Properties Of Pavement Research Articles

Calibration of Effective Structural Number and Tensile Strain Models Using Traffic Speed Deflectometer (TSD) Data for Enhanced Project-Level Assessment on Flexible and Composite Pavements

Pavement deterioration models provide the basis for predicting future changes in network conditions, estimating future funding needs, and determining the effectiveness and timing of maintenance and rehabilitation activities. Determining the accurate structural condition of pavements helps identify effective maintenance strategies which enhance the sustainability and service life of pavements. This study aimed to use the Traffic Speed Deflectometer (TSD) and Fast Falling Weight Deflectometer (FFWD) for project-level evaluation of pavements and use pavement properties to calibrate current models that help to predict the structural condition of pavements. Model parameters were calibrated to determine the effective structural number and tensile strains at the bottom of asphalt concrete for asphalt and composite pavements from TSD deflections. Tensile strains from the KENLAYER highlighted varied behaviors for composite pavements. A significant improvement in the calibration was observed for asphalt concrete pavements. While the TSD has higher daily operational costs than FWD, its per-mile cost is significantly lower, making it a viable choice for extensive coverage, even though the quantitative results might differ between the two devices.

Analysis of the influence of 2D and 3D void distribution characteristics of matrix skeleton on the mechanical properties of semi-flexible pavement: industrial CT scanning and 3D reconstruction

ABSTRACT This study aims to clarify the specific impact of the void distribution characteristics of the matrix skeleton on the mechanical properties of semi-flexible pavement (SFP) and form a targeted control method for the mechanical properties of SFP based on the gradation design of the matrix skeleton. Therefore, based on industrial CT and 3D reconstruction methods, this study comprehensively analyzed the matrix skeleton's two-dimensional and three-dimensional void distribution characteristics and conducted correlation analysis with the mechanical properties such as compression characteristics, tensile characteristics, dynamic modulus characteristics, and cracking characteristics of SFP. Research has found that the strength and rigidity of SFP are mainly positively correlated with the porosity and void's aperture of the matrix skeleton. The toughness of SFP is mainly positively correlated with the uniformity of void distribution and the three-dimensional void relative surface area index. The three-dimensional void relative surface area index is the most critical indicator affecting the mechanical properties of SFP, followed by the uniformity of void distribution, porosity, and the void's aperture.

Decay Characteristics of Mechanical Properties of Asphalt Mixtures under Sizeable Wet Temperature Cycle

Asphalt mixtures will inevitably be affected by rainwater and the effect of the wet temperature cycle during a pavement’s life span. Especially in coastal areas such as Guangdong and Hainan in China, asphalt pavement is particularly susceptible to the sizeable wet temperature cycle formed by the high temperature and sudden temperature drop of rainstorms in summer. For this study, we used a homemade sizeable wet temperature cycle environment simulation device to analyze the decay characteristics and the mechanical properties of asphalt pavements in this environment; modified bending and tensile strength and shear strength tests were used to study the decay patterns of shear strength, bending, and tensile strength, and the stiffness modulus of asphalt mixtures with different air voids and different pavement depths under the action of a sizeable wet temperature cycle. In addition, the Grey correlation method was used to analyze the significance of each influencing factor on the decay of mechanical properties, and mathematical fitting was used to establish the prediction equation of the mechanical properties of asphalt mixtures. The results show that with the increase in the number of sizeable wet temperature cycles, the asphalt mixture’s shear strength, flexural tensile strength, and flexural tensile modulus decrease, the degree of decay increases, and the rate of decay gradually slows down. In the case of the same number of sizeable wet temperature cycles, the degree of decay of the asphalt mixtures gradually decreases with increasing depth or decreasing void ratio. After 100 sizeable wet temperature cycles, the maximum values of the decay of shear strength, modulus of strength, and flexural tensile strength were 22.30%, 23.29%, and 32.01%. The importance of the influence of each factor on the decay of the mechanical properties is as follows: the number of sizeable wet temperature cycles > void rate > depth. The prediction equations of the established mechanical properties have a good prediction effect, and the correlation between predicted values and actual values can be up to 0.925. The prediction equations can effectively predict the mechanical properties of asphalt mixtures with different air voids and depths under the action of sizeable wet temperature cycles.

