decrease in compaction effect; meanwhile, the variation in the compactness of asphalt mixtures can be characterized by the dynamic response of SmartRock, which providing a feasible method for real‐time monitoring of the compaction process and optimization of the construction plan.

Compaction characteristics assessment of cold mix patching materials through gyratory shear compactor

Cold mix patching materials (CMPMs) are widely employed in pothole repair due to ease of installation and environmental benefits. In order to generate long-lasting pavement repairs, CMPMs must guarantee adequate volumetric properties, which in turn determine a proper pavement serviceability. In this context, the present study aims to provide an improved understanding of the compaction process of CMPMs through a laboratory campaign based on gyratory compaction tests carried out under a wide range of energy. To this end, the volumetric response of nine ready-to-use CMPMs and the evolution of shear stress along their densification process have been investigated at different temperatures.Based on both densification and shear stress curves, two modelling approaches are here presented by the authors. Results demonstrate that the proposed s-shaped function enables densification curves to be studied with a high reliability and provides distinctive parameters to characterize the CMPMs at different stages of compaction. Moreover, the analysis of shear stress data through a two-stage model highlights a certain correlation among physical and mechanical responses of studied mixtures.

Reducing Compaction Temperature of Asphalt Mixtures by GNP Modification and Aggregate Packing Optimization.

Compaction of hot mix asphalt (HMA) requires high temperatures in the range of 125 to 145 C to ensure the fluidity of asphalt binder and, therefore, the workability of asphalt mixtures. The high temperatures are associated with high energy consumption, and higher NOx emissions, and can also accelerate the aging of asphalt binders. In previous research, the authors have developed two approaches for improving the compactability of asphalt mixtures: (1) addition of Graphite Nanoplatelets (GNPs), and (2) optimizing aggregate packing. This research explores the effects of these two approaches, and the combination of them, on reducing compaction temperatures while the production temperature is kept at the traditional levels. A reduction in compaction temperatures is desired for prolonging the paving window, extending the hauling distance, reducing the energy consumption for reheating, and for reducing the number of repairs and their negative environmental and safety effects, by improving the durability of the mixtures. A Superpave asphalt mixture was chosen as the control mixture. Three modified mixtures were designed, respectively, by (1) adding 6% GNP by the weight of binder, (2) optimizing aggregate packing, and (3) combining the two previous approaches. Gyratory compaction tests were performed on the four mixtures at two compaction temperatures: 135 C (the compaction temperature of the control mixture) and 95 C. A method was proposed based on the gyratory compaction to estimate the compaction temperature of the mixtures. The results show that all the three methods increase the compactability of mixtures and thus significantly reduce the compaction temperatures. Method 3 (combining GNP modification and aggregate packing optimization) has the most significant effect, followed by method 1 (GNP modification), and method 2 (aggregate packing optimization).

Research on application feasibility of limestone in sublayer of Double-Layer permeable asphalt pavement

In double-layer permeable pavement, upper layer provides better road performance, and sublayer ensures better lateral drainage capacity. The mechanical properties of limestone are weak, so its application in upper layer is limited, while the sublayer does not directly contact with vehicle load, and the application feasibility of limestone aggregate in sublayer of double-layer permeable asphalt pavement is confirmed in this paper. Optimum asphalt contents and reasonable number of Marshall blows of limestone and basalt PAC-16 (Permeable Asphalt Concrete mixture whose nominal maximum aggregate size is 16 mm) were determined, temperature stability, water stability and water permeability were obtained. Gyratory compaction tests were designed and the compaction characteristics, mechanical properties and aggregate crushing characteristics of limestone and basalt PAC-16 were investigated. Considering the disadvantages of the existing testing methods, the concept of “actual crushing proportion (ACP)” was proposed to calculate the crushing degree of aggregate in mixture under load. It was found that the optimum asphalt content of limestone PAC-16 was higher than that of basalt mixture, and the laboratory properties related to field performance of limestone PAC-16 met the requirements of specifications in general. The equivalent compacting times of limestone mixture are slightly less than that of basalt in order to achieve the same void ratio, and the void ratio decay rate of limestone mixture is much faster than that of basalt mixture after opening to traffic. The ACP results showed that limestone aggregate > 13.2 mm can be replaced by basalt aggregate to ensure the strength of aggregate skeleton.

