New Swedish Design Method for Concrete Pavements

The U.S. Federal Highway Administration (FHWA) hosted a ``Concrete Pavement Strategic Planning Meeting'' in August 2019 for the purposes of 1) identifying future needs and directions in concrete pavement design, and 2) the development of strategies to increase the implementation of long-life concrete pavement (LLCP) design and construction. The meeting was attended by an Expert Task Group (ETG) of knowledgeable concrete pavement experts and practitioners representing highway agencies, academia, industry partners and the Federal Highway Administration (FHWA). Many of the strengths and limitations of current concrete pavement design procedures were identified and discussed. It was recognized that AASHTOWare PavementME Design and other similarly sophisticated procedures represent a significant technological leap over empirical design procedures with which they compete (and often replace). However, there are concerns about performance model limitations, the cost-effectiveness of local calibration efforts, the emphasis on surface thickness design (often assuming, rather than designing, support conditions), and other issues. The potential service and economic benefits of LLCP were also discussed. The impetus for implementation (and benefits documented) by some agencies were described, as were the impediments to implementation for other agencies. Strategies were developed to help overcome the impediments identified and to facilitate broader use of LLCP. This paper summarizes key points raised on each of these issues and includes recommendations for future directions in concrete pavement design and increased implementation of LLCP.

Concrete pavements are the superstructure elements that can serve for a long time withoutdeterioration. Concrete pavements are using intensively for interstate highways where heavy traffic volume ishigh, parking facilities, airfields and industrial facilities. One of the most important features of concrete pavements,which are widely used in interstate roads in America, is more environmentally friendly compared to flexiblesuperstructures. This increases the need for concrete pavements in our time when sustainability is important.Because of the complex concrete properties and soil properties, the concrete pavement design is complex thanexpected. Due to the complexity of the designs, they were previously designed based on experiences. Subsequently,design methods with both mechanical and experimental infrastructure have been developed thanks to mechanicalmethods. Among these design methods, PCA 1984 and AASHTO 1993 are the most widely used for concretepavement design. Both the PCA 1984 and the AASHTO 1993 design method are used concrete properties, subgradereaction, and traffic characteristics as input parameters. In this study, three main parameters affecting concretepavement thickness (concrete properties, soil reaction and traffic) were examined according to AASHTO and PCAmethods. By this way, the correlation between pavement thickness and these parameters is shown. Another resultobtained from this study is which parameters are more sensitive to concrete pavement thickness.

Design of concrete pavements is carried out with the help of available guidelines that are generally based on single size of slab panel. However, in practice, the slab size is seen to be different than the one recommended by most of the guidelines such as PCA (Thickness design for concrete highway and street pavements, Portland Cement Assosiation, Skokie, 1984) and IRC 58 (Guidelines for the design of plain jointed rigid pavements for highways, 4th Revision, Indian Road Congress, New Delhi, 2015) , especially on curves or at the junctions. It is also established that temperature stresses vary with the plan size of the panel. The important parameter in the design of concrete pavement is critical edge stress which depends on traffic and temperature load. However, it is observed that, for the same design parameters such as traffic load and subgrade stiffness of soil, critical stress values alter largely as the panel size is diverse from the standard one. The standard panel size as specified by PCA (1984) and IRC 58 (2015) is 3.5 m $$\times $$ 4.5 m. In this paper, the effect of the size of slab panel and radius of relative stiffness on critical edge stress has been investigated. Analytical models have been developed to obtain critical edge stress for concrete pavement resting on an elastic soil foundation using finite element software. It has been found that, for smaller panel sizes with low radius of relative stiffness, critical stresses obtained are higher. Therefore, it is necessary to consider the effect of the size of slab panel and radius of relative stiffness, while designing the concrete pavement.

Contribution follows the previous work of authors in the field of implementation of objectified results of climate change in the design of roads, especially their pavement [1] to [3]. Climate conditions are besides traffic load, one of the permanent external factors adversely affecting the physical and mechanical properties of the construction layers. For designing concrete pavements is used in SR conditions average annual air temperature Tm and frost index for design of asphalt and concrete pavements. As part of the research activities carried out at the workplace, the authors statistically evaluated average daily temperatures of SR meteorological stations covering most of the SR territory with altitude from 115 to 695 m above sea level in the years 1971 to 2011. Act No. 135/1961 Coll. (Road Act) states that the design of road pavements is performed according to valid Slovak technical standards, technical regulations and objectively identified results of research and development for road infrastructure. On the basis of the presented correlations, it can be stated that the presented research results can be used immediately for SR conditions in the design of road pavements.

Analysis of shrinkage stress in concrete beam and some laboratory tests to verify this analysis were carried out. Deformation due to drying shrinkage and thermal cycles was measured in the field on model and full-sized concrete pavements (with and without expansive components) to obtain the distribution of shrinkage strain, the restraint by subgrade, the combined strain due to drying shrinkage and thermal cycles and the effects of use of expansive concrete on shrinkage stresses. Shrinkage stress in concrete pavements was evaluated by these observations and supplemental laboratory tests. The result shows that shrinkage stresses in concrete pavements due to drying shrinkage are by no means small, especially warping shrinkage stresses due to restraint of curvature of pavements should be considered in the design of concrete pavements.

