Semi-rigid Pavement Research Articles

Machine learning modelling the rut depth of WMA mixtures with variable reclaimed asphalt pavement (RAP) and foamed bitumen content

ntroduction. Rutting of flexible, super flexible and semi-rigid pavement structures is a typical and frequently decisive condition parameter, form of pavement deterioration. That is why, any research result in the field can have of high importance for the road engineers. Problem Statement Rutting poses a significant challenge to asphalt pavements, causing permanent deformation under heavy loads, particularly in warm and wet conditions. Purpose. This pavement distress type has — in addition to riding comfort challenges — important traffic safety consequences (e.g. aquaplaning), as well. The research work concentrates on the influence of the use of warm mix asphalt, reclaimed asphalt material and foamed bitumen binder on the rut depth of asphalt pavements.

Evaluation of grouting effectiveness for Semi-Rigid pavement base layer cracks based on Time-Frequency domain signal characteristics of 3D GPR

This study aims to address the deficiency of rapid, comprehensive, and non-destructive methods for evaluating the effectiveness of grouting treatment on semi-rigid pavement base layer cracks. By integrating radar simulation with empirical measurements, we establish a comprehensive evaluation method for the grouting treatment effectiveness of pavement base layer cracks. Initially, we propose a GprMax simulation of crack models with varying grout-filled volumes, analyzing the time–frequency domain signal characteristics before and after grouting. Based on data sensitivity, thirteen time–frequency domain signal characteristics are selected as grading evaluation indicators. Subsequently, relying on an engineering case study, we conduct a graded evaluation of the grouting effect on base layer cracks, analyzing the correlation and weight of evaluation indicators to derive a comprehensive evaluation method. Field coring results confirm the accuracy of the comprehensive graded evaluation method.

Development of sustainable interlocking concrete paving blocks using bamboo leaf ash and metakaolin

Eco-friendly interlocking concrete pavement block was developed using the admixture of bamboo leaf ash and metakaolin. This was done to develop an eco-friendly interlocking paving block for sustainable pavement construction. Bamboo leaf ash and metakaolin were added as a supplementary cementitious material. The supplementary cementitious material (bamboo leaf ash and metakaolin) were admixed and added at 0, 5, 10, 15, 20, 25 and 30 % replacement of cement. The workability of the fresh concrete (slump) at the varied percentage additions, and the mechanical properties of the concrete at 7, 14, 28, and 56 days of curing were assessed, including their microstructural characteristics. The outcome of the research showed that increasing the percentage of (bamboo leaf ash + metakaolin) reduces the workability of the concrete. With a 20 % addition of this cementitious material, the developed fresh concrete became unworkable. In addition, replacing up to 10 % of the concrete in the pavement with bamboo leaf ash and metakaolin increased the mechanical strength of the concrete by 28.7 %. At 30 % a percentage increase of 3.6 % was recorded. However, the strength at 5 % was still adequate for pavement construction with a 13.62 % increase in mechanical strength. The compressive strength at 5 % and 10 % addition of the supplementary cementitious material at maturity met the criteria for constructing a semi-rigid pavement, using IRC standards. The microstructural assessment showed that the number of pores in the mature concrete samples decreased at 10 % addition of bamboo leaf ash and metakaolin. The research data provides construction workers, researchers, and highway engineers with vital information regarding the viability of these sustainable materials for pavement improvement.