Effect of warm-mixing wax’s molecular weights on microstructure, rheological and mechanical properties of asphalt composites

The application of wax-based warm-mixing agents in pavement construction can effectively decrease the compaction temperatures of asphalt, leading to a reduction in greenhouse and harmful gas emissions. At present, many commercial waxes with different molecular weights are available on the market, but, wax with a high molecular weight can negatively impact the duration of the asphalt pavement. The effects of various warm-mixing agents on the structure and characteristics of asphalt composites were thoroughly investigated to quantify the molecular weights of wax. The obtained results suggested that the wax with an optimal molecular weight range of 1300 g/mol to 1500 g/mol had a significant viscosity-reducing effect and effectively increased resistance of asphalt composites against deformation and rutting at high temperatures; although the high-temperature features of asphalt composites were harmed by wax with low molecular weights (400–700 g/mol), it could further improve the low-temperature features of asphalt composites, particularly the resistance to low-temperature cracking. This work offers a useful method for balancing the high- and low-temperature properties of asphalt pavement by tuning waxes’ molecular weights.

Comparative Study between Recycled Fine and Coarse Aggregate Used in Roller Compacted Concrete Pavement

To decrease the impact on the environment of building waste, the recycled aggregate may be used in various sustainable engineering applications, such as roller compacted concrete pavement (RCCP). This research examined how using recycled aggregate as a partial replacement for natural aggregate as coarse or fine affected the mechanical properties of roller-compacted concrete pavement. The recycled aggregate was crushed and sieved to coarse and fine aggregate before being used in the roller-compacted concrete pavement. Compressive strength, splitting tensile strength, and flexural strength were all evaluated after the samples were prepared at 28 and 90 days of curing. According to the study's findings, the partial replacement of coarse or fine aggregate with recycled aggregate by (10, 15 and 20%) by volume resulted in decreasing the mechanical properties and increasing the absorption and porosity of RCCP due to the contaminated cement paste on the surface of RCA when compared to the reference mix made with natural aggregate. Because the recycled aggregate contains un-hydrated cement particles, the results have improved after 90 days.

Acoustic labelling of tires, road vehicles and road pavements: A vision for substantially improved procedures

The EU requires vehicle tires to be tested for noise emission and labelled. Some other countries also have similar procedures. Preparations for labelling of acoustical properties of road pavements is also ongoing in EU. Road vehicles and their tires must be tested and meet noise limits worldwide. However, all cases involve problems with measurement methods and conditions, which create uncertainties higher than desirable to make fair decisions on which product to select. For tires and road vehicles the major obstacle is the test track surface, which cannot be sufficiently well defined and reproducible. Also, far from all products (tires) are measured, so commonly only the noisiest products are correctly labelled. Although attempts are made to go indoors to do the measurements, they are still for the foreseeable future going to be made outdoors, with all the influence of weather and seasons that this causes. The author has worked most of his long career with such issues and in this paper, the author outlines his vision of how most of the problems (uncertainties) can be reduced to acceptable levels, mainly by making measurements indoors, with reproducible and representative conditions for both the labelling and the actual noise emission in traffic.

Innovative Use of Waste PET-Derived Additive to Enhance Application Potentials of Recycled Concrete Aggregates in Asphalt Rubber.