Characterization of environmental loads related concrete pavement deflection behavior using Light Detection and Ranging technology

The AASHTO Mechanistic-Empirical (M-E) pavement design method offers cost-effective and sustainable design solutions for concrete pavements. However, its implementation is hindered by the complexity and time-consuming nature of the iterative computational process required to obtain optimal designs using the companion Pavement ME software. Furthermore, high license fees limit its wider adoption. Previous attempts to employ machine learning (ML) models for M-E design, instead, faced challenges in balancing model accuracy and capability with the increasing number of required training samples when including more design variables. Consequently, existing ML-based tools mainly focus on only a small subset of state or local designs. To address these limitations, this study introduces a novel sampling method called scalable adaptive sampling for the creation of efficient and accurate Artificial Neural Network (ANN) models capable of considering a wide range of pavement design variables with nationwide applicability. 40 representative climate stations were selected across the contiguous US. The ANN models were trained using adaptively generated samples from Pavement ME simulations. The developed ANN models exhibited high accuracy in predicting fatigue damage and differential energy, enabling the estimation of long-term transverse cracking and joint faulting performance, respectively. The developed ANN-based M-E design tool offers flexibility for considering multiple variables during pavement designs. It matches the accuracy and surpasses the computational speed of the Pavement ME. By overcoming the limitations of the conventional ML-based M-E implementation, this research contributes to advancing efficient and reliable concrete pavement design practices.

The State of Qatar is experiencing tremendous growth in infrastructure including road network and highways. The current methods used in design of asphalt pavements in the State of Qatar are empirical and might not be suitable for the design of long-lasting pavements. Given the significant increase in traffic, road authorities in the State of Qatar have been considering the use of mechanistic-empirical methods in the design and analysis of asphalt pavements. This study documents the results of a study in which the mechanistic-empirical pavement design guide (M-E PDG) software was used in the design of asphalt pavements with input parameters that were carefully selected to reresent local materials and climatic conditions. The selection of material properties was based primarily on specifications and design guides in the State of Qatar and on published literature about these materials. The mechanistic-empirical method was also used to assess the benefits of adopting the concepts of perpetual pavement design and also to compare the performance of pavement structures in which various bitumen grades, granular bases and chemically stabilised sub-base were used. A life-cycle cost analysis was carried out to determine the design with the highest net present value among the various options investigated. It is expected that the outcomes of this study would promote the use of mechanistic-empirical methods in the State of Qatar and the region. Inevitably, this will require significant efforts to calibrate material and damage prediction models used in the M-E PDG for more accurate representation of material properties and measured pavements performance.

Sustainable pavement design requires a balanced consideration of economic, environmental, and social impacts. In line with Federal Highway Administration (FHWA) guidelines for sustainable roadway infrastructure, incorporating recycled materials such as reclaimed asphalt pavement (RAP), recycled pavement material (RPM), recycled asphalt shingles (RASs), and warm-mix asphalt (WMA) has been shown to reduce natural resource depletion while promoting circular construction practices. This study investigates the structural performance of Portland cement concrete (PCC) pavements constructed on RAP and RPM base layers. A series of design scenarios was modeled using site-specific laboratory and field data—particularly subgrade soil properties and climatic conditions—from El Paso and San Antonio, Texas. The analysis incorporates unsaturated soil parameters and follows the performance thresholds set by the Mechanistic-Empirical Pavement Design Guide (MEPDG). Findings indicate that concrete mixture design, pavement structure, and local weather conditions are the primary drivers of distress in jointed plain concrete pavements (JPCPs). However, subsoil characteristics have a significant impact on joint faulting in JPCP and punchout occurrences in continuously reinforced concrete pavements (CRCPs), especially in thinner sections. Notably, the use of up to 50% recycled material in the base layer had minimal adverse effects on pavement performance, underscoring its viability as a sustainable design strategy for rigid pavements.

This research is highly urgent in bridging the knowledge gap between standard theory, field practice, and the dynamics of current industrial area development. The construction and periodic maintenance budget for asphalt road pavement with a duration of 20 years requires a cost of Rp. 17,638,200,000.00, then the construction and periodic maintenance budget for asphalt road pavement with a duration of 40 years requires a cost of Rp. 52,225,100,000.00. The construction and periodic maintenance budget for 20-year UR concrete road pavement requires a cost of Rp. 9,063,000,000.00, then the construction and periodic maintenance budget for 40-year UR concrete road pavement requires a cost of Rp. 15,031,400,000.00.

