Pavement Construction Research Articles

Comparative Analysis of Rubberized Asphalt and Traditional Asphalt: Performance, Economic, and Environmental Impacts in Life Cycle

Rubberized asphalt mixtures, including dry-process, wet-process with asphalt rubber binder, and wet-process with terminal blend binder, are superior options for pavement construction compared to conventional hot mix asphalt (HMA). This study compared these mixtures in terms of performance, cost, and environmental impact, considering their expected lifespan. Their performances were assessed through a literature review, the costs for material production and construction were estimated, and the environmental impacts were evaluated using a life cycle assessment (LCA) with the SimaPro software. The results showed that rubberized mixtures, overall, outperformed conventional asphalt by about 25%, making them a viable choice for sustainable pavements. Despite the higher material and construction costs, an economic analysis revealed that rubberized mixtures are more cost-effective in the long term due to their extended service lives. The wet-process rubberized mixture made with asphalt rubber binder proved to be the most cost-effective over the pavement’s lifespan, followed by the terminal blend and dry-process mixtures. The LCA indicated higher environmental impacts during production for rubberized asphalt due to increased fuel consumption and material usage. However, when normalizing emissions over the pavement’s lifespan, the wet-process rubberized mixtures made with asphalt rubber binder exhibit the lowest equivalent CO2 emissions per year, making them the most sustainable option. The comparative approach used in this study highlights the pros and cons of rubberized asphalt mixtures, offering valuable insights for informed decision-making in pavement construction.

Evaluation of performance and statistical analysis of rigid pavement incorporating recycled aggregate concrete through the BBD methodology

Abstract The incorporation of recycled concrete aggregate (RCA) in the construction of rigid pavements has attracted considerable interest due to its environmental and economic benefits. A statistical method known as Response Surface Methodology (RSM) serves as an effective tool for optimizing concrete mix designs by adjusting independent variables to achieve desired characteristics. However, there is a lack of extensive research that combines modified mix designs with statistical modeling to predict the mechanical properties of concrete. Furthermore, many existing studies fail to consider the combined impacts of various factors, including cement content, water-to-cement ratio, and fine-to-coarse aggregate ratio, on the performance of concrete mixtures. This study aims to develop and optimize concrete mixtures that incorporate RCA for rigid pavements using the Box-Behnken Design method. The main goals were to forecast water absorption, compressive strength, flexural strength, split tensile strength, and slump of fiber-reinforced concrete, as well as to identify optimal mix designs that fulfill specific strength requirements. A total of 30 mixtures were tested, varying in four factors: cement content (300, 350, and 400 kg/m³), water/cementitious ratios (0.3, 0.4, and 0.5), fine/coarse aggregate ratios (0.3, 0.4, and 0.5), and silica fume content (0%, 5%, and 10% by weight of cement). RSM was employed to create predictive equations for the mechanical properties of the concrete mixtures, revealing that cement content and silica fume ratios had a significant impact on these properties, followed by the fine-to-coarse aggregate and water-to-cementitious ratios. The correlation coefficients (R²) for all predictive models exceeded 0.95, indicating a strong relationship between the independent variables and the mechanical properties. The optimal mix identified for achieving a compressive strength greater than 30 MPa and a flexural strength exceeding 4.1 MPa consisted of 365 kg/m³ of cement.

Application of Machine Learning in Estimating California Bearing Ratio from Soil Index Properties in Kenya