Polyethylene terephthalate (PET) drinking bottles, rubber tires, and concrete are the very common municipal solid wastes, which are usually disposed of at landfills and stockpiles and cause continuous damage to the environment. Some studies have indicated that waste PET can be chemically converted into an additive for improving the overall properties of asphalt pavement incorporating natural aggregates, especially the moisture-induced damage resistance. However, it is not clear whether this PET additive still works for asphalt rubber containing recycled concrete aggregates (RCA). To well reveal this issue, this study first adopted a similar way to chemically recycle waste PET into the additive for modifying crumb rubber modified asphalt (CRMA) binder and then mixed the binder with the 13 mm maximum aggregate stone matrix asphalt containing 100% coarse RCA for preparing the mixtures. After a series of physicochemical characterizations of the PET additive, the moisture resistance, rutting resistance, low-temperature cracking resistance, and fatigue resistance of the mixture were systematically evaluated. The results showed that the PET additive is capable of improving the resistance to moisture and high-temperature deformation of asphalt rubber and helps greatly reduce the moisture-induced damage to the interfacial bonding layer. To be more detailed, the residual Marshall stability (RMS) value of RCA-CRMAM/1PET after 72 h of immersion is higher than 85% by contrast to that of RCA-CRMAM (77.1%), while the tensile strength ratio (TSR) value of RCA-CRMAM/1PET shows more than 80% compared to that of 65.2%. In addition, only 1% PET additive can enhance the high-temperature resistance of asphalt rubber containing RCA to rut and allow it to maintain higher resistance to rut after moisture-induced damage. 1% PET additive can help improve the bearing capacity of RCA-CRMAM under a low-temperature environment and delay its fatigue life at small stresses. Generally, with the successful introduction of PET additives to asphalt rubber containing RCA, more durable and sustainable highway pavement can be produced and applied in practice to alleviate the negative impacts caused by waste PET, waste tire rubber, and waste concrete.

Mechanical behavior of asphalt pavement on steel-concrete composite beam bridge under temperature-load coupling

Over the past few decades, steel–concrete composite beam (SCCB) bridges have been gaining popularity all over the world. However, distresses such as rutting, delamination and cracking may occur on the corresponding bridge pavement structure soon after open traffic. To alleviate pavement distresses and clarify the applicability of different pavement structures and materials, in this study, a targeted research method for the mechanical properties of SCCB bridge deck pavement under temperature-load coupling was proposed. The research elements and procedures of the SCCB bridge deck pavement were structurally analyzed and synthesized. In addition, a temperature-load coupling model of SCCB bridge deck pavement was established. The permanent deformation under different cumulative axle load action times was calculated and fitted, and then compared with the actual detected data. Finally, the mechanical response of pavement structures commonly used for SCCB bridges was analyzed. The results show that the absolute error of rutting depth between the field test and fitting result was small, which proved the rationality of the proposed method. Besides, for SCCB bridges, “AC + SMA” and “double-layer SMA” have better road performance. The conclusion of this paper provides reliable support for the maintenance and distress causes analysis of SCCB bridge deck pavement.

Thermal Properties of Asphalt Pavements Modified with a Lightweight Silica-Based Composite

Pavements are exposed to different external factors such as traffic loading, levels of moisture, and ambient temperature fluctuations. External temperature change affects the pavement’s temperature profile and therefore its behavior. Previous research states that the pavement’s surface temperature cannot be addressed by adjusting its thermal properties because it primarily relies on the color of the surface. Furthermore, the temperature gradients in the pavement’s temperature profile can be associated with thermal cracking, which is an aspect that has not been fully investigated. The objective of this article is to analyze the temperature profile of a modified asphalt pavement and its effects on the thermal gradients in different seasons. Consequently, the thermal properties of a modified asphalt pavement with a novel silica-based composite, developed at Arizona State University (ASU), called “aMBx” were calculated. Three types of mixtures were considered in this study: Control (0% aMBx), 10% aMBx, and 30% aMBx contents by weight of asphalt binder in the mixture. Moreover, slabs of 7.5 cm and 15 cm in thickness were built to monitor the thermal behavior in the field using wireless thermocouples, where the temperature was monitored and recorded for one year. In addition, a pavement temperature model was implemented using validated software developed at ASU. The full pavement temperature profile was simulated for the three types of asphalt mixtures discussed in this study. The results showed that the pavement surface temperature can be managed by changing the thermal properties, which, in this case, was driven by the materials and thickness of the materials. The temperature gradient was lower for the aMBx-modified pavements. Therefore, it was concluded that aMBx-modified asphalt pavements may lead to lower thermal susceptibility.