Predicting the Performance of Semi-Rigid Pavement with Partial Replacement of RAP in RCC and Designed Using a Mechanistic–Empirical Method

Predicting the Performance of Semi-Rigid Pavement with Partial Replacement of RAP in RCC and Designed Using a Mechanistic–Empirical Method

Application of machine learning techniques to predict the temperature distribution in semi-rigid pavement with a cement-treated base

Application of machine learning techniques to predict the temperature distribution in semi-rigid pavement with a cement-treated base

Mechanics and road performance of mudstone modified stabilized gravel subgrade in arid desert areas

This study investigates the feasibility of using mudstone to enhance poorly graded gravel in certain arid regions of the S21 Altay-Urumqi Highway project in Xinjiang. Despite mudstone typically being considered a poor-quality rock, its combination with higher-performance materials like cement, lime, and fly ash can stabilize expansive soils for use as roadbed fill. In the experiments, 30% and 40% mudstone were added to the gravel mixture. The experiments were compared with unmodified K80 and 35% crushed rock mixes. The findings reveal that adding 30% mudstone substantially increased the California Bearing Ratio (CBR) of the gravel mix by over 20%. However, excessive mudstone inclusion could weaken load-bearing capacity. Moreover, mudstone-modified specimens exhibited superior unconfined compressive strength (UCS), splitting strength, compressive resilience modulus (CRM), drying shrinkage resistance, and temperature shrinkage resistance. Under optimum cement dosage, the UCS of mudstone-modified specimens outperformed unmodified specimens, consistently surpassing fly ash-altered groups. Although mixed fly ash initially exhibited lower strength, it gradually approached cement-stabilized strength with an extended curing time. Incorporating crushed stone into the grading curve significantly increased splitting strength due to its high strength and hardness. In contrast, adding mudstone introduced a notable proportion of fine aggregates, resulting in a looser grading skeleton prone to early cracking. This research demonstrates that mudstone enhancement significantly improves roadbed performance, including increased CBR, splitting strength, and crack resistance. The use of mudstone in arid desert areas enhances overall performance while reducing shrinkage coefficients. The suggested approach for semi-rigid pavements in arid deserts recommends specific mineral proportions, various aggregate sizes, an appropriate amount of cement, and 30% mudstone to create dense structures with a higher quantity of coarse aggregate.

Permanent Deformation Evaluation and Instability Prediction of Semi-rigid Pavement Structure Using Accelerated Pavement Testing and Finite Element Method

Abstract A rutting prediction method for semi-rigid pavement structures using accelerated loading tests and finite element analysis was proposed in this study. Firstly, dynamic modulus and creep tests of three pavement materials were performed by changing sizes and temperatures. The prediction equation was obtained and verified using the falling weight deflectometer test and back-calculation modulus, and it was coupled into a modified Burgers model for rutting simulation for full-scale pavement structures. Results showed that the dynamic modulus of pavement materials increased with increasing specimen sizes and decreased with increasing temperature. SUP-25 had an enormous fatigue damage value (0.419) after 5,400 times repeated loading. The error between the rutting simulation and test results was 2.87 %, indicating that the model effectively applies to multilayer composite materials. Rutting deformation at one million loading times in summer was 4.6 times that in winter. From 22 to 120 km/h, rutting deformation decreased by 72.6 %. Axle load increased by 100 %, and rutting depth increased by 46.9 %, indicating that vehicle overload should be restricted, especially in low-speed sections in high-temperature areas. Rutting deformation entered the accelerated accumulation stage when the cumulative action times were more than 25 million, which requires timely maintenance and repair of pavement structures.

Parametric characterization of semi-rigid asphalt skeleton using recycled materials

Concrete Pavement with significantly good resistance to wear and tear is expensive while asphalt pavement can easily be constructed and repaired but is not durable. In considerations to cost-benefit, modification in pavement construction plays a vibrant role. Exploration in semi-rigid pavement construction is getting common. This paper signifies the viable solutions of similar pavement using recycled materials. The methodology is based on detailed analysis of laboratory experimentations within the combinations of fresh aggregates, Reclaimed Asphalt Pavement (RAP) and Construction waste (CW). Focusing blend grading, clear differences are obtained between the stabilities of grouted and un-grouted samples. Likewise in the case of 100% RAP with minimum air voids and curing time, about 300% increase in stability observed in grouted sample. The paper corresponds to save the cost of 100% fresh aggregates identifying the need of the research. Possible combinations of RAP and CW reveal the passing of certain limits through grouting.