The California Bearing Ratio (CBR) is an important civil and transportation engineering test. It is normally carried out to assess soil's bearing capacity and strength for road pavement and foundation construction. The test, however, is both time-consuming and labour-intensive, resulting in significant delays during the construction process, ultimately leading to financial losses due to the high cost typically associated with construction projects. As a potential solution to this issue, an investigation is conducted into the application of artificial intelligence (AI) and machine learning (ML) techniques for accurately forecasting CBR values. Three models were used in the study, namely, the random forest model, linear regression model, and extreme gradient boosting (XGBoost) model. These models were employed to forecast CBR values based on several soil index properties. These properties included particle size distribution (i.e., percentage of soil passing through the sieve of diameter 0.425mm and 0.075mm), liquid limit (LL), plasticity index (PI), maximum dry density (MDD), plastic limit (PL), and optimum moisture content (OMC). A dataset containing these soil properties and corresponding CBR values for soils was obtained from the University of Nairobi civil engineering laboratory. The models were then trained on 80% of the data and tested on 20%. Mean Absolute Error (MAE), Mean Squared Error (MSE), Root Mean Squared Error (RMSE), and Coefficient of determination (R²) were used to evaluate the accuracy of the predictions. The findings showed that XGBoost was the most accurate model with the lowest MAE, MSE, and RMSE, and the highest R², making it the preferred model for predicting CBR

Ascertaining the Environmental Advantages of Pavement Designs Incorporating Recycled Content through a Parametric and Probabilistic Approach.

Reclaimed asphalt pavement (RAP) is a widely used end-of-life (EoL) material in asphalt pavements to increase the material circularity. However, the performance loss due to using RAP in the asphalt binder layer often requires a thicker layer, leading to additional material usage, energy consumption, and transportation effort. In this study, we developed a parametric and probabilistic life cycle assessment (LCA) framework to robustly compare various pavement designs incorporating recycled materials. Our framework is built upon thermodynamic and physical principles to reveal the complex relationship among the parameters. Mechanistic-Empirical Pavement Design Guide (MEPDG) models and Highway Development Management (HDM4) models are integrated into the framework to estimate pavement roughness and vehicle fuel consumption during the use phase. The pedigree approach and Monte Carlo simulation are integrated into the framework to reflect data uncertainty at the parameter level. We applied the framework to evaluate 66 Flemish motorway segments, revealing that using RAP in the binder layer with increased thickness does not necessarily guarantee lower greenhouse gas (GHG) emissions for pavement construction. However, it may lead to lower GHG emissions due to fuel savings when considering the use phase, highlighting the vital role of the use phase in pavement LCA. Our global sensitivity analysis highlights several contributors (out of 87 parameters) to GHG emissions variance depending on the LCA scope: fuel consumption during the use phase, transport distances, mass of fine aggregate, and machine power and machine productivity during pavement construction. Reducing uncertainties in these parameters can decrease the variance by up to 60%, enhancing discernibility by up to 11%. In conclusion, our parametric and probabilistic LCA framework provides a nuanced understanding when comparing various pavement designs incorporating recycled content, enabling robust decision-making through improved data quality.

Challenges with Construction of Portland Cement Concrete Pavement at Calgary International Airport

In preparation for construction of a parallel runway at the Calgary International Airport in the spring of 2011, concrete pavement had to be constructed to realign Gates A1–A10. Concrete mixes were developed for central batch production for both paver and hand placement methods. In addition, winter conditions required concrete delivery from a local concrete ready-mix supplier. The construction schedule required the paved sections to be open to aircraft traffic three weeks after pavement construction. A maturity method was developed to estimate early age compressive/flexural strength of the concrete pavement. This paper presents the process utilized in developing the concrete mix design to meet the project requirements for Cement Stabilized Base (CSB) and the Portland cement concrete mix, the development of the plant mix, and the construction methodology. Additional challenges with pavement construction in winter conditions are highlighted, including CSB and concrete placement, curing conditions, control joint construction, and instrumentation for maturity of concrete determination. The verification process for final acceptance of the product is described, including durability testing and pavement design review. This project demonstrated that concrete pavement can be constructed under accelerated schedule and during adverse weather conditions with the quality of the pavement not compromised and the construction schedule successfully managed.