The behavior of permeable paving properties using different materials in their compositions: a review of the literature

This systematic review addresses the behavior of the properties of permeable pavements with different materials in their compositions, with the objective of raising the state of the art of this area of study in a worldwide scenario. For this, the largest possible number of papers available was listed, according to the eligibility and quality criteria, detected in the Engineering Village, Scopus and Science Direct databases. After reading the titles and abstracts of all identified papers, 28 were chosen associated with the theme, of which 15 were included for the review. This result made it possible to demonstrate that the compensatory technique of permeable pavement is used in several parts of the world, presenting satisfactory results. Several studies presented in this work aimed to replace or even introduce other types of materials in the composition of permeable pavements, seeking to achieve better results in their properties, especially in mechanical and hydraulic.

Laboratory study on the properties of concrete pavement containing blast furnace slag and Gilsonite

This study evaluated the mechanical properties and abrasion resistance of the concrete pavement when cement was replaced by the blast furnace slag (BFS) and Gilsonite at levels of 20%, 25%, and 30%, as well as 5%, 7%, and 9%, respectively. For this purpose, a total of ten mixing designs were made and cured for 28 days. The results showed that the compressive strength of mixtures containing two additives decreased. In contrast, the BFS20-G7 mixture satisfied the proposed minimum compressive strength. However, the flexural strength and tensile splitting of the BFS20-G7 containing 20% BFS and 7% Gilsonite increased by about 4 and 7 percent. The Wide Wheel Abrasion Test results showed that the mixture containing 20% BFS-7% Gilsonite increased the abrasion resistance by about 5% and 17% in 100 and 300 revolutions, respectively. Conclusively, using BFS20-G7 in low-traffic areas such as parks and driveways can be suggested.

Effects of Transverse Cracks on the Backcalculated Layer Properties of Asphalt Pavements from Non-destructive Testing Data

Effects of Transverse Cracks on the Backcalculated Layer Properties of Asphalt Pavements from Non-destructive Testing Data

Investigating the Properties of Drainage Concrete Pavement through the Pore Creation Method: A Study

Background: Over the past decade, the pervious concrete pavement has become a popular innovation due to its highly porous spaces that allow for easy air and water flow from the surface to the underlying layers. However, the increased void content could potentially make the concrete weaker and less durable, which creates a need for alternative methods to maintain its strength while improving its drainage capabilities. Objective: This study aims to analyze the characteristics of drainage concrete pavement using a novel method for creating pore structures. Methods: To address the challenges of conventional concrete pavement, various pore patterns and diameters were examined, including a 2x2, 3x3, and 4x4 row arrangement with pore diameters of 2, 3, and 4 mm. The concrete mixture was formulated to comply with the standards established by the Department of Highways in Thailand. The study analyzed both the fresh concrete properties, such as slump test and setting time, and the hardened properties, such as compressive strength, flexural strength, and water absorption. The draining capability was evaluated through water permeability performance and the clogging effect was measured by very fine sand particles. Results: The test results showed that the slump value of concrete complied with the design specifications, and the initial setting time was recorded to be 230 minutes. The compressive strength and flexural strength tended to decrease while water absorption tended to increase as the pore pattern arrangement and pore diameter increased. However, the compressive strength of all mixtures exceeded 85% when compared to the control. Additionally, the water permeability coefficient ranged between 2.69-18.52 mm/s, and the permeability coefficient tended to decrease when the clogging effect occurred in the range of 18.18-37.27%. Conclusion: The findings of this study contributed to our understanding of the properties and behavior of concrete with pore creation. By refining our knowledge of the intricate correlation between porosity and compressive strength, it has become evident that reducing porosity is necessary to enhance the mechanical properties of concrete and ensure its long-term durability. Furthermore, sustainable infrastructure applications can improve the relationship between permeability and effective porosity through construction techniques.

