Search

Insufficient bonding within pavement material causes widespread propagation of traffic-induced stresses, leading to accelerated damage accumulation and significant reduction in the service life of flexible pavements. This research aimed to examine the effects of using bonding enhancers, specifically Polyalkylene Glycol-based (PLG) and Alkylamines-based (ALM), on modified asphalt binders to improve the bonding characteristics. These additives were utilized at different concentration levels, i.e., 0.5 % and 1.0 %, based on the mass of asphalt binders, with the aim of enhancing the bonding performance between the materials within the asphalt mixture composite. The effectiveness of the modified asphalt binders was compared to the conventional ones through laboratory tests, which included shear-compression and pullout tests. These tests were conducted to assess the bonding performance of the modified asphalt binders by preparing different sets of sandwich samples using concrete cube substrates. A sodium carbonate solution was used as a medium to accelerate the effect of moisture damage on samples during the conditioning process. Additionally, the bonding performance of the asphalt binders was evaluated through a series of pullout and shear-compression tests under designated moisture and aging conditions. The dynamic shear rheological (DSR) test results of Rolling Thin Film Oven (RTFO) and Pressure Aging Vessel (PAV)-aged binders incorporating bonding enhancers showed superior resistance to rutting and fatigue failure. Significant improvements in stress and shear strength were observed under moisture and aging conditions, highlighting improvements in the bonding performance of the modified asphalt binders. The incorporation of additives has positively contributed to the pavement performance, despite only a modest increase in bonding performance, tensile strength, and shear stress resistance. [Display omitted] • Poor bonding accelerates damage accumulation and shortens pavements' service life. • A study was conducted to assess the bonding based on shear compression and pull-out tests. • A sodium carbonate solution was used to accelerate the moisture damage. • Bonding promoters were incorporated in asphalt mixtures to improve adhesion bonding. • Bonding promoters improve bonding and shear strength, hence better mixture performance. [ABSTRACT FROM AUTHOR]

Highlights • A new asphalt foaming protocol was introduced in this study. • Foamed binders were prepared using physical and chemical foaming agents. • The rheological properties and expansion ratio were characterized. • Ethanol lowers the viscosity of asphalt binders at low temperatures. • NaHCO 3 improves the expansion ratio and the resistance to rutting. Abstract The objective of this study is to characterize the foamed asphalt binders prepared using different combinations of physical and chemical foaming agents. The foamed asphalt binders were investigated using the Rotational Viscosity (RV), Dynamic Shear Rheometer (DSR) and expansion ratio tests. Asphalt binders were also evaluated after short-term and long-term aging conditions. During the asphalt binder's foaming process, the preheated binder was formerly foamed using a physical foaming agent (either water or ethanol), followed by the addition of sodium bicarbonate (NaHCO 3) to improve the bubbling and the stability of the foam. Theoretically, through this process, numerous bubbles are generated by the vaporized ethanol or water, and the gases are released by NaHCO 3 , which significantly increases the volume of foamed asphalt. All foamed asphalt binders were produced at the same temperature, 100 °C, to diminish the inconsistency of binder-aging conditions during the preheating process. Overall, the results indicated that ethanol has better characteristics in lowering the viscosity of asphalt binders at low temperatures and is expelled from the asphalt binder after continuous heating at temperatures higher than its boiling point (78 °C). Although the addition of NaHCO 3 has slightly increased the foamed binder viscosity that may affect its workability, it substantially lowers the volatile loss of foamed binders, as well as significantly improves the expansion ratio and the resistance to rutting. [ABSTRACT FROM AUTHOR]

• Effects of corrosion on the crack healing potential of asphalt mastic with steel fiber was assessed. • Samples being introduced to sodium chloride (NaCl) solution to accelerate the corrosion event. • Corrosion shows a negative impact toward the strength recovery, resistivity and temperature distribution. • Higher formation of rust can be noticed when a higher volume of steel fiber was used. • Yet, the corroded steel fiber within the asphalt mastic still able to induce heating and heal the crack. In the serviceability state of asphalt pavement, several pavement distresses are encountered; among them is the micro-cracks resulting from increasing traffic volume. Several maintenance and rehabilitation methods employed, such as patching and structural overlay are expensive and they consume a high amount of non-renewable resources. They also contribute significantly to the emission of greenhouse gases. It has been of a serious concern and interest among researchers to reduce the maintenance cost with a sustainable solution by introducing an induction healing technology via microwave heating system as a preventive maintenance approach. The microwave heating system requires a conductive particle in the asphalt pavement to accelerate the healing process. However, the steel fiber often used as the conductive particle is susceptible to corrosion under several environmental factors. Therefore, in this research, the effect of corrosion on the crack-healing potential was assessed using the water immersion method where the samples being introduced to sodium chloride (NaCl) solution to accelerate the corrosion event on copper-coated steel fiber. The formation of an oxide layer in the presence of moisture and oxygen on the surface of a copper-coated steel fiber shows a significant reverse impact on the ability of asphalt mortar to induce healing. A higher formation of rust can be detected when a higher volume of steel fiber was used. The study shows that the best performance of the copper-coated steel fiber is 3% (by volume of asphalt binder) based on the crack-healing potential, resistivity, and temperature distribution. [ABSTRACT FROM AUTHOR]