Construction of a Cement Concrete Pavement in a Hilly Terrain in India

The National Highway No 48 is an important artery connecting the capital city of Bangalore and the coastal city of Mangalore in the state of Karnataka in India.Over 5000 heavily loaded commercial vehicles per day with single and tandem axle loads as high as 200 kN and 400 kN respectively form bulk of the traffic. The highway alignment passes throughan eco-sensitive area with topography having steep longitudinalgradients up to 6%, and temperaturesfrom 16°Cto 36°C. The road has 152curvesin a length of 26 km with a large number of acute angled curves on gradients. The existing Asphalt Concrete pavement needed continuous maintenance due to heavy rain. It was decided to rehabilitate it with a jointed cement concrete pavement overlaid on a subbase of Roller Compacted Concrete (RCC) of10 MPa strength. The Paper gives highlights of design and construction of Dowel Jointed Cement Concrete Pavement having an8.50-meter wide carriageway constructed in two halves because of space constraints. Intercepting water by means of nonwoven geotextile and open graded aggregate due to the artesian condition owing to high water table was an important feature of the project.

Investigation of Curling and Warping on US 34 near Greeley, Colorado

Construction of a jointed concrete pavement on US 34 near Greeley, Colorado in 2012 led to an investigation of slab curling and warping that appeared to be contributing to undesirable levels of pavement roughness. The Colorado Department of Transportation (CDOT) initiated an investigation to quantify the effects of slab curling and warping on ride quality for the US 34 project and to identify possible changes in construction practices to mitigate the effects of slab curling on future projects. This paper summarizes the various analyses that were conducted under this research project and the results from this investigation. It also provides recommendations for improvements in construction practices to help minimize jointed concrete pavement slab curling and warping and recommendations for the collection of smoothness acceptance data such that the effects of curling and warping can be captured.

Experiences Resulted from Construction of Two-way Post-Tensioned Concrete Pavement

In this paper there are presented results of experimental investigation and preliminary conclusions dealing with the efficiency of early posttensioning concrete pavement. Short section of concrete pavement 3.5 by 20.0 m (11.5 by 65.6 ft) thickness 0.23 m (9 in.) was posttensioned in longitudinal and transverse direction. The total prestressing was realized in one stage after 48 hours from concreting. The unbonded tendons 75 mm (0.6 in.) were tensioned with 200 kN (45 kip) force in both direction. The aim of investigation was the experimental evaluation of temperature and concrete strains distributions during the process of pavement concrete hardening for different environmental condition for period of 13 months. Values of prestressing force distribution were monitoring for 26 days period. For this reason, unbonded tendons were equipped with vibrating wire force transducer Geokon type. The concrete strains as well as temperature changes were recorded with Geokon vibrating wire sensors localized at three levels of the slab thickness in four vertical cross-section.

NEED BASED ADVANCEMENTS IN MAKING CONCRETE PAVEMENTS

Presently, innovations in concrete pavements are completely changing its design and construction. New-age concrete of compressive strengths more than 200 MPa also has very high tensile strength with or without the inclusion of steel/ synthetic structural fibers. Similar types of concrete mix proportions are referred in IRC: SP: 83-2008 under “Early Opening to Traffic” (EOT) concrete pavements, for maintenance of rigid pavement. Among other special concrete, Self-Consolidating Concrete (SCC) eliminates the need of mechanical consolidation and electrical energy at site and yields a required surface finish without segregation and undulation. Recently, it has been recommended in IRC:SP-62-2014 for construction of low volume concrete pavements in villages where skilled labour and mechanical/ electrical energy may not be easily available. Other similar technologies which are cost effective and environment friendly are given as under: i) Recycled concrete pavements, ii) Roller compacted concrete pavements (IRC:68-2005), iii) Ultra high performance concrete pavements(IRC:SP:76-2015), iv) High volume processed fly ash concrete pavements (IRC:SP:68-2005), v) Fibre reinforced concrete pavements (IRC:SP:46-2013), vi) Continuously reinforced concrete pavements- IRC:118-2015, vii) No joint sealant concrete pavements as per ACPA viii) Two lift concrete pavement/bonded concrete pavement (IRC:58-2015) ix) Sound reduction technologies x) Evaluation of Rigid pavement using falling weight deflectometer (IRC:117-2015) The paper thus describes new, cost effective, ecofriendly and practically need based advancements for making good quality concrete pavements and their evaluation for saving time and energy which are essential requirements for more infra-structure development with the creation of more jobs to the semi-skilled younger generation.