Fibers in Asphalt Mixture: A State-of-The-Art Review

The use of fiber in asphalt mixture is gaining popularity as it can improve the mechanical properties of the asphalt pavement and enhance its durability and longevity. The main objective of this review is to discuss the recent research on the use of fiber in asphalt mixture and to provide an overview of its effects on the mechanical properties of asphalt. The article presents a review of the literature on the use of different types of fibers in asphalt mixture, including natural fibers, synthetic fibers, and glass fibers. The mechanical properties evaluated include stiffness, fatigue resistance, crack resistance, and rutting resistance. The review highlights the potential benefits of using fiber in asphalt mixture, including improved stiffness and crack resistance, reduced rutting, and increased fatigue resistance. However, the effectiveness of fiber in improving the mechanical properties of asphalt is influenced by various factors, such as fiber type, content, and distribution.

Reweighted L1 Minimization for Networkwide Weak Spot Detection from Traffic Speed Deflectometer Measurements

The traffic speed deflectometer (TSD) can collect network-level deflection data in a cost-effective and timely manner. However, an automated feature extraction method is needed to interpret such large amounts of data. Basis pursuit (BP) is one such technique: BP can sparsely decompose TSD measurements over a given basis or set of bases of the signal vector space that can represent a particular signal feature. For instance, the TSD surface deflection estimates can be reconstructed as a combination of wavelets, which represent continuously varying features like changes in pavement properties, plus pulses representing the response from structurally weak spots. Yet, the denoised measurements estimated by BP may either be riddled with several false positives (spikes that mismatch real weak spots) or be constructed out of true positive features with damped amplitude. This paper presents reweighed L1 minimization (RWL1), an enhancement to BP to both correct the dampening and discard false positives. This paper introduces RWL1 with examples from simulated data to show its advantage over vanilla BP denoising, plus a demonstration featuring real TSD measurements from a networkwide survey to demonstrate RWL1’s potential as an exploratory analysis tool to detect structurally weak locations within the pavement network worthy of further investigation at the project level.

Research on pavement performance of recycled asphalt mixture based on separation technology of asphalt and aggregate in RAP

Asphalt-aggregates separation of reclaimed asphalt pavement (RAP) with bio-oil as solvent is an economical, simple, and efficient method to recycle RAP materials. The byproducts of asphalt-aggregates separation of RAP are recycled aggregates and blends of bio-oil and old asphalt (BBOA). In this paper, to improve the recycling rate of BBOA and recycled aggregate after asphalt aggregate separation, Buton Rock Asphalt (BRA) is used as a high-temperature property modifier to compensate for the aging resistance and high-temperature of BBOA. The physical properties of rock asphalt modified bio-oil asphalt (RMBA) with different amounts of BBOA were studied by viscosity, frequency scanning, multiple stress creep, bending beam rheology, and aging tests. At the same time, recycled aggregates of different particle sizes and RMBA were used to prepare asphalt mixture with diverse mix design methods. The pavement properties of the recycled asphalt mixture were evaluated by rutting resistance, low-temperature bending beam, freeze–thaw splitting, and fatigue tests. The results show that RMBA realizes the complementary advantages of BRA as a high-temperature modifier and BBOA as a low-temperature performance modifier. The recommended dosage of RMBA is 20 %rock asphalt and 7 %BBOA. Under different preparation methods, the pavement performance of rock asphalt modified bio-oil asphalt mixture, asphalt mixture containing coarse recycled aggregate, and asphalt mixture containing oil sand meet the requirements of asphalt pavement design specifications, the preliminary realization of 100% recycling of RAP.

Effect of ozone aging on the rheological and chemical properties of crumb rubber-modified bitumen

Crumb rubber can not only solve the environmental pressure but also improve the properties of bituminous pavement. To study the characteristics and mechanism of ozone aging on CRMB, the effects of ozone aging on the rheological properties and chemical composition of crumb rubber-modified bitumen (CRMB) were explored. It was also compared with thermal oxygen. The results show that the macromolecules such as aromatic rings and polar functional group were formed after ozone aging, and the average molecular weight of CRMB increased. Ozone reacted rapidly with the CRMB surface at the beginning of the reaction and leaded to an increase in surface roughness. The risk of fatigue cracking increased. The effect of ozone aging (3 days, 60°C, 1000 ppb) on CRMB was similar to that of long-term aging. The effect of ozone on CRMB was mainly due to the ozone sensitivity of the crumb rubber modifier.