Highlights • Ethanol based foamed WMA mixtures were prepared and evaluated. • Ethanol-NaHCO 3 based foamed mix were prepared and the performance was evaluated. • Nano-hydrated lime improved the resistance to moisture damage. • Foamed WMA mixtures had comparable or better performance to control HMA mixture. • Combinations of ethanol with 1% NaHCO 3 was optimal for performance of mixtures. Abstract The foaming techniques implemented in Warm Mix Asphalt (WMA) have been highly recognized to aid in the production of eco-friendly asphalt mixtures. However, to a certain extent, the application of this technology is limited by its defects in moisture sensitivity and rutting resistance. Prior to this, the WMA mixtures were prepared using ethanol and ethanol-NaHCO 3 foamed binders and were tested to evaluate their moisture susceptibility, rutting potential, crack resistance and thermal cracking potential. The mixture samples were prepared based on the mixture design for a 9.5 mm nominal maximum aggregate size. The designed traffic level was less than 3 million Equivalent Single-Axle Loads (ESALs). Nano-hydrated lime was incorporated during the preparation of the sample as a filler material. The foamed WMA mixtures were prepared at three different temperatures: 80 °C, 100 °C and 120 °C; meanwhile, the control Hot Mix Asphalt (HMA) sample was prepared at 155 °C and 145 °C. For the purpose of incorporating the temperature losses during the foaming process, the foamed binders were produced at a temperature higher than the production temperatures by approximately 20 °C. Overall, the results show that 1% and 3% ethanol-foamed WMA mixtures are found to have a comparable or better performance than the control HMA mixture, especially for the samples prepared at 120 °C. The addition of nano-hydrated lime contributed to the increase on the adhesive and cohesive characteristic of mixtures; hence, improving the resistance to moisture damage. Regardless of the contents of the foaming agent and production temperatures, most of the foamed WMA mixtures prepared using a combination of foaming agents have comparable thermal cracking characteristics as the control HMA mixture. The resistance to rutting of foamed WMA mixtures increased with the increase in the production temperatures. The sample prepared at 120 °C is found to have much lower or comparable rut depths to the control HMA mixture. However, the combination of ethanol with 1% NaHCO 3 was optimal for these foamed WMA mixtures prepared at 80 °C to obtain a good long-term performance. [ABSTRACT FROM AUTHOR]

In this study, the effect of fly ash (FA) as an alternative filler mineral was evaluated regarding workability, structural performance, durability, and its sustainability when prepared using hot (HMA) and warm mix asphalt (WMA) technologies. The results revealed that workability of HMA and WMA samples containing FA are comparable to the mixes containing cement powder, yet the WMA mixes containing 4% Sasobit® prepared at 145 °C exhibited the highest workability, regardless of filler type. However, the compaction energy index (CEI) of WMA samples containing FA is more sensitive to the Sasobit® content variations at each mixing temperature. Besides, use of FA as an alternative filler mineral increased the resilient modulus up to 7.5% as compared to HMA and WMA containing cement powder. The tensile strength ratios of asphalt mixtures containing FA are not only satisfied the design criteria, but it is also higher than those of samples with cement filler. Use of WMA technology improves sustainability in the construction phase, while incorporation of FA filler decreases the greenhouse gas emissions during the raw material manufacturing stage. Therefore, synergistic effects of using the WMA technology and FA improve the sustainability of both construction and raw material processing within the cradle to gate phases. In conclusion, a higher workability and resilient modulus test result together with less environmental emission indicate that the WMA technology using Sasobit® and FA as an alternative filler are showing great potential for the production of eco-friendly asphalt pavement. [ABSTRACT FROM AUTHOR]