Faulting is a major and commonplace distress in jointed concrete pavement (JCP) that can directly cause pavement roughness and adversely influence the ride quality of a vehicle. Faulting also plays an essential role in concrete pavement design. Notwithstanding the importance of faulting, the accuracy and reasonability of the faulting prediction models that have been developed to date remain controversial. Furthermore, the process of faulting over time is still not fully understood. This paper proposes a novel mechanistic-empirical model to estimate faulting depth at joints in the wheel path in JCP. Two stages within the process of faulting were revealed by the model and are introduced in this study. To distinguish the two stages of faulting, an inflection point, as a critical faulting depth, was directly determined by this model and suggested to be an indicator of the initiation of erosion for concrete pavement design. The proposed model was proven accurate and reliable by using long-term pavement performance data. The parameters in the model were statistically calibrated with performance-related factors by Akaike’s Information Criterion for variable selection and performing stepwise regression.

Since corner breaks are one of the major structural distresses in jointed concrete pavements, this research study mainly focuses on the determination of the critical bending stresses at the corner of the slab due to the individual and combination effects of wheel loading and thermal curling. A well-known slab-on-grade finite element program (ILLI-SLAB) was used for the analysis. The structural response characteristics of a slab corner were first investigated. Based on the principles of dimensional analysis, the dominating mechanistic variables were carefully identified and verified. A series of finite element factorial runs over a wide range of pavement designs was carefully selected and conducted. The resulting ILLI-SLAB corner stresses were compared with the theoretical Westergaard solutions, and adjustment factors were introduced to account for this discrepancy. Prediction equations for stress adjustments were developed using a modern regression technique (Projection Pursuit Regression). A simplified stress analysis procedure was proposed and implemented in a user-friendly computer program (ILLISTRS) to facilitate instant stress estimations and practical trial applications.Key words: concrete (rigid) pavements, corner breaks, loading, thermal curling, corner stress.

The government of India has embarked on the construction of major highways with concrete pavements to eliminate frequent maintenance of bituminous pavement, damaged by heavy commercial vehicles and moisture. Hence, it is necessary to re-examine the current pavement design with a sound analytical approach. The current practice in the construction of concrete pavement in India is to place pavement quality concrete (PQC) over dry lean concrete (DLC) layer with a bond-breaking layer of 125-micron plastic sheets between the DLC and PQC layers to eliminate possible reflective cracks from the DLC to the PQC layer. Concrete pavement can be bonded to lean concrete (LC) when both layers are laid one after the other with two pavers (‘fresh-on-fresh’ or ‘wet-on-wet’). This type of pavement is also known as two-lift concrete pavement (TLCP), and such pavements were constructed in India during the last three years. No readymade solutions are available to compute stresses in such TLCPs. The objectives of the research are manifolds. Firstly, this article illustrates the analysis of Two-Lift Concrete Pavement (TLCP) using Finite element programming software (ANSYS) with an interface layer CONTA 174, which is able to capture interfacial stresses occurring between layers due to non-linear temperature gradient distributed over the depth of the slab. Then the design of pavements with TLCP has been introduced using the cumulative fatigue damage method. Finally, the cost of construction for TLCP is determined and compared with that of conventional concrete pavement. It was found that the material cost for TLCP is less than that of conventional concrete pavement because the stresses induced due to both load and environmental effects in TLCP are significantly lower when compared to those on the conventional concrete pavement.

In the article "Subgrade Soils: An Important Factor in Concrete Pavement Design" by Marshall R. Thompson and Barry J. Dempsey, the importance of subgrade soils in the design and performance of concrete pavements is thoroughly examined. The study elaborates on how subgrade conditions significantly impact the overall effectiveness and longevity of pavement systems, influencing not only the initial construction process but also the long-term operational stability. The paper discusses the critical influence of soil properties and climatic conditions on subgrade performance. Key factors such as water content, temperature, and soil composition (e.g., clay content and plasticity) are analyzed for their effects on the soil's strength and deformation properties. The resilience of subgrade soils under repetitive loads, known as the "resilient modulus," is highlighted as a vital parameter in assessing pavement durability and design adequacy. The research also explores the implications of environmental factors, emphasizing how moisture and temperature variations can drastically alter the physical properties of subgrade soils. It provides detailed insights into the methods for predicting these conditions and their integration into pavement design to enhance performance predictability. Overall, the article calls for a deeper understanding and more rigorous evaluation of subgrade soils in pavement engineering to ensure that designs are both effective in the short term and sustainable over the lifecycle of the pavement, considering the variable and often harsh environmental conditions these structures are subjected to. (Abstract generated by AI tool ChatGPT 4)

Based on the theory of layered elastic systems mechanics, the stress of asphalt concrete bridge deck pavement structure systems under the action of wheel-loads is obtained and the main influence factors are considered in this paper. The numerical results of a bridge over Chongyang Reservoir is carried out by using the commercial finite element software ANSYS. The effects of various thickness and modulus of upper layer and lower layer on the mechanical indexes of pavement are analyzed. The theoretical and numerical results indicate that among the considered factors the elastic modulus of upper layer is the most important influencing the magnitude of the stress of asphalt concrete bridge deck pavement structure. The obtained results is hoped to provide the theoretical guide for the design and construction of asphalt concrete bridge deck pavement.