The Use of Steel Slags in Asphalt Pavements: A State-of-the-Art Review

Steel slag is a by-product obtained through the separation of molten steel from impurities in steel-making furnaces. It can be produced by different types of furnaces (blast, basic oxygen, electric arc, ladle furnaces). The reuse of metallurgical slags in road pavements can pursue aims of recycling and environmental sustainability. Based on the extensive literature, the paper presents a state-of-the-art review concerning the use of slags in asphalt pavements, discussing the main controversial literature findings. Slag manufacturing processes, chemical, morphological, and physical characteristics, affect its contribution to the asphalt mixture, when it partially or fully substitutes natural aggregates. Legislative state-of-the-art environmental issues, weathering, and leaching aspects are also discussed. The main mechanical and durability properties of pavements containing different types of slags are analyzed based on laboratory and field studies. Generally, the higher mechanical properties of steel slag suggest that its inclusion in asphalt mixtures can provide high-performance pavement layers (excellent strength and stiffness, superior rutting and fatigue resistance, low moisture susceptibility). However, several research gaps still exist (e.g., mix design and seasoning procedure, bitumen–aggregate affinity, low-temperature behavior, brittleness); they are discussed to direct possible future study efforts to clarify specific technical aspects, such as, for example, the effect of slag morphology and physical properties on the final mix properties and the development of specific mix design guidelines.

Analysis of the use of solid waste in road asphalt coatings: a literature review

The precariousness of Brazilian road pavements, added to the problem of solid waste disposal, highlights the relevance of studies aimed at incorporating these materials into asphalt coatings. This procedure can improve the mechanical properties of pavements, as well as bring savings. In this context, this bibliographic research aimed to analyze the use of solid waste ore, PET and sludge from the Water Treatment Plant (WTP) in asphalt coatings. After selecting two studies that aborted the use of each of the aforementioned residues, a comparative analysis was carried out on the methods employed and results obtained, considering the applicable standardization. Results showed that the incorporation of aggregated iron ore residue promotes good results for light and moderate traffic, in places with temperatures below 60°C. Although it decreases the Resilience Modulus, the incorporation of PET waste into mixtures is still environmentally and economically viable. The use of WTP sludge is quite promising, since the technical requirements are met, especially in the case of tensile strength. In general, the results showed several potentialities of the use of residues in asphalt coatings. Thus, it is important that professionals and regulatory bodies develop more studies to prove and promote this more sustainable practice in engineering.

Research on evaluation method of asphalt mixture workability based on minimum mixing energy consumption

The workability evaluation of hot mix asphalt mixtures is of particular importance for the uniformity analysis of asphalt mixtures and influence of later asphalt pavement properties. Currently, workability tests and evaluation systems for hot mix asphalt mixtures are not perfect. In this study, we have developed a testing device, proposed an evaluation index, and established an evaluation system for asphalt mixture workability. The compaction degree, asphalt distribution uniformity evaluation index (ADU), aggregate distribution uniformity evaluation index (HA), and coated uniformity of asphalt film evaluation index (CUAF) were measured to verify the workability evaluation index of asphalt mixture. Test results demonstrated that the newly developed asphalt mixture workability testing device and workability evaluation index accurately quantified the shift law of asphalt mixture workability during mixing process. The variation of the workability law was affected by asphalt type, mixture type, and mixing temperature. Compactness, ADU, HA and CUAF were closely correlated with workability evaluation indexes, and R2 values were 0.73, 0.77, 0.94 and 0.8, respectively. Validation results of the workability evaluation index of compactness, ADU, HA, and CUAF showed that the newly proposed workability evaluation index for asphalt mixture was feasible and effective.