Applications of foamed binder have been spurred by the increased focus on sustainable construction approach and stringent environmental laws. This study was initiated to evaluate the performance of foamed asphalt binder produced using a combination of physical and chemical foaming agents, known as ethanol and sodium bicarbonate (NaHCO 3 ), respectively. This paper presents the properties of foamed asphalt binder assessed using Fourier transform infra-red (FTIR) spectroscopy, asphalt binder cracking device (ABCD), and activation energy analysis. The FTIR test was conducted to evaluate the possibility of any chemical reaction taken place, as well as to characterize the effects of oxidation on the chemical functional groups present in foamed asphalt binders. The ABCD test was carried out to evaluate the thermal cracking temperatures of prepared binders. The activation energy of each binder type was analyzed based on the viscosity test results and Arrhenius equation to estimate the energy required to overcome the intermolecular forces between the molecules in the asphalt binder to initiate flow. The FTIR results reveal that ethanol alone is unreactive with the binder, where most of the functional groups have shown comparable change ratios. This indicates that there are no chemical reactions that occurred in the foamed asphalt binders, either with the addition of ethanol or various combinations of ethanol and NaHCO 3 . The application of foaming agents definitely lowers the activation energy to overcome the intermolecular forces between the molecules in the asphalt binder to allow flow to occur. The foamed binders were found to have a comparable or better low temperature characteristic as compared to the control binder. A higher dosage of foaming agents proportionally increased the resistance to thermal cracking of asphalt binders. Overall, the use of foaming technique and newly proposed foaming agents has shown great potential to produce eco-friendly pavement material. [ABSTRACT FROM AUTHOR]

Asphalt foaming techniques have been used over the last couple of decades as an alternative to the traditional method of preparing asphalt mixtures. Various efforts have been initiated to assess the technology and enhance its efficiency during production. In this article, a comprehensive review of foaming warm mix asphalt (WMA) techniques, foaming theory and mechanisms, research and development as well as characterization procedures are presented. This paper also summarized numerous research and paving applications using foaming WMA technologies in Europe, the United States, Canada, China, Australia, New Zealand and some other countries. Findings from laboratory tests and field performance are also presented. Based on several field trials, the performance of foaming WMA is comparable to conventional HMA. The United States was found to be the most active country working on research-based and field trial evaluations on WMA besides two European countries: Germany and Norway. In addition to reducing energy consumption, reductions in fuel usage have significantly reduced the stack emissions of greenhouse gases, such as carbon dioxide, sulfur dioxide, and nitrous oxide. This review concludes with some recommendations in terms of diversifying the foaming agent and selection of test parameters in order to have a better precision and repeatability of test results. [ABSTRACT FROM AUTHOR]

Mortar creep takes place when the asphalt mortar continuously migrates downwards due to gravitational forces and can significantly disrupt air voids continuity in porous asphalt samples. This study was an extension to a previous work that ascertained the existence of the binder creep phenomenon as reflected from the continual permeability loss especially on samples conditioned at elevated temperatures. Nonetheless, in this paper, the terminology “mortar creep” was adopted instead of “binder creep”. This is because, in an asphalt mixture, the aggregates are glued together not by the binder in isolation, but by the mortar; which is comprised of asphalt binder, fine aggregates and filler. The variables investigated included aggregate gradation, binder type, bitumen content and conditioning temperature. The mixes were prepared using conventional bitumen (60/70 pen. grade) and modified asphalt binder (PG76) at three levels of binder content at 0.5% increment. Permeability loss was continuously monitored over an extended period up to 120 days using a simple falling head water permeameter. Over the test period, the samples were separately conditioned at 15 °C, 20 °C, 30 °C and 35 °C. The results showed that all factors significantly affect the occurrence of mortar creep in porous asphalt prepared in the laboratory, especially for the specimens conditioned at the highest temperature. Permeability loss was more significant on specimens’ prepared using conventional binder at a higher bitumen content. [ABSTRACT FROM AUTHOR]