Investigation of warm mix epoxy asphalt compaction with gyratory compactor and charge coupled photoelectric imaging

The object of this paper is to investigate the compaction characteristics of warm mix epoxy asphalt concrete with the aid of the viscosity test, gyratory compaction test, and two-dimensional image analysis. The compactability energy required from initial densification to 97% Gmm for epoxy asphalt concrete (CDIE) was proposed from the gyration compaction curve to evaluate the effect of curing temperature, curing time, and compaction effort on material workability. Microstructural indices in the sectional images of warm mix epoxy asphalt concrete specimen were obtained considering the same conditions with compactability energy. Results show that the viscosity of epoxy asphalt binder and mastic both increase over the curing time. The higher temperature is, the faster viscosity will increase. On the basis of compactability energy, a specific range of curing time exists in which warm mix epoxy asphalt concrete can be easily compacted. Two-dimensional images obtained from charge-coupled device photoelectric scanner indicate that aggregate orientation, aggregate distribution, aggregate contact, and proximity asphalt mortar film thickness are all affected by compaction effort and curing time. The overall test results show that Stribeck tribology theory could describe the internal friction change of warm mix epoxy asphalt concrete during the gyration compaction test. Based on the internal friction results, the epoxy asphalt mastic viscosity ranging from 100 to 200 Pa·s is recommended as the optimal for the compaction of warm mix epoxy asphalt concrete.

Test and evaluation for effects of aggregates fragmentation on performance of lightweight asphalt concrete

Effects of aggregates fragmentation on performance of lightweight asphalt concrete are studied in this paper. The Marshall mixture design method was used to determine the optimum asphalt content of lightweight SMA-13 (LSMA-13). Gyratory compaction test was taken to simulate aggregates crushing. British Pendulum Tester, sand patch method, rutting test, indirect tensile strength test, freeze–thaw splitting test and soaked Marshall stability test were adopted to study the effects of aggregates fragmentation on friction, high temperature stability, low temperature crack resistance and moisture susceptibility of LSMA-13, respectively. The results show that lightweight aggregates have little effects on the fragmentation of basalt aggregates whose particle size is larger than that of lightweight aggregates, but can prevent the basalt aggregates whose particle size is smaller than that of lightweight aggregates from breaking. The number of gyrations and the replacement percentage of lightweight aggregates have negative effects on the aggregates fragmentation index (AFI) of LSMA-13. LSMA-13 have good skid resistance and the effects of aggregates fragmentation on friction of lightweight asphalt concrete are not obvious. The larger the AFI value is, the smaller the dynamic stability (DS) is. And when AFI is larger than 6%, DS of LSMA-13 is smaller than DS criteria (3000 mm−1). 6% can be used as the AFI criterion of LSMA-13 for pavement engineering. Moreover, the effects of aggregates fragmentation on low temperature crack resistance of LSMA-13 are not obvious. The replacement percentage of lightweight aggregates of LSMA-13 has negative effect on its low temperature crack resistance. And the aggregates fragmentation of LSMA-13 has positive effect on its moisture susceptibility. LSMA-13 are not recommended to be applied in cold regions engineering, but are recommended to be applied in rainy regions engineering.

Durability of hot and warm asphalt mixtures containing high rates of reclaimed asphalt at laboratory scale

Within the framework of a sustainable development, manufacturing bituminous mixtures while reducing energy and using less new aggregates and new bitumen may be considered as an important topic, according to the quantities of asphalts mixtures produced for creating and maintaining road networks. This work aims to study the interest and the potential problems when coupling the warm mix asphalt technology (WMA) and the use of high ratio of reclaimed asphalt pavement (RAP) in the mixture. Initially, a study on managing RAP is performed, aiming to show that separating RAP aggregates in several fractions leads to a higher control of RAP in terms of homogeneity. Homogeneity of RAP is a key point for increasing recycling rates. The present study coupling WMA and RAP is based on the French design method for manufacturing asphalt concretes, which includes gyratory compaction tests, French wheel tracking tests, complex modulus tests and fatigue tests. However, the French design method does not take into account the physical and chemical aging of bituminous mixtures with time. As we consider that coupling WMA and RAP may lead to aging problems, it was decided to use an aging process before performing the standard tests. The results show that a WMA containing a high ratio of RAP has good performances according to the standard relative to this material, whatever the test. However, this material tends to be more sensitive to fatigue than hot and warm mixes without RAP.

Performance comparative analysis of stone mastic asphalts with electric arc furnace steel slag: a laboratory evaluation

The paper presents the results of a laboratory study, aimed at verifying the possibility to use two particular typologies of electric arc furnace (EAF) steel slags, in substitution of the natural aggregates, in the composition of stone mastic asphalt (SMA) for flexible pavements. The research has been articulated in a preliminary study of the chemical, leaching, physical, and mechanical properties of the EAF steel slag, and in the following mix design and performance characterization of the bituminous concretes, through gyratory compaction tests, permanent deformations tests, stiffness modulus tests at various temperatures, fatigue tests and indirect tensile strength tests. All the mixtures with EAF slag have satisfied the requisites for acceptance in the road sector technical standards, thus resulting as suitable for use in the construction of road infrastructures, moreover presenting higher mechanical characteristics than those of the corresponding asphalts with full natural aggregate.

