Permanent Deformation Research Articles

Forearc faults in northern Cascadia do not accommodate elastic strain driven by the megathrust seismic cycle

We employ numerical models to explore the connection between subduction zone coupling or megathrust rupture and upper plate faults in the northern Cascadia forearc. Active forearc faults north of the Olympic Peninsula exhibit similar characteristics: west-northwest strike, oblique right-lateral slip senses, and low slip rates (<1 mm/yr), but a potential to generate large (M ~ 7) earthquakes. Previous hypotheses suggest that stress in the upper plate due to interseismic coupling or coseismic rupture along the subduction zone interface could drive permanent forearc strain. To test these hypotheses, we used a 3D boundary element method model to predict slip on the LRDM if interseismic coupling or coeseismic rupture cause deformation. Our model predicts reverse left-lateral slip if the strain results solely from subduction zone coupling, or normal right-lateral slip if these faults accommodate strain during a megathrust rupture. These results contradict the observed fault kinematics. Additionally, if we use our model to mimic strain partitioning, where only the strain from the strike-slip component of subduction zone coupling is accommodated in the forearc, our results are also inconsistent observed fault kinematics. These models challenge the hypothesis that subduction zone coupling or coseismic rupture are the primary driver of permanent forearc deformation in northern Cascadia.

Assessing the impact of discarded plastic bottles on the resistance to rutting in hot mix asphalt

Undoubtedly, the damage to the upper layer of road pavement caused by the tremendous load of vehicles and climate factors is alarming and challenging to both the government and researchers in the respective field. Addressing these challenges requires innovative solutions to enhance pavement durability and sustainability. In this context, the authors seek to assess the impact of incorporating waste polyethylene terephthalate (PET) as a modifier on asphalt mixture properties. This study investigates the potential of PET, a commonly discarded plastic, to improve the performance of asphalt pavements. The authors conducted evaluations on the rutting performance of asphalt blends containing different PET percentages (0%, 0.2%, 0.6%, 0.8%, 1%) and diverse PET sizes (12 × 3 mm, 20 × 3 mm, and 30 × 4 mm). The experimental approach included dynamic creep tests and the use of a Hamburg wheel tracking device to simulate real-world traffic conditions and measure the mixtures' resistance to deformation. The findings revealed that incorporating PET into asphalt mixtures significantly enhances rutting resistance. Specifically, the addition of PET content improved the viscoelastic properties of the asphalt, making it more resistant to permanent deformation under load. However, the size of PET particles was found to play a crucial role in performance. Larger PET sizes were associated with a decrease in rutting resistance, suggesting an optimal particle size must be determined to maximize benefits. These results support the idea that the careful selection of PET content and size can significantly improve the performance and longevity of asphalt pavements. This approach not only addresses the issue of plastic waste but also contributes to the development of more sustainable infrastructure. By incorporating PET, the research highlights a viable method for enhancing road durability and supporting environmental sustainability, offering a promising solution for future road construction projects.

The performance of transmission pipelines on February 6th, 2023 Kahramanmaras earthquake: a series of case studies

AbstractThe Mw 7.8 earthquake that struck Kahramanmaras on February 6, 2023, caused significant damage to hydrocarbon and water transmission lines due to permanent ground deformations. Explosions occurred in the Kahramanmaras–Gaziantep Natural Gas transmission pipeline causing disruption of gas in the cities of Gaziantep and Hatay Fault Displacement Hazard. Water transmission pipelines were also damaged due to extreme fault offsets. This paper presents the findings from the earthquake affected zones. Particular attention was given to the performance of the 2600 mm diameter Duzbag–Gaziantep water transmission pipeline due to three reported challenges: (#1) The behavior of the pipe in the Duzbag tunnel, (#2) The pipe bend behavior at the fault crossing, and (#3) The pull-out of the pipe at valve room. Based on field observations, extreme damage forms at pipes were presented. A three-dimensional nonlinear numerical analysis was performed to simulate the observed damage of the reoriented water pipe at the fault crossing for Case #2. The nonlinear finite element model was able to capture the complex nature of the post-yield behavior of steel pipe as well as the damage locations along the pipe and their sequence of occurrences. As a mitigation measure for new pipes, the need for using flexible connections at critical crossings was highlighted. For existing pipes, the importance of developing secondary (by-pass) lines was emphasized.