Utilization of rubber aggregates in cement-treated bases: A review

Cement-treated bases are commonly used in high-classified road pavements due to their stable strength and improved durability. However, this type of pavement base is sensitive to shrinkage caused by early water loss or temperature change after construction, resulting in shrinkage cracks and subsequent reflective cracking in semi-rigid pavements. To address this issue, various waste or by-products, such as oil, steel slag, end-of-life tires etc., have been investigated for use as an additive or a replacement for aggregates in cement-treated base. This review focuses specifically on the impact of rubber aggregates on the properties of rubberized cement-stabilized aggregates. In general, rubber aggregates are detrimental to the mechanical properties of cement-treated aggregates. However, the rubberized cement-stabilized aggregates exhibited reduced shrinkage and improved shrinkage cracking resistance, as confirmed through actual field applications. Furthermore, internal microstructure analyses indicate that rubberized cement-stabilized aggregates possess excellent anti-cracking capacity, particularly when subjected to compressive loadings. The review ends with recommendations and future studies to promote the applicability of rubberised cement-stabilized bases in semi-rigid pavements.

A hybrid approach for fatigue life prediction of in-service asphalt pavement.

Fatigue cracking is one of the main pavement failures, which makes accurate fatigue life prediction forthe design and maintenance of asphalt pavements crucial. The majority of traditional prediction methods are based entirely on the laboratory fatigue test, without considering the field condition and maintenance data. This paper aims to propose a hybrid approach to fill this gap. The key idea is that the damage condition isback-calculated by anartificial intelligence-based finite-element (FE) model updating using field-monitoring information (data-driven component), which is used to update the parameters in themechanistic composition-specific fatigue life prediction equation (model-driven component). The laboratory test of field cores gives the material non-destructive properties. The simulated pavement response subjected to truck loading shows good agreement with measured values, which indicates that the verified constitutive relationship could be used in the data-driven component. Furthermore, in view that the fatigue test is time- and money-consuming, this paper proposes a non-test estimation of thefatigue characteristic curve based on FE simulation of arepeated direct tension test. Three test pavement sections were employed as case studies. Results showed that the predicted fatigue life changes with the service time. At the early age, semi-rigid pavement has alarger fatigue life than flexible and inverted pavements. This article is part of the theme issue 'Artificial intelligence in failure analysis of transportation infrastructure and materials'.

Study on the dynamic response characteristics of roadbed and pavement under the humidity and season factors in the hilly area of Southwest China

The environment of the roadbed and pavement often has a significant impact on its dynamic performance. The stability of the strata in the Hilly Area is poor, and long-term complex environmental impacts will cause significant damage to the pavement. This article tests the dynamic response characteristics of semi rigid and inverted asphalt pavement through road load tests, and measures the humidity data of the roadbed during on-site rainfall. In addition, the variation of pore water pressure in the transition layer under the coupling effect of humidity and dynamic load was analyzed, revealing the influence of seasonal factors on the dynamic response of the pavement and roadbed. The test results indicate that the humidity inside the roadbed is greatly influenced by seasonal factors, and the humidity conditions of the roadbed and pavement vary significantly due to differences in measurement point depth, season, and rainfall. Graded crushed stone cushion is beneficial for improving the humidity conditions of the roadbed. The pore water pressure of the graded crushed stone transition layer did not show significant pore water reabsorption throughout the entire loading process. Meanwhile, the thickness of the surface layer and the magnitude of the load have a significant impact on the measurement of pore water pressure in the transition layer. The measured values of the dynamic response indicators of the pavement are greatly influenced by seasonal factors. The research in this article will provide theoretical and guiding significance for the dynamic response characteristics of pavement under the influence of multiple factors in the southwestern hilly area.