This study evaluated the performance of e-waste modified asphalt binders. E-waste modifiers Acrylonitrile Butadiene Styrene (ABS), Acrylonitrile Butadiene Styrene-Polycarbonate (ABS-PC) and High Impact Polystyrene (HIPS) were used after 100% of the material passed through a #50 (300 μm) sieve. A conventional asphalt binder, PG58-28 binder, was used as a control. The e-wastes were blended with the control binder as untreated (UT) and chemically treated (T) modified binders. Chemically treated (T) modifiers were processed with cumene hydroperoxide before blending into PG58-28, to promote covalent molecular bonding between the e-waste plastic and asphalt. Results showed that untreated e-waste modified asphalt binders were stiffer and more elastic behavior than the control binder, but when these same e-waste plastics were first treated with cumene hydroperoxide, the increases were significantly higher. Use of chemically treated e-waste modifiers also significantly improves the resistance to rutting of asphalt binders, as shown by the work dissipated per loading based on the analysis conducted at 1.59 Hz. The improved results are attributed to the cumene hydroperoxide promoting direct covalent molecular bonding between e-waste plastic powders and the asphalt binder. These results suggest that when polymer modifiers are used in asphalt, radical reactions, at least at the interface with the modifier, should be promoted rather than prevented by added radical inhibitors. [ABSTRACT FROM AUTHOR]

One of the major concerns with WMA is degradation due to the presence of moisture during production. In the field, moisture in the aggregates may not be completely expelled due to a lower production temperature which increases the potential for moisture damage, including stripping. The objectives of this paper are: (1) to investigate the impact of hydrated lime on the moisture resistance of WMA mixtures prepared using saturated surface dried (SSD) moist aggregates; (2) to examine the effects of multiple freeze–thaw cycles on the moisture susceptibility of WMA mixtures. Testing samples were prepared in the laboratory with the materials from a local asphalt plant in Michigan according to the Superpave mix design. The control samples (HMA) were mixed and compacted at 165 °C and 155 °C, respectively. The WMA samples were prepared using different additives, which were Advera, Sasobit, Cecabase RT, and water as a foaming agent. For the moisture susceptibility evaluation, the mixtures were prepared using SSD aggregates and the WMA mixtures were both mixed and compacted at a similar temperature, 130 °C. Hydrated lime was added as an anti-stripping agent to determine whether or not it can improve the moisture susceptibility of the HMA and WMA prepared using SSD moist aggregate. The samples for the multiple freeze–thaw study were prepared according to a similar mix design at numerous temperatures (100 °C, 115 °C and 130 °C) and different percentages of WMA additives based on the specific ranges recommended by the manufacturer of each WMA technology. Each additive was added to the asphalt binder prior to mixing with aggregate based on the designated percentage. Based on the results, the presence of hydrated lime in the WMA has resulted in the TSR values passing the minimum requirement of 0.80. This indicates that by adding hydrated lime, the moisture susceptibility of the WMA can be improved. The WMA samples that were tested under multiple freeze–thaw cycles do not perform as well as the HMA samples. Different additives perform better at different quantities in the mixture, as well as at different temperatures. Lower mixing and compaction temperatures negatively affect the TSR after repeated freeze–thaw conditions. [ABSTRACT FROM AUTHOR]

This study aims to characterize the rate of change that takes place in the rheological properties of asphalt binders modified with numerous types and contents of nano-materials. The effects of nano-materials on the activation energy of modified asphalt binders under the viscous and visco-elastic behavior were also investigated. Through the research findings, the application of non-dimensional analyses using relative viscosity and relative G ∗ /sin δ (NSRP) are very meaningful to evaluate the rate of change in the rheological properties of asphalt binder per one unit percent of nano-material. It is also found that the non-dimensional viscosity index (∇ η ) and non-dimensional Superpave™ rutting factor gradient (∇NSRP) are influenced by the type and content of nano-material, and test temperature. The activation energy analysis has confirmed that the changes in amount of energy consumed are not only influenced by the type and content of nano-material, but also the physical phase of the modified asphalt binders. [ABSTRACT FROM AUTHOR]

The purpose of this project is to evaluate the possibility of using ethanol as a foaming agent for low emission asphalt technology via life cycle assessment (LCA) analysis. LCA analysis was conducted at two different stages. Firstly, the analysis was performed to estimate the energy consumption and CO 2 emission in the cradle to gate stages incorporating the effects of various foaming agent contents. In the second assessment, the analysis attempts to incorporate the required information based on the available published papers to get a clear idea about the energy consumption and GHG emission involved in all stages from the raw materials production to the end of life of asphalt pavement. The scope and boundaries of this analysis have been set based on several assumptions made prior to performing the analysis. LCA software, SimaPro 7.3, was used to estimate the cumulative energy demand and global warming potential (GWP) of Ethanol-foamed Warm Mix Asphalt (EWMA) and compare these to the results of Hot Mix Asphalt (HMA) and Water-foamed Warm Mix Asphalt (WWMA). Eco-Indicator 95 analysis was also conducted to establish the weighting factors for the various environmental effects of each asphalt mixture. Based on the results, it was found that the EWMA performed better in terms of energy demand, and lowered GHG emissions compared to HMA and WWMA. EWMA has high potential to reduce the detrimental impacts from the asphalt pavement industry based on Eco-Indicator 95 analysis, which has a lower impact in terms of GHG emissions, ozone layer depletion, acidification, eutrophication, summer smog, and winter smog, as well as energy resources. [ABSTRACT FROM AUTHOR]