Experimental analysis of the kinematics in the elastic collision between two bodies during the contact time

The elastic collision between two bodies is a fleeting event challenging to observe due to its infinitesimally short contact time, usually lasting mere hundredths or even thousandths of a second. This brief duration poses significant challenges for accurately measuring velocities and impulsive forces and establishing representative functions. Consequently, this study aims to address these challenges. Experimental measurements of velocity, acceleration, and force changes during the contact period are crucial for validating theoretical models and functions that accurately represent the dynamics of collisions under realistic conditions. These measurements are critical in optimizing the activation response of airbag and restraint systems in vehicles and are fundamental in reconstructing physical scenarios of accidents. The experiments were conducted in a practical computer-assisted laboratory, utilizing wireless sensors embedded within the test vehicles and positioned on a low-friction track. The collision setup was designed to be horizontal and frontal, ensuring that the bodies involved did not undergo permanent deformations. The primary methodology adopted in this analysis integrates both quantitative and qualitative approaches, focusing on collecting and analyzing numerical data to identify patterns and establish mathematical relationships between variables. This integrated approach offers a more comprehensive understanding of the kinematics of colliding vehicles during the contact period.

Performance Evaluation and Modification Mechanism Analysis of High-Viscosity Modified Asphalt

Abstract High-viscosity modified asphalt (HVMA) has important application potential in pavement engineering, such as porous asphalt pavements and ultrathin overlays. To comprehensively study and evaluate the overall performance of HVMA, five HVMA samples were prepared using modifier with dosages of 6 %, 9 %, 12 %, 15 %, and 18 %, respectively. The basic physical properties of HVMA were evaluated according to standard physical asphalt performance tests. The overall rheological properties of HVMA were assessed using temperature sweep tests, frequency sweep tests, and multiple stress creep recovery tests. Fluorescence microscopy was employed to analyze the microscopic characteristics and the modification mechanism of HVMA. The results show that the high-viscosity modifier could improve the overall rheological properties of HVMA at both high and low temperatures, with approximately 9 % determined as the optimal dosage. HVMA had better performance than matrix asphalt in high-temperature rutting resistance, permanent deformation resistance, temperature sensitivity, and elastic characteristics. At an appropriate dosage of the high-viscosity modifier, the modifier absorbed the light components in the asphalt, causing them to swell and dissolve. As a result, the modifier could be uniformly dispersed in the asphalt, thereby significantly improving the high-temperature stability of HVMA. The results of this paper may be helpful to the mechanism research and application of HVMA.

Hubungan Antara Rasio Agregat dan Volumetrik dalam Menentukan Kualitas Perkerasan Jalan

Road pavement quality is a critical factor in supporting a country's mobility and economy. Around 40% of the road length in Indonesia suffers damage, including permanent deformation and early cracking. To overcome road damage, it is important to know the pavement quality parameters such as Voids in Mineral Aggregate (VMA), Voids in Mix (VIM), and Voids Filled with Bitumen (VFB), along with the factors that influence them, such as material characteristics. This study aims to determine the effect of the fine and coarse aggregate ratio on volumetric parameters in asphalt mixtures, including VIM, VMA, and VFB. The experimental method was carried out on four samples. Aggregate characteristic tests were carried out, including gradation tests. Volumetric tests were carried out on each sample with asphalt content of 4%, 4.5%, and 5%. The research results show that the smaller fine-to-coarse aggregate ratio would increase the VMA and VIM values and decrease the VFB value. Aggregate ratio significantly affects volumetric parameters, which shows the importance of selecting aggregate with the right size distribution and determining the right ratio to achieve optimal pavement performance. The results of this study can be used as a practical guide for optimizing asphalt mix design with better quality and durability.

Damage characterization of high- and low-temperature performance of porous asphalt mixtures under multi-field coupling