SHRP2 R21 Project Implementation: Two-Lift Concrete Paving on I-65, Nashville

Under Strategic Highway Research Program 2 (SHRP2) Project R21, detailed design and construction guidelines were developed for new composite pavement systems. These systems, consisting of either a hot-mix asphalt (HMA) or portland cement concrete (PCC) wearing course over a structural concrete layer (i.e., HMA/PCC or PCC/PCC), are promising technologies for providing sustainable roadways that can be constructed rapidly and rehabilitated (or renewed) with minimal disruption to the traveling public. New composite pavement systems have proven to provide long service life, excellent surface characteristics, exceptionally smooth ride quality, and high durability. As part of the SHRP2 Implementation Assistance Program, the Tennessee Department of Transportation (TDOT) integrated a two-lift (wet-on-wet) concrete composite pavement into a full-depth shoulder adjacent to a mainline reconstruction project on I-65 in Nashville. TDOT’s interest in the two-lift concrete pavement was driven by a recent specification change requiring a higher quality surface aggregate, and the I-65 project offered the opportunity to evaluate the viability and costcompetitiveness of the two-lift system. This paper describes the construction of the TDOT two-lift composite pavement, including critical aspects of the batching, transport, placement, and post-construction aspects of two-lift composite pavement construction.

Dispute in Heavy Duty Concrete Pavement Construction: Significance of Standards

This paper is an essay on the effect of standards and on problems and disputes that commonly develop in construction of heavy duty airfield pavements. It is intended to call attention to the need for improved standards for which research is needed to develop solutions to problems that develop in concrete airfield paving and tend to lead to owner-contractor disputes. Four construction scenarios that appear to suffer from insufficient specifications and consequently result in disputes are presented and discussed. Recommendations for potential improvements are made for each.

Long Term Performance of Sustainable Concrete Pavement Preservation Strategies in Canada

Rigid pavement preservation and rehabilitation strategies for high traffic volume roads are important sustainable methods of extending the life of our concrete roadways. In 1989, the Ministry of Transportation of Ontario (MTO) undertook the rehabilitation of an exposed concrete pavement exhibiting various distresses. The existing pavement, originally constructed in 1963, consisted of 230 mm mesh reinforced Portland Cement Concrete (PCC) pavement with dowelled joints at a spacing of 21.3 m. The preservation strategies used on the northbound lanes, which had experienced moderate deterioration, consisted of using sustainable concrete pavement restoration (CPR) techniques, material specifications and construction methods, which included full depth repair, partial depth repair, diamond grinding and joint sealant replacement. The rehabilitation strategy selected for southbound lanes was a 180 mm thick plain jointed unbonded PCC overlay to address the severe 'D' cracking and spalling at all the joints and cracks. This paper will identify the sustainable concrete pavement preservation strategies using the pavement sustainability rating system – GreenPave. It will also discuss the pavement preservation strategies and their long term performance evaluation in terms of roughness measurements, frictional resistance measured, and pavement condition ratings. Overall, the 22 year performance of these preserved and rehabilitated concrete pavements has been good with acceptable levels of ride quality, frictional resistance and distress propagation.

Stabilization of Soil Sub-grade Using GSB Material for Construction of Pavement

The construction of roads often necessitates soil stabilization in the sub-base and sub-grade regions when the soil exhibits poor strength due to softness, swelling, or low shear strength. While compaction can enhance many soils, it may not be sufficient for expansive soils, which necessitate the use of stabilizing agents, especially when dealing with weak or expansive soils. A crucial parameter in pavement design is the California Bearing Ratio (CBR), which measures soil strength. This study aimed to enhance CBR values by incorporating granular Sub-Base (GSB) material. Laboratory tests were conducted on various soil samples to determine their geotechnical properties, including Atterberg's limits, compaction characteristics, and CBR. The results indicated that increasing the percentage of GSB led to an increase in plasticity index and maximum dry density while decreasing optimum moisture content. Notably, CBR values significantly improved with higher GSB percentages. To achieve a CBR value exceeding 5, CL soils required 12-16% GSB, while CI soils needed 8-12%. This research provides valuable insights for optimizing GSB usage in pavement design, considering soil characteristics and traffic demands. Future research could explore the use of crushed demolition aggregates and fine marble powder, as well as evaluate permeability and consolidation characteristics for long-term performance and durability. . Key Words: Granular Sub-base (GSB), Atterberg’s Limit, Plasticity Index, Compaction, CBR, Expansive Soil.