Mix design and performance analysis of asphalt concretes with electric arc furnace slag

The paper presents the results of a laboratory study, aimed at verifying the possibility to use two particular typologies of electric arc furnace (EAF) steel slags, in substitution of the natural aggregates, in the composition of wearing course asphalt concrete for flexible pavements. The experimental research has been articulated in a preliminary study of the chemical, leaching, physical, and mechanical properties of the EAF steel slag, and in the following mix design and performance characterisation of the bituminous conglomerates, through gyratory compaction tests, permanent deformations tests, Stiffness Modulus tests at various temperatures, fatigue tests and indirect tensile strength tests. All the mixtures with EAF slag have satisfied the requisites for acceptance in the road sector technical standards, thus resulting as suitable for use in the construction of road infrastructures, moreover presenting higher mechanical characteristics than those of the corresponding asphalts with full natural aggregate.

Experimental evaluation of high performance base course and road base asphalt concrete with electric arc furnace steel slags

The paper presents the results of a laboratory study aimed at verifying the use of two types of electric arc furnace (EAF) steel slags as substitutes for natural aggregates, in the composition of base course and road base asphalt concrete (BBAC) for flexible pavements. The trial was composed of a preliminary study of the chemical, physical, mechanical and leaching properties of the EAF steel slags, followed by the mix design and performance characterization of the bituminous mixes, through gyratory compaction tests, permanent deformation tests, stiffness modulus tests at various temperatures, fatigue tests and indirect tensile strength tests. All the mixtures with EAF slags presented better mechanical characteristics than those of the corresponding asphalts with natural aggregate and satisfied the requisites for acceptance in the Italian road sector technical standards, thus resulting as suitable for use in road construction.

Evaluation of Pervious Concrete Workability Using Gyratory Compaction

Portland cement pervious concrete (PCPC) is increasingly used across the United States, and this has prompted various entities to begin the process of developing standardized test techniques. A major issue with placing PCPC is the inconsistencies in concrete workability between mixtures developed in the laboratory and in the field. It is therefore urgent to properly determine workability of pervious concrete and to ensure that the designed concrete mixtures are suitable for particular compaction methods and field conditions. This paper describes a new test method for characterizing PCPC workability—the gyratory compaction test method. A modified Superpave gyratory compactor (SGC) is employed in the present study. Two PCPC workability parameters are defined from the gyration compaction curve: (1) workability energy index, which describes initial concrete workability and (2) compaction densification index, which describes the resistance of the tested mixture to further compaction. The effects of binder content and water-to-cement ratio as well as effect of concrete mixing time on PCPC workability are studied. Based on the test results, values of the workability parameters for concrete with various degrees of workability are specified.

Ensayo de compactación giratoria en suelos como alternativa al ensayo de compactación proctor

El propósito de este trabajo es analizar experimentalmente una metodología alternativa para el proceso de compactación de suelos en laboratorio. Tradicionalmente se ha utilizado el método conocido como “compactación proctor”, aunque siempre se ha reconocido que no representa fielmente las condiciones en que se produce la compactación en el campo. En el ensayo de compactación giratoria, el proceso se produce por amasado, lo cual asemeja mejor el efecto de los equipos de vibrocompactación en obra. Se realizaron diferentes ensayos con presiones verticales entre 100 y 400 kPa, se mantuvo constante el ángulo de giro (1.25º) y el material se ensayó con diferentes contenidos de humedad. Con los resultados de los ensayos se determinó que para obtener una curva de compactación similar a la conseguida en el ensayo de proctor modificado se pueden utilizar dos opciones, la primera es trabajar con una presión vertical de 400 kPa, 100 giros y ángulo de 1.25º y la segunda opción es aplicar una presión 350 kPa, 300 giros y un ángulo de 1.25º.

Laboratory Simulation of Field Compaction Characteristics on Sandy Soils

As a result of the development of much heavier earth-moving and vibratory roller compaction equipment, soil compaction densities in the field are reaching levels that are not attainable in the laboratory. Higher compaction efforts, routinely seen in the field, not only result in higher unit weights but also lower optimum moisture contents than those found by the modified Proctor test. An experimental study was undertaken to evaluate field and laboratory compaction characteristics and to study laboratory compaction techniques further, such as gyratory compaction, in addition to impact and vibratory compaction, for the laboratory simulation of field compaction of A-3 sandy soils. Field test sections were constructed using typical field compaction techniques of today. Earth pressure cells were installed at the base of each lift to monitor total vertical stresses. A series of laboratory gyratory compaction tests for A-3 soils were conducted. Factors including vertical pressure, gyration angle, and gyration numbers were evaluated for the effects on the dry unit weight. The gyratory compaction curves using 200-kPa (29 psi) vertical pressure, a 1.25-degree gyration angle, and 90 gyrations were close to the field compaction curves.