Porous asphalt (PA) have attracted considerable interest due to their functional advantages such as significant water permeability and noise attenuation properties. Nevertheless, its vulnerability to damage significantly hinders its widespread application. Therefore, this paper aims to investigate the damage characteristics of PA's high- and low-temperature performance under the coupled effects of moisture and temperature. Firstly, Hamburg Wheel-Tracking Test (HWTT) and three-point bending tests were conducted on PA under different coupling conditions. Subsequently, its damage characteristics were analyzed using the three-stage permanent deformation model, logistic model, and two-way analysis of variance (ANOVA) method. The findings indicate that under dry conditions, PA-13 exhibits a linear decrease in rutting resistance within the temperature range of 40–60 °C, followed by a significant decrease at 70 °C. During immersion in water, PA-13 undergoes a second and third-stage rutting evolution process, with an accelerated creep rate observed at 70°C. High temperatures exacerbate the viscoelastic damage of PA-13, while multi-field coupling promotes the simultaneous occurrence of viscoelastic damage and stripping damage. Furthemore, the results of the two-way ANOVA indicate that moisture has a more significant impact on high-temperature performance damage. In addition, in a dry environment, the low-temperature crack resistance of PA-13 deteriorates with decreasing temperature, but there is little difference at −20 °C and −30 °C. This is attributed to PA-13 exhibiting flexible cracking at 0 °C and −10 °C, while undergoing brittle cracking at −20 °C and −30 °C. Additionally, the coupled effect of temperature and moisture reduces the damage tolerance of PA-13 and accelerates its cracking process. The results of the two-way ANOVA indicate that both low temperature and treatment methods have a statistically significant impact on low-temperature performance, with treatment methods having a higher degree of influence. The findings of this paper contribute to an in-depth understanding of the damage mechanism of PA-13.

Effects of warm-mix additives, anti stripping agent, and graphene nanoplatelet on the cracking resistance, moisture susceptibility, and cost effectiveness of stone mastic asphalt

Moisture and cracking damages are two of the most common asphalt pavement distresses in the United States. The use of stone matrix asphalt mixture has gained popularity due to its high durability, resistance to permanent deformation and cracking, and reduced noise pollution. Warm-mix additives and nanomaterials have also gained significant interest as promising asphalt binder additives. In order to achieve enhanced resistance to moisture and cracking in extremely wet regions, this study investigated the effects of three warm-mix additives, an anti-stripping agent, and one nanomaterial (graphene nanoplatelet) on the cracking and moisture resistance performance of stone matrix asphalt. Fourier transform infrared spectroscopy and sessile drop tests were used to evaluate the functional groups and moisture susceptibility of the modified asphalt binder blends, respectively. The indirect tensile asphalt cracking test and the modified Lottman tests were used to evaluate the mixtures' resistance to cracking and stripping damage. A cost-effectiveness analysis as well as a two-dimensional performance interaction diagram were employed based on the laboratory performance of the mixtures. Results indicated that the graphene nanoplatelet modification of the asphalt binder had the highest wettability potential, adhesion, and debonding properties, as well as moisture resistance potential compared to other additives. In terms of mixture cracking performance, both the graphene nanoplatelet and a chemical warm-mix asphalt significantly improved the mix cracking performance by 34.1 and 30.0 %, respectively, compared to the control mix. However, the graphene nanoplatelet modification had a tensile strength ratio of 0.76, which is below the acceptance threshold of 0.80 set by AASHTO T 283 for moisture damage resistance of asphalt mixture. Overall, all mixtures with warm-mix additives showed adequate cracking and stripping damage resistance performance and are expected to be cost-effective.

Impact of aggregate gradation and asphalt-aggregate ratio on pavement performance during construction using back propagation neural network

This paper evaluates the influences of variations in asphalt mixture parameters during construction on the variations of pavement performance using back-propagation (BP) neural networks. The variations of gradation (VG) and asphalt-aggregate ratio (VRa) were assessed through a variability analysis. The influences of VG and VRa propagation were analyzed via BP neural networks and a sensitivity analysis. A reliability assessment was conducted to evaluate the joint effects of VG and VRa. Results illustrate that the VG and VRa during transportation are more severe than those during other processes. BP neural networks can precisely and robustly trace the influences of the VG and VRa. Pavement performance exhibits greater sensitivity to VRa and VG at sieve sizes of 0.075 mm and 2.36 mm. The joint effects of VG and VRa significantly degrade permanent deformation more than fatigue life. High-quality paving effectively mitigates the negative impacts of segregation during transportation.

Prediction of Damage and Remaining Life of Yogyakarta-Bawen Toll Road Pavement with Elastic and Viscoelastic Approaches

Toll roads are one of the infrastructure development targets in Indonesia to speed up traffic and vehicle travel times. This paper analyzes the flexible pavement structure of the Yogyakarta-Bawen Toll Road. It predicts damage and residual values using elastic and viscoelastic approaches based on MDPJ Bina Marga 2017 using the KENPAVE Program. The recommended design alternative is pavement with a layer of AC-WC 40 mm, AC-BC 60 mm, Base AC 180 mm, and LPA 300 mm. This alternative is predicted to be able to serve load repetitions in the elastic approach of 432,857,828 ESAL until fatigue cracking occurs, 215,176,089 ESAL until rutting occurs, and 136,575,580 ESAL until permanent deformation occurs. Analysis using the viscoelastic approach can provide load repetitions of 153,304,378 ESAL until fatigue cracking occurs, 47,014,109 ESAL until rutting occurs, and 71,859,938 ESAL until permanent deformation occurs. Based on the elastic approach, the pavement's service life is 33 years, with initial damage in the form of permanent deformation. In comparison, the viscoelastic approach has a service life of 22.7 years, with initial damage in the form of rutting.