Rubberized cement-stabilized aggregates: Mechanical performance, thermal properties, and effect on temperature fluctuation in road pavements

Temperature change is one of the critical issues causing shrinkage cracking in cement-treated bases. This study aimed to evaluate the effect of incorporating rubber aggregates into cement-stabilized aggregate on temperature fluctuation in semi-rigid pavements. To estimate temperature change, the thermal property test was firstly conducted on rubberized cement-stabilized aggregates, in which the aggregate component (0.425 mm to 9.5 mm) was replaced by rubber aggregates (3–6 mm) at varying volume percentages of 0%, 5%, 10%, and 20%. The experimental results showed that increasing rubber aggregate content reduced the thermal diffusivity, thermal conductivity, and specific heat capacity of the rubberized cement-stabilized base materials. A good correlation between the thermal properties and surface temperature was also observed. These obtained thermal properties were then used in numerical simulations using the ANSYS program. The modelling results demonstrated the potential of rubberized cement-stabilized aggregates in reducing both temperature and temperature fluctuation within semi-rigid pavement structures. Furthermore, despite the detrimental impacts of rubber aggregates on compressive and splitting tensile strengths and compressive resilient modulus, the rubberized cement-stabilized aggregates still met the requirements for pavement bases.

Rutting prediction of asphalt pavement with semi-rigid base: Numerical modeling on laboratory to accelerated pavement testing

Rutting development and its prediction are critically important for the long-term preservation of semi-rigid pavements. A multi-scale test was developed to analyze the rutting development and its prediction model, involving triaxial, scaled loading, and full-scale loading tests. Laboratory-based triaxial tests predicted the rheological properties of asphalt mixtures at high temperatures. The flow number FN was only related to the cohesion and internal friction angle, confining pressure, and circulating pressure of the mixture. Rutting prediction models were established using a modified Burgers finite-element model and verified through scaled and full-scale loading tests. The relationship between FN of the dynamic creep test and loading times of scaled and full-scale loading test were determined through comparative analysis. Finally, the cross-scale relationship between the multi-scale tests was established by introducing correction coefficients K1 and K2. The proposed prediction model of rutting development is suggested to be computationally reasonable, which could provide a scientific reference for the treatment and maintenance of rutting on asphalt pavements.

Structural Performance of Foamed Asphalt Base in a Full Depth Reclaimed and Sustainable Pavement

Environmental awareness and budgetary constraints in road construction and rehabilitation require innovative and at the same time environmentally friendly solutions in favor of resource conservation, in any type of pavement intervention. In the meantime, surface interventions in severely deteriorated pavements are insufficient, increasing as such the recycling potential of existing materials in Full Depth Reclamation (FDR). This study addresses the efficiency of an FDR process in which the recycled base course of an existing semi-rigid pavement is stabilized with Foamed Asphalt (FA). The adverse effects of FA curing, which have a significant impact on pavement evaluation, particularly in the early stages of a pavement’s life cycle, prompted the conduct of a comprehensive testing campaign at two different periods, shortly after pavement rehabilitation and five years thereafter. The campaign included nondestructive testing at the aforementioned periods using Ground Penetrating Radar (GPR) and the Falling Weight Deflectometer (FWD), which facilitate the structural evaluation of the FA base. Using the collected nondestructive testing data, the principles of Multi-Layer Elastic Theory (MLET) and Genetic Algorithms (GA) are used to investigate the performance of the FA base. Both analysis tools captured the FA strength increase in the second period, but an increased variance of the FA modulus was observed mainly in the first test period, probably due to the curing effect. In addition, GA showed an advantage over other, more conventional tools for back-analysis of pavement stiffness, resulting in an interesting correlation potential of FA modulus to a deflection-based parameter reflecting the condition of the FA layer. Overall, the study contributes to the development of a practical methodology suitable for the evaluation of non-conventional and sustainable pavement structures.