Development and Demonstration of NDT for Evaluating the Curing Effectiveness of Concrete Pavement Construction

Early-age concrete surface moisture evaporation can be a factor during paving of concrete pavement resulting in plastic shrinkage cracking and spalling related delamination. The use of liquid membrane-forming curing compounds is one of the most prevalent methods to protect hydrating concrete surfaces. However, success in the application of curing compounds is not always assured under field conditions; lacking a tool to evaluate the curing effectiveness in terms of the uniformity and the rate of application are main issues. Previous research focused on the measurement of the surface dielectric constant (DC) of concrete as an indicator of the moisture retention capability of a given method of curing; however, the inherent limitations associated with the previous handheld technology prevents the method from being extensively utilized under field conditions. To employ better curing practices and the qualification of the application of different methods of curing, this research considers the use of ground penetrating radar (GPR) technology to measure DC at the surface of a concrete pavement. Analyses of the DC measurements indicated that the GPR system provided a very useful means to rapidly and extensively evaluate the curing effectiveness over a broad extent of a paved surface with great data repeatability; visual observations and statistical analyses validated that the system was able to suggest the uniformity of curing applications and differentiate the effectiveness of various curing applications due to varied rates of application. The research also reinforces the notion that the moisture retention capability of a given method of curing increases with the increase of the rate of application and improvement of curing uniformity.

PROPOSED SPECIFICATION FOR CONSTRUCTION OF AIRFIELD CONCRETE PAVEMENT

The Standards for Specifying Construction of Airports, FAA Advisory Circular: AC 150/5370- 10B incorporates Item P-501 – Portland Cement Concrete Pavement. Airfield concrete pavement project funded under the Federal Airport Improvement Program (AIP) are typically developed in accordance with the requirements contained in Item P-501 and sometimes in conjunction with specific project requirements and local practices related to material availability and regional concerns, and as approved by the FAA. Item P-501 provides guidance on the following: 1. Concrete materials (including composition and materials requirements) 2. Construction methods (including equipment, concrete placement, finishing, jointing, curing, and sealing) 3. Method of acceptance (including sampling and testing) 4. Contractor quality control 5. Basis for payment As part of a recent study, a proposed specification for construction of concrete airfield pavements has been developed for possible adoption by the FAA. The proposed specification places emphasis on the need to produce a durable end product, vis-à-vis, a durable concrete pavement. The product requirements that are specified are a combination of prescriptive requirements for certain materials as well as end product requirements for the as-delivered concrete and for the as-placed concrete. There is less emphasis on the means and methods to produce the end product. This should allow the contractor reasonable flexibility to use innovative construction methods and equipment that will result in cost savings to owner agencies without sacrificing the quality of the product. Specifically, the proposed specification will allow constructors to identify sources of variability in the airfield concrete pavement construction process and to minimize the variability; thus delivering an end product that is consistent and durable. The proposed specification intent is to: 1. Inspire creativity and maintain a standard for the evaluation of the construction 2. Incorporate a system of measurement consistent with acceptance criteria that will validate the design parameters 3. Encourage innovation and be "results-oriented" 4. Result in a product of the highest quality and consistent with the available local materials. This paper presents highlights of the proposed specification.