Sustainable Reclaimed Asphalt Emulsified Granular Mixture for Pavement Base Stabilization: Prediction of Mechanical Behavior Based on Repeated Load Triaxial Tests

The stabilization of asphalt pavement bases with granular soil and aggregates emulsified with asphalt is a widely used technique in road construction and maintenance. It aims to improve the mechanical properties and durability of the lower pavement layers. Currently, there is no consensus on the most suitable method for designing emulsified granular aggregates with reclaimed asphalt pavement (RAP), as it is very complex. Therefore, the methodology is generally based on compliance with one or more volumetric or mechanical parameters established in the highway regulations for conventional asphalt mixtures, which does not guarantee the optimization and characterization of the recycled mixture in the base course. In this study, granular mixtures were developed, including five with emulsion and one emulsion-free as a control mix. Granular RAP mixes were designed in this study, including five with emulsion and one emulsion-free as a control mix. The five mixes ranged from 1% to 5% emulsion and were characterized by multi-stage triaxial tests with repeated load resilient modulus (RM) and permanent deformation (PD) to evaluate their mechanical behavior. The results showed that the mixes had RM values between 350 and 500 MPa, consistent with literature values. However, they showed similar levels of accumulated deformation to the control mix without RAP emulsion. The sample with 1 % RAP emulsion exhibited a satisfactory RM value and better performance in PD than the control mix (5 mm) and showed accumulated PD values of up to 4 mm. In contrast, the other samples exhibited deformations of up to 6 mm. In this study, the multi-stagge triaxial RM and PD tests were found to be an effective predictive method for characterizing the behavior of RAP materials in base courses, regardless of the types of admixtures contained. Multi-stage resilient modulus and PD tests can be considered as a predictive method for the behavior of milled material in base courses. They were able to provide initial data for interpreting the behavior of ETB mixtures.

Investigation of Permanent Deformation Behaviour of Subbase Layer Mixed with Non-Plastic Stone Dust of the Pavement

Investigation of Permanent Deformation Behaviour of Subbase Layer Mixed with Non-Plastic Stone Dust of the Pavement

A sustainable rapeseed oil-based bio-additive designed for hard asphalt binders: Performance, environmental, and economic assessment

The inherent properties of hard asphalt binder give it both mechanical and economic benefits, rendering it a naturally advantageous material for preventing permanent deformation at higher temperatures. However, its poor resistance to thermal and fatigue cracking limits its application in the paving industry. This study aimed to improve the low-temperature and fatigue performance of hard asphalt binders by using the newly developed vegetable oil-based sub-epoxidized rapeseed oil (SERO). Two SEROs with epoxidation degree of 49.1% and 98.1% were synthesized through an oxidation reaction, respectively. Subsequently, the microstructural characteristics of SEROs were examined by Fourier transform infrared spectroscopy (FTIR) and Hydrogen nuclear magnetic resonance tests. The anti-oxidative aging properties of SERO modified hard asphalt binders were investigated through the utilization of mass loss and aging index. Additionally, the comprehensive rheological properties of SERO modified hard asphalt binders were explored via dynamic shear rheometer and bending beam rheometer tests. Furthermore, the modification mechanism of SERO on hard asphalt binders was confirmed through the quantitative analysis using the FTIR test. The findings suggested the improvement in anti-volatilization and anti-oxidative aging performance of bio-modified hard asphalt binders, which was positively related to the epoxidation degree of SERO. A notable softening effect of SERO on the hard asphalt binders was observed, which enhanced their resistance to thermal and fatigue cracking at lower and intermediate temperatures. The epoxy groups within SERO engaged in ring-opening reactions, forming a new oxygen bridge bond by combining with the unsaturated double bond presented in the asphalt. Consequently, this process resulted in the formation of cross-linked structures within bio-modified hard asphalt binders, thereby enhancing the elasticity. Notably, this phenomenon was most conspicuous in the SERO-H modified 50# binder. Finally, the environmental and economic assessment of SERO modified hard asphalt binders were conducted by the techno-economic method and the emission factors technique. The data revealed that the production of one ton of SERO modified hard asphalt binders could reduce the production costs by about 30%, energy consumption and CO2 emissions by around 20% in contrast to styrene–butadiene–styrene block copolymer modified asphalt binders. Hence, the substantial economic and environmental advantages make SERO an attractive bio-renewable additive for sustainable pavements.