Temperature-related thermal properties of paving materials: experimental analysis and effect on thermal distribution in semi-rigid pavement

ABSTRACT Thermal properties of paving materials are essential for estimating temperature distribution in semi-rigid pavements. Literature reported that the thermal parameters varied widely and were most independent of temperature. This paper proposed an innovative test setup to determine the thermal conductivity and diffusivity of hot mix asphalt (HMA) and cement-treated base (CTB) materials. The experimental results indicated that the thermal properties of the paving materials linearly increased with surface temperature. Field temperature monitoring in semi-rigid pavement was also conducted at different depths of HMA and CTB. The heating rate of any location inside the pavement was found approximately twice the heat release. Such obtained thermal parameters and the pavement surface temperature from field monitoring served as inputs for numerical simulations based on ANSYS programme. Using temperature-related thermal properties in the modelling exhibited higher accuracy in predicting temperature distribution in the semi-rigid pavement than those independent of temperature from the literature.

Modeling temperature profile of asphalt mixture in semi-rigid pavement

This study aims to investigate the extreme temperature variations of asphalt pavement structures. First, this study established a thermal analysis model using finite element methods to investigate the temperature profile of asphalt pavements. Thereafter, the significant factors affecting the pavement temperature were determined using the grey correlation method. Finally, linear prediction models for maximum, minimum, and average temperatures of asphalt layers at any depth were developed. The results indicated that the pavement and air temperature change trends were similar, and that the temperature decreased with increasing depth. The maximum temperature occurred on the road surface during the daytime and moved from the asphalt layer to the base layer during the night. The maximum temperature difference on the road surface was 26.8 °C. The most significant factors affecting the asphalt pavement temperature were air temperature and solar radiation. The maximum, minimum, and average temperatures of the asphalt layers had good linear relationships with air temperature, solar radiation, and depth of concern, and the R 2 of these predicted models were all greater than 0.94. In addition, a comparison between the predicted and actual measured pavement temperature of Beijing’s RIOHTRACK road in 2019 found that the R 2 between the measured and predicted values was greater than 0.90 and the root-mean-squared error was less than 5 °C. Using this model, the maximum, minimum, and average temperatures of the asphalt layer at any depth can be determined if the air temperature is known. These results will be beneficial for analyzing the stresses and strains resulting from temperature differences and calibrating the structural design methods for asphalt pavements.

Effect of basalt fiber on properties of asphalt and asphalt mixture

Asphalt mixture is the surface material of flexible pavement and semi-rigid pavement. It directly bears the influence of climate conditions and traffic load, and is prone to aging and fatigue damage. Therefore, using reinforcing agent to improve the performance of asphalt mixture is the long-term goal of researchers.This paper aims to study the effect of basalt fiber on asphalt viscosity and mechanical properties of asphalt mixture. Firstly, by testing the basic properties of asphalt binder with different fiber content, the viscosity characteristics of fiber + asphalt composites are analyzed by using the modified Einstein viscosity equation. The research shows that basalt fiber has obvious toughening effect on asphalt, and the penetration and softening point indexes are suitable to evaluate the viscosity properties of fiber + asphalt composites.Secondly, the effects of different fiber content on the water stability and splitting tensile strength of asphalt mixture are analyzed. The results show that the maximum content of basalt fiber should not be greater than 0.4%; With the increase of fiber content, the splitting strength of asphalt mixture increases, but the increase is not obvious when the content is > 0.30%, while the stiffness modulus continues to increase, indicating that the deformation resistance of asphalt mixture is enhanced after adding fiber. Based on the micromechanics theory of composite materials, the basic principle of basalt mineral fiber improving the strength performance of asphalt mixture is explained. The research shows that basalt mineral fiber can significantly improve the performance of asphalt mixture.

