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Rutting and moisture damage are the most common distress types in the pavement; therefore, agencies have adopted performance tests such as the Hamburg wheel tracking test (HWTT) to specify and screen the asphalt concrete rutting performance, following the AASHTO T324 standard. Many studies have shown that the AASHTO parameters can be used to characterize and rank the performance of asphalt mixes. Additionally, researchers proposed new analysis methods and performance parameters to provide a more systematic approach to analyzing the HWTT results. However, some of these performance parameters are determined subjectively by the operator, which may result in ambiguous values, preventing agencies from adopting them in the specification. On top of that, it is also unclear whether each analysis method or the performance parameters can universally distinguish the rutting performance when applied to various HWTT results. Thus, this study investigates the feasibility of different HWTT analysis methods among the performance parameters. 61 HWTT results from various material combinations were analyzed using three different data analysis approaches and calculating the performance parameters. The result showed that the current analysis methods and parameters have certain limitations in analyzing HWTT results. Therefore, a performance parameter, namely the Hamburg performance index (HPI), was introduced, incorporating the number of passes, maximum rut depth, and rut path history into one parameter. It was found that the HPI can resolve the limitation encountered by other analysis approaches and significantly improve the accuracy of distinguishing a mix's rutting and moisture resistance. [Display omitted] • The original Hamburg data analysis method was shown to create ambiguous results. • HWTT mathematical function curve-fitting results lead to a performance prediction error. • A new HWTT result analysis method was proposed. • The proposed parameter (HPI) can evaluate and distinguish HWTT results accurately. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electric arc furnace slag can improve the performance of rutting and abrasion resistance in slurry surfacing. • Electric arc furnace slag can reduce the carbon footprint in the slurry surfacing mixture. • Aggregate packing degree and asphalt-aggregate bonding value plays important role in the slurry surfacing mixture design. • Electric arc furnace slag can become a potential source for aggregate replacement in slurry surfacing. Incorporating Electric Arc Furnace Slag (EAFS) into construction materials such as hot-mix asphalt and Portland cement concrete has shown increasing wear and polishing resistance while reducing solid waste and mitigating the carbon footprint of construction engineering. Pavement surface treatment is one of the most used pavement preservation approaches. The slurry surfacing (SS) technique provides the most hot-mix asphalt-like surface texture among the surface treatment techniques. This study aimed to investigate the feasibility of using EAFS for SS by incorporating various amounts of EAFS and then analyzing the treatment's performance and the resulting carbon footprint reduction. Performance tests of SS, including the wet track abrasion test and loaded wheel test, were performed to evaluate SS's abrasion and deformation resistance. Aggregate packing degree and bonding strength based on the surface charge were also considered to understand the mechanism affecting the performance. The corresponding reduction in carbon footprint is then analyzed using the tiered hybrid life cycle assessment method to understand further the benefits of using EAFS in SS. The results revealed that mixtures incorporating EAFS could be carefully designed to perform better by increasing the packing degree and bonding strength. Also, adding EAFS into SS increased abrasion resistance by up to 18.2%, rutting resistance by up to 72.8%, and reduced the carbon footprint by up to 39.6%. [ABSTRACT FROM AUTHOR]

• Lignin extracted using H 2 SO 4 contains more phenolic compounds than that extracted using HCl. • Lignin successfully deagglomerating large-molecular size fraction in aged asphalt. • Lignin extracted using H 2 SO 4 has a better deagglomeration ability than that of HCl. • Using lignin from black liquor in recycled asphalt can potentially store and reduce carbon footprint. This study assessed the potential of lignin, derived from black liquor, for deagglomerating asphaltene fractions. Chemical and rheological tests were employed to evaluate the efficacy of the lignin additives. Gas chromatography-mass spectrometry (GC–MS) analyzed the chemical components of lignin (L1) isolated with sulfuric acid and lignin (L2) isolated with hydrochloric acid. Gel permeation chromatography (GPC) examined changes in molecular size distribution and deagglomeration effectiveness of the lignin additives. Fourier transform infrared spectroscopy (FTIR) assessed the chemical functional groups of asphalt, while the rheological performance of asphalt was evaluated through the crossover modulus (|G* c |) and frequency (ω c) analysis. L1, possessing high phenolic content and low pH, demonstrated deagglomeration effectiveness, achieving a 6% reduction in weight-average molecular weight, 3% in polydispersity index (PDI), and 16% in asphaltene fraction. Both L1 and L2 decreased the combination aging index of aged asphalt by 28% and 7%, respectively. Moreover, L1 and L2 enhanced the |G* c | of virgin and aged asphalt, consistent with the reduction in the PDI value. These findings suggest that lignin additives possess the potential to deagglomerate asphaltene fractions. The study highlights the potential of repurposing harmful substances from black liquor, traditionally incinerated to reclaim certain chemicals in pulp mills, for use in the pavement industry, promoting sustainability and resource conservation. [ABSTRACT FROM AUTHOR]