Insights into the mechanism of modification by self-assembling starch-based fatty acid esters that cause a pronounced time-dependent effect on asphalt hardness

Modifying and controlling the viscoelasticity of asphalt is a major challenge for maintaining and managing paved roads and extending their life. To date, asphalt has been modified with petroleum-based synthetic polymers, mainly to improve its resistance to permanent deformation. While, we are developing an asphalt modifier, 2,3,4,6-O-tetrapalmitoylated-1,5-anhydro-d-glucitol (C16AG), which is obtained from starch and fatty acids as raw materials. Here, we performed various experiments to obtain insights into the mechanism of asphalt modification by C16AG. The results showed that the hardness of C16AG-modified asphalt showed a time dependence: it remained softer than the original unmodified asphalt for several hours after the addition of C16AG and then hardened depending on the amount of C16AG added. The time dependence of the hardness of the C16AG-modified asphalt is related to the modification mechanism and it is proposed to include the following processes: (1) C16AG mixes with the resin and asphaltene that usually cause the hardening of asphalt and (2) prevents the ordering of these components; (3) then spontaneous fiber network is formed slowly by C16AG.

A Fully 3D-Printed Flexible Polymeric Heat Pipe

Abstract A fully 3D-printed polymeric heat pipe with high flexibility and low cost was demonstrated in this study. This wickless gravity-assisted heat pipe was fabricated using a commercial stereolithography 3D printer. The interconnected pocket array was designed to reduce the wall thickness to ∼0.1mm. The post-cured heat pipe can be flexed and twisted without tearing or permanent deformation. Experimental studies were conducted to characterize the performance of the heat pipe in vertical and 90° flexed configurations. In addition, visualization based on a high-speed camera was applied to study the boiling process inside the heat pipe. By charging with a compatible dielectric fluid HFE-7100, the present heat pipe achieved 18.6 W heat dissipation over a hot spot with an area of 25×25 mm2. The result showed an effective thermal conductivity of up to 102.7 W/(m·K) when placed vertically. The bubble dynamics and heat transfer data suggested little difference in performance between the vertical and flexed configuration after the startup of the heat pipe at 5.4 W, owing to a high charging mass. Last, a comparison of the present study and other reported fully polymeric flexible heat pipes was made, and future optimization of the heat pipe performance was discussed.

Ageing tests with high temperatures of prototype vibroacoustic isolators – under ballast mats (UBMs) based on recycled materials

This study focuses on experimental ageing tests with high temperatures carried out on prototype under ballast mats (UBMs) according to the procedure of the European standard EN 17282, which was introduced in late 2020. Most of the analysed UBM samples are based on recycled elastomeric materials, such as styrene-butadiene rubber (SBR) granules and fibres from end-of-life car tyres and rebond polyurethane waste from polyurethane product manufacturing plants. Additionally, two variations of the mat based on mineral wool are analysed. Significant differences in the values of static and dynamic characteristics measured before and after the ageing tests are demonstrated, and permanent deformations of the recycled polyurethane-based mats are shown. Moreover, it is proved that the elastomeric mats based on recycled rubber materials (SBR granules and fibres) have high durability and are an effective solution in terms of protection against vibration and structure-borne noise from railway traffic. In addition, the authors propose criteria for assessing the results of the ageing test with high temperatures of UBMs tested according to the procedure of EN 17282.

STRESS AND STRAIN ON STATE ROAD IB33 IN SERBIA

<p>In the pavement structure, stresses and deformations occur due to the effect of the environment and traffic load. The stresses that will occur mostly depend on the traffic load, the type of materials used, the modulus of elasticity of the materials used, the thickness of the layers... Due to the effect of the environment and traffic on the pavement, damage and the creation of permanent deformations, i.e. ruts, occur. If these damages are not repaired in time, the damage will develop even faster. In this paper, the traffic load on the road Požarevac - Veliko Gradište - Golubac was analyzed, the possible damage that may occur due to the effect of that load, as well as the method of maintaining that roadway in order to prevent major damage to the roadway structure.</p>