Unique Aspects of the Design and Construction of the Bristol Motor Speedway CRC Pavement

The reconstruction of the Bristol Motor Speedway (BMS) track surface presented some unique challenges to the placement of a continuously reinforced concrete (CRC) pavement. Due to the steep embankments of the radial sections, it was not feasible to use a traditional type of bond breaker to isolate the CRC from the subbase layer and so it was determined to bond the CRC to the base and eliminate the interlayer from the pavement section. Reflection cracking from the subbase was a concern and as a counter measure special crack control precautions were taken to insure the uniformity of the crack pattern using early aged crack control which required additional modifications to the sawing equipment to adopt it to the geometry of the track. The design of the steel was also configured to account for the bonded condition and the geometry of the track.

Framework for Design and Construction of Long-Life Concrete Pavements

In the past, concrete pavements were routinely designed and constructed to provide low-maintenance service life of 20 to 25 years. In fact, the majority of the U.S. interstate and the primary system were designed on the basis of the 20 to 25 year initial service life. Experience has shown that pavements in high volume traffic corridors need to be designed and constructed to provide longer service life because of the difficulties in performing effective repair and rehabilitation activities along these high volume highway corridors. In addition, the public is no longer tolerant of frequent extended lane closures to perform repair activities. It is becoming an established practice in the U.S. to require that concrete pavements provide low-maintenance service life of 40 plus years. PCC pavements can meet this specific requirement if proper considerations are incorporated in the design and good construction practices, including use of sound concrete making materials, are followed. This paper provides an overview of current U.S. practices and efforts at optimizing pavement design features and construction practices to minimize early age failures and provide long-term low-maintenance service in excess of 40 plus years. The paper also provides a framework for ensuring that the critical design and construction features that impact long-term service are recognized and accounted for. The design and construction features discussed include features that improve slab cracking and deflection responses, features that minimize maintenance operations, and construction features that assure long-life pavement.

Design and Construction of Seamless Pavement on Westlink M7, Sydney, Australia

Design and Construction of Seamless Pavement on Westlink M7, Sydney, Australia

IMPROVED TECHNIQUES FOR ASSESSING RIDE QUALITY ON CONCRETE PAVEMENTS

Under current procedures used in Australia for testing and interpretation of road profiles it is difficult to identify and isolate pavement sections responsible for unpleasant ride vibration. For the construction of new concrete pavements, in particular, where subsequent correction of profiles is very expensive, there is a need for improved procedures to give early feedback of the ultimate ride quality. To help identify and treat pavement problem areas, numerical models were developed to simulate ride vibration and pavement grinding. The ride and grind simulation models cover four generic vehicle classes – passenger cars, heavy commercial vehicles, offroad recreational and sports utility vehicles and motorcycles – and conventional pavement grinding equipment. A number of vibration response presentation formats were developed to help quantify ride vibration severity, intrinsic unevenness and grind treatment effectiveness. The models and key findings of the study are presented in this paper through contrasting examples of responses from the models to a selection of road profiles before and after virtual (theoretical) remedial grind treatment.

Fifteen Years Performance of a Concrete Pavement Rehabilitation Project in Canada

The Ministry of Transportation of Ontario (MTO) undertook the rehabilitation of an exposed concrete pavement exhibiting various distress manifestations in the summer of 1989. Highway 126 in Southwestern Ontario is a four-lane divided arterial with 22,000 AADT and 9.6% commercial traffic in year 2000. The existing pavement, originally constructed in 1963, consisted of 230 mm mesh reinforced Portland Cement Concrete (PCC) pavement with dowelled joints at a spacing of 21.3 m. The rehabilitation strategy selected for southbound lanes was a 180 mm thick plain jointed unbonded PCC overlay to address the severe 'D' cracking and spalling at all the joints and cracks. The rehabilitation of the northbound lanes, which had experienced moderate deterioration, consisted of using the latest concrete pavement rehabilitation (CPR) techniques, material specifications and construction methods, which included full depth repair, partial depth repair, diamond grinding and joint sealant replacement. This paper will discuss the evaluation of this rehabilitated pavement in terms of roughness measurements, frictional resistance measured, and pavement condition ratings. Overall, the fifteen-year performance of the rehabilitated concrete pavements has been good with acceptable levels of ride quality, frictional resistance and distress propagation.