Calculation and Analysis of Load Stress on Typical Semirigid Base Asphalt Pavement

The linear elastic Bisar software was used to calculate the mechanical properties of a typical semirigid pavement structure. Based on the concept of structural strength coefficient, the fatigue life of each pavement structure layer was deduced. The results show that: (1) the maximum value of deflection was obtained at x=3r/2, the maximum of the surface stress was obtained at X=r/2 and Y=0, and the peak of the principal shear stress at the bottom. (2) At the same time, the horizontal load, road surface deflection, and the maximum stress position of the surfacing surface are invariably applied at the same time. The deflection changes little, and the maximum principal stress increases faster than the maximum shear stress. (3) The cracking order of the structural layer is as follows: shear cracking of surface layer to bending and cracking of surface layer to bending and cracking at the bottom of base layer to bending and cracking at the bottom of semirigid base to bending and cracking at the bottom of the surface layer. The inner edge of a single circle is the destroying source of asphalt pavement, and the initial damage is shear bending failure. Therefore, the durable pavement should consider the principle of structural layer cracking from bottom to top and to prevent the early destruction of the surface layer. (4) The cracking of the base layer will be reflected to the semirigid base and surface layer, which is the first step of structural damage, so strengthening the construction quality of the subbase is an important measure to reduce road damage.

Study on the dense structure and properties of cement-stabilized coral aggregates

The performance of cement stabilized coral aggregates semi-rigid base of pavement with coral reef limestone fragments and biological debris as the main materials is essential in the current reef engineering constructions. The performance of inorganic mixtures such as cement-stabilized coral aggregates mainly depends on the packing state of aggregates and the interfacial bonding among each component. Via digital image analysis theory, a simulation model of the dense packing of particles method was established, considering the influence of arbitrary particles shape distribution, upper limit of particles size, and aggregates gradation. The influencing mechanism of different factors on the packing state was revealed. It was found that the dense packing of coral aggregates is a strong suspension dense structure which did not form the skeleton structure. The strengthening mechanism of the coral particle-coated cement slurry was studied through the experimental analysis of the pore structure of coral rocks and debris particles and the crushing strength of particle-coated cement slurry, combined with the microhardness test of the cement- coral particle interface and the analysis of hydration products. The physicochemical excitation mechanism of hydration products densification，“physical interlocking” and “micro pump” effect at the interface of the cement-coral particle was revealed. Furthermore, based on the macroscopic mechanical properties of cement stabilized coral aggregates, the optimal design ratio of coral aggregates with upper limit particle size of 53mm, fine aggregates content of 45% and cement content of 8% was proposed. The findings of this study can provide a reference for the design and application of cement stabilized coral aggregates semi-rigid pavement base.

Study on Vehicle–Road Interaction for Autonomous Driving

Autonomous vehicles (AVs) are becoming increasingly popular, and this can potentially affect road performance. Road performance also influences driving comfort and safety for AVs. In this study, the influence of changes in traffic volume and wheel track distribution caused by AVs on the rutting distress of asphalt pavement was investigated through finite element simulations. A vehicle-mounted three-dimensional laser profiler was used to obtain pavement roughness and texture information. The vehicle vibration acceleration was obtained through vehicle dynamics simulations, and the skid resistance indexes of 20 rutting specimens were collected. The results showed that an increase in traffic volume caused by the increasing AV traffic accelerated the occurrence of rutting distress; however, the uniform distribution of vehicles at both ends of the transverse direction could prolong the maintenance life of flexible and semi-rigid pavements by 0.041 and 0.530 years, respectively. According to Carsim and Trucksim vehicle simulations and multiple linear regression fitting, the relationship models of three factors, namely speed, road roughness, and comfort, showed high fitting accuracies; however, there were some differences among the models. Among the texture indexes, the arithmetic mean’s height (Ra) had the greatest influence on the tire–road friction coefficient; Ra greatly influenced the safe driving of AVs. The findings of this study were used to present a speed control strategy for AVs based on the roughness and texture index for ensuring comfort and safety during automatic driving.