Undrained behavior of marine clay under one-way cyclic loading with variable confining pressure

Settlement of roads or railway caused by traffic loading has a serious effect on the safety and service performance of transport infrastructures constructed on soft marine clay. While simple cyclic triaxial test with constant confining pressure (CCP) were used in most of the previous studies, a series of cyclic triaxial tests with variable confining pressure (VCP) were carried out on normally consolidated (NC) and overconsolidated (OC) reconstituted Wenzhou soft clay in this paper to study the undrained behavior of soft marine clay due to surcharge preloading as well as cyclic traffic loading. VCP test is able to approximate the complicated stress path than CCP test caused by traffic loading. The test results indicate that NC specimens show significantly different pore water pressure (u) evolution compared with OC specimens. However, a change in the overconsolidation ratio (OCR) of OC specimens does not have a significant influence on variation of u with identical cyclic stress ratio (CSR) and total stress path (η). The slope of the effective stress path is dependent on the total stress path under which the specimen was loaded cyclically, regardless of the OCR and whether variable confining pressure was applied. The slope of the effective stress path is broadly in line with the slope of corresponding total stress path. In addition, the development of permanent axial strain (εpa) due to one-way cyclic loading was shown to depend significantly on the values of η and OCR. Both the variable confining pressure and OCR limited the strain accumulation of saturated marine clay under undrained one-way cyclic loading. Finally, the effects of η and OCR on the magnitude of εpa after 1000 loading cycles are quantified and incorporated in a power law function for the permanent deformation prediction of soft marine clay due to traffic loading.

Enhancing Porous Asphalt Performance by Adding Waste Mask Fiber: Experimental Analysis of Stiffness, Fatigue, and Creep at Optimum Asphalt Content

Purpose: This study aims to evaluate the impact of incorporating waste mask fibers into porous asphalt mixtures, focusing on stiffness, fatigue, and creep performance at the optimum asphalt content (OAC). Theoretical Reference: The study is based on sustainable construction and materials engineering theories, emphasizing the recycling of waste materials to enhance the performance of construction materials and mitigate environmental impacts. Method: Laboratory experiments were conducted by adding waste mask fibers at varying levels (0%, 1%, 2%, and 3% by weight of asphalt) to the porous asphalt mixtures. Test specimens were designed and evaluated for stability, flow, Marshall Quotient, Voids in Mineral Aggregate (VIM), indirect tensile strength (ITS), stiffness (ITSM), fatigue, and creep performance. Results and Conclusion: The addition of 1% waste mask fibers at the OAC is recommended as it meets the criteria for stability, flow, Marshall Quotient, and VIM. The Cantabro Test showed enhanced resistance, while the ITS Test indicated increased indirect tensile strength. The ITSM Test revealed heightened stiffness of the mixture. Although fatigue testing demonstrated that the porous asphalt mixture could bear loads until collapse at a certain stress level, the creep test confirmed the mixture's resistance to permanent deformation due to traffic loads. Implications of research: The findings suggest that incorporating waste mask fibers into asphalt mixtures can improve mechanical properties and durability, offering a sustainable solution for mask waste disposal. This approach can be adopted by policymakers and engineers to enhance road construction practices while addressing environmental concerns. Originality/value: This study provides novel insights into the recycling of waste mask fibers in asphalt mixtures, demonstrating their potential to improve performance and sustainability in road construction. The research offers a pioneering approach to addressing the environmental challenges.

Optimized characterization of the permanent deformation of unbound soils and granular materials considering the master curve concept

This paper presents a new method to evaluate the permanent deformation (PD) of soils and granular materials. Based on the concepts of shakedown and shift model, the PD analysis was proposed by means of master curves considering the initial 10,000 loading cycles of each applied stress state. Analogous to the superposition principle adopted in the construction of master curves for viscoelastic properties, the superposition loading cycle-magnitude of stress pair is proposed for the PD characterization of soils and granular materials. Thus, shift factors are used that provide the construction of master curves for each stress pair in an extended space of cycles. The master curves were used to predict the permanent deformation of soils and granular materials by increasing the number of cycles analyzed for each stress pair. For this, 24 different soils and granular materials were tested and analyzed to identify the influence of the loading cycles and stress state on the material behavior. The predictions provided by the proposed model were compared with those of another model currently used for flexible pavement design in Brazil. The results demonstrated the accuracy of the proposed methodology and indicated that it is possible to significantly reduce testing time than required for the PD characterization of soils and granular materials.