Highlights • Work of adhesion of may drop up to 50% when aggregate moisture content of 10%. • Bond energy of WMA mixes diminish less with increasing aggregate moisture contents. • PM binder bond energy showed about 6.7 times greater than that of AC20 binders. • Quadrant plot can effectively rank the asphalt-aggregate adhesion properties. Abstract Warm-mix asphalt (WMA) is one technology that has been found to have potential in minimizing the environmental harm caused by road construction activities. Its low mixing and compacting temperatures have opened great opportunities for more sustainable development. However, because WMA is mixed at low temperatures, the drying process of the aggregate may fail to dry the WMA completely. The binder-aggregate adhesion property can be damaged by moisture remaining from incomplete drying. The present study investigated the effects of aggregate moisture on the binder-aggregate interfacial characteristics of WMA by evaluating its surface free energy and adhesive bond strength. The results showed that for the Pen 60-70 binder type, the aggregate AG in general showed the higher bond energy and aggregate SD showed the lowest bond energy among three aggregate types. Also, the bond energy diminishes with increasing aggregate moisture contents but the percent drops in bond energy is less when WMA additives was included. For the PM binder, SL aggregate group showed the highest bond energy and SD aggregate group showed the lowest bond energy. For the work of adhesion, the results showed that with aggregate with 10% moisture contents has destructive effects on the work of adhesion which may decrease to 50% compare to dry aggregate condition. Finally, the four quadrant diagrams can be used to combine two distinct property of the bond energy and the work of adhesion as the hybrid performance indicator to rank the effect of moist aggregate to the adhesion properties at binder-aggregate interface. [ABSTRACT FROM AUTHOR]

• Lignin additive extracted using H 2 SO 4 (L-S) had high phenolic content and pH value. • Asphalt with L-S additive had the lowest reduction of crossover modulus due to aging. • Incorporating L-S into asphalt reduces the increase of asphaltene fraction due to aging. • FTIR test is more sensitive in measuring the lignin antioxidant performance than DSR and GPC. The main objective of this research is to investigate the effectiveness of lignin bio-additives derived from black liquor paper pulp as asphalt antioxidants. Two lignin bio-additives, H-L and S-L, were developed by acidifying black liquor with hydrochloric and sulfuric acid. The laboratory aging procedures used in this study included the Rolling Thin Film Oven and the Ultraviolet Chamber methods. The crossover modulus (|G* c |) and linear amplitude sweep (LAS) were measured using a Dynamic Shear Rheometer (DSR). Gel Permeation Chromatography (GPC) was also used to characterize the molecular size distribution of the asphalt binder. The combination of carbonyl and sulfoxide aging indices was measured using Fourier Transform Infrared (FTIR) spectroscopy. The S-L modified binder (S-LMB) demonstrated superior aging resistance compared to both the control binder (CB) and the H-L modified binder (H-LMB) by exhibiting the lowest reduction in |G* c |. Furthermore, the LAS test results showed that S-LMB provided the best resistance to aging due to the lowest decrease in fatigue life with age conditioning, followed by CB and H-LMB, with rates of 11%, 13%, and 16%, respectively. The GPC results also confirmed the efficacy of the S-L bio-additive as an antioxidant, exhibiting the lowest increment in asphaltene proportion attributed to age conditioning. The FTIR measurements successfully captured the antioxidant capability of both H-L and S-L bio-additives, with S-L performing better than H-L. Overall, the results suggest that S-L demonstrates superior antioxidant performance compared to H-L. [ABSTRACT FROM AUTHOR]

Currently, road and airport pavement construction uses approximately 90% asphalt, most of which is mainly derived from fossil fuels. However, with the improvement in oil refinery technology, the quality of asphalt binders is degrading gradually. Moreover, from the environment standpoint, fossil fuels are the main source of greenhouse gases, which lead to global warming. Consequently, there is an urgent need to develop a more sustainable binding material from renewable or other alternative resources to replace or modify the existing petroleum-based asphalt binder for the highway industry. The main objective of this study was to investigate the potential use of a bio-oil byproduct as a partial replacement for a bitumen-based binder. The properties of various blending combinations of a biobinder and asphalt binder were compared with those of an unmodified asphalt binder through several physical and rheological tests. The specific gravity of the biobinder was found to be higher than that of the petroleum-based binder. In general, biobinder blends have a higher viscosity than that of the unmodified binder at temperatures higher than 60 °C. Binders containing the biobinder at 25% and 50% have lower temperature susceptibility than that of the unmodified binder. Adding the biobinder at up to 25% does not significantly change the complex shear modulus of unaged binders, whereas rolling thin-film oven-aged biobinder blends show a higher complex modulus and greater viscosity than those of the unmodified binder. Moreover, the biobinder blends show higher G ∗ /sin δ, lower nonrecoverable compliance and greater recovery ability than those of conventional AC-20. [ABSTRACT FROM AUTHOR]

Frequent mill and overlay activities result in the production of a considerable amount of reclaimed asphalt pavement (RAP) materials. Many pavements that incorporated RAP exhibit a shorter service life than do those without RAP. One of the possible reasons is that certain RAP materials have already undergone multiple recycling processes during the past decade. This results in severe aging of the reclaimed asphalt binder (RAB). In this study, three severely aged RABs, two RAP blending scenarios, two virgin binders, and two commercial rejuvenators were used to investigate the feasibility of using severely aged binders for constructing pavements. The chemical and rheological properties of the rejuvenated severely aged binders were evaluated using high-performance gel permeation chromatography and a dynamic shear rheometer. The molecular size distributions of rejuvenated RABs revealed that the rejuvenators used in this study could rebalance the proportions of large, medium, and small molecular components among the rejuvenated RABs. However, the polydispersity values still enabled clearly distinguishing between virgin binders and rejuvenated RABs. Two performance parameters were used to evaluate the potential of age-induced damage as well as permanent rutting in the binders. A Glover–Rowe damage zone was evaluated, and it revealed promising results to distinguish among severely aged binders, virgin binders, and rejuvenated binders. Oscillation and multiple stress creep and recovery tests were performed to obtain rutting potential parameter G ∗ /sin( δ ) and J nr , respectively. The results indicated that all rejuvenated aged binders exhibited higher G ∗ /sin( δ ) values and lower J nr values compared with the control virgin binders. [ABSTRACT FROM AUTHOR]

[Display omitted] • The layer coefficients of CACSM from field test locations ranged from 0.22 to 0.24. By contrast, for granular and cement-treated bases, these values were between 0.07 and 0.14 and between 0.17 and 0.20. • The mechanical property test verified the self-healing ability of CACSM; coal ash appeared to considerably influence the secondary curing of the specimens. • The use of 100% CACSM as a pavement base is a viable solution that can contribute to the development of transportation infrastructure with enhanced concrete durability and reduced carbon footprint emissions. Coal fly ash (CFA) and coal bottom ash (CBA) are coal combustion's primary solid waste products. This solid waste management is a substantial challenge for power plants and local authorities. In order to apply coal ash as a pavement base material, the relationship of the mixture's mechanical properties with structural design parameters for pavement design and analysis must be explored. No study has investigated the mechanical behavior of the 100% coal ash cement stabilized material (CACSM) as a pavement base layer. Therefore, this study aimed to investigate the structural layer coefficient of CACSM used in the American Association of State Highway and Transportation Officials (AASHTO) 1993 pavement design guide. The study consisted of laboratory material characterization and field evaluation. The mechanical property test revealed that CACSM has a self-healing ability; coal ash appeared to influence the secondary curing of the specimens significantly. Strength towards the ends of stage I and stage II showed the influence of high pozzolanic on the CACSM, which resulted in improved long-term performance. The layer coefficients of the locations in the field test ranged from 0.22 to 0.24. By contrast, for the granular base and cement-treated base, these values were 0.07 to 0.14 and 0.17–0.20, respectively. The study findings show that CACSM as a pavement base is a viable solution that can help develop transportation infrastructure with enhanced concrete durability and lower carbon footprint emissions. [ABSTRACT FROM AUTHOR]

3D-printed concrete (3DPC) is a layered anisotropic material whose properties are significantly impacted by the production parameters. To design and analyze large-scale printed structures, it is vital to understand the spatial variation of material properties throughout full-scale printed components. Presented study addresses this need by presenting a comprehensive experimental investigation that explores the variation of physical, mechanical, and thermophysical properties across a full-scale 3DPC wall with an approximate height of 2.36 m. The cores extracted from the wall were categorized in terms of the extraction location along the wall height (upper (U) and lower (L)) and the alignment of the specimen's longitudinal axis with respect to the printing space (printing (P), translation (T), and deposition (D) direction). Additionally, direct shear and four-point bending tests were carried out on printed beams. Control samples, mold-cast from the same concrete mix, were used for comparison. Obtained results indicated a pronounced anisotropy and property variation along the 3DPC wall height. These were linked not only to the frequency and orientation but also to the porosity of the interfaces which was significantly influenced by the self-weight compaction of the layers and the progressively increasing concrete viscosity caused by pump system heating over time. CT investigations, rate of water absorption, and water penetration tests revealed sparse and less connected interstrip and interlayer porosity in the L samples. Depending on the sample orientation and loading direction, compressive strength, elastic modulus and splitting tensile strength increased by up to 108 %, 53 %, and 100 %, respectively, in the L samples when compared to the U samples. The same trend was observed in the Poisson's ratio, albeit to a lesser extent. The triaxial thermal conductivities of the L samples calculated from the transient plane source measurements were up to 26 % higher than those for the U samples. Given the limited number of studies on real-scale applications, the presented research can serve as a benchmark, offering valuable insights to explore and validate the 3DPC behavior on a large scale. • Strong spatial variability of 3DPC properties across a full-scale printed wall. • Porosity depends on printing-space directions and wall height. • Pore size, content and connectivity are critical determinants of performance. • Stronger and stiffer behavior at lower levels due to better compaction. • Enhanced understanding of 3DPC behavior for full-scale construction scenarios. [ABSTRACT FROM AUTHOR]