[Display omitted] • This paper assesses the viability of using mineral fillers from industrial by-products. • Lime kiln dust and dolomite powder were studied and compared to cement powder. • Changes in asphalt binder phases occur as a result of asphalt-filler interactions. • The pH conditions dictate mastics adhesive tendencies due to electrostatic ionic exchange. • Thus, impacting pull-off strengths within asphalt-aggregate interfaces. The influence of filler particle mineralogy, pH and electrostatic charge on the adhesive tensile strength and morphological structure of asphalt mastic composites were assessed in this study. Three different fillers i.e., dolomite powder (DP), lime kiln dust (LKD), and ordinary Portland cement (OPC) together with a conventional PEN 60/70 binder were used for the asphalt mastic preparation. The mastics were mixed at dosages of (0.4, 0.8, and 1.2) filler to binder concentration (F/B) by volume as per the dust to binder specifications of Superpave mix designs. OPC mastic was utilised as the control mastic sample for all conducted tests, while the DP and LKD mastics were tested as sustainable alternatives to the OPC. The impact of filler inclusions in asphalt liquid phases was investigated via optical microscope assessments. Similarly, physicochemical tests of the elemental and mineralogical composition of each filler were accounted for using x-ray diffraction tests. The surface charge characteristics of each test filler was analysed relative to its mastic pH conditions through the application of zeta potential tests. Adhesive pull-off tensile strengths of the mastics on granite and limestone interfaces were also assessed for both dry and moisture conditions. The incorporation of fillers in asphalt binders highlighted the effect of filler reactivity and inert tendency on binders' morphological phase modification wherein the OPC and LKD were reactive with the asphaltene while the DP was less reactive and inert. Results obtained from both the x-ray diffraction and zeta potential tests also infer the calcium based OPC and LKD to exhibit better surface ionic attraction compatibility with the PEN 60/70 binder than the DP at high F/B. Meanwhile, the relationship between the filler surface charge and mastic pH condition was observed to be significant and reliant upon the mastics adhesive pull-off tensile characteristics. [ABSTRACT FROM AUTHOR]

Highlights: [•] This paper evaluates WMA using foamed admixture and free water system. [•] Higher mixing temperature has improved the rutting resistance and TSR. [•] ADVERA® WMA fatigue life is higher than the WMA foamed with water. [•] TSR of WMA foamed with water is higher compared to ADVERA® WMA. [•] Higher additive content and production temperature improve fatigue life. [ABSTRACT FROM AUTHOR]

Highlights: [•] Study quantifies effects of different NMAS and gradation break point on porous mixes. [•] Mixes were tested for permeability, abrasion loss, ITS and resilient modulus tests. [•] The results were statistically analyzed using analysis of variance. [•] A method was proposed to select suitable combinations of NMAS and break point. [•] Chart can be used as guide on selection of other porous asphalt gradations. [Copyright &y& Elsevier]

[Display omitted] • This paper evaluates lime kiln dust and dolomite powder as mineral fillers in asphalt mastic. • Differences in asphalt and filler properties causes changes in asphalt to particle interaction. • Thus, leads to differences in particle settlement, diffusion, energy dissipation and suspension rheology. • Incorporation of fillers with different properties and concentrations affects mastic behaviour. • Moreover, affect its performance predictability. The experimental investigation of the effects of filler-bitumen interaction on the stiffening and shearing characteristics of asphalt mastic is presented in this paper. The role of filler particles in terms of particle dispersion, particle sedimentation rate, particle dissipation energy, and their shearing response as a function of their viscosities under different concentrations was analysed. Structural and geometrical morphological tests of the filler particles were also carried out using the Scanning Electron Microscope (SEM) analysis. A neat bitumen of 60/70 penetration grade and two alternative mineral fillers, namely lime kiln dust (LKD) and dolomite powder (DP), were used to produce asphalt mastic mixture at a filler- bitumen ratio (F/B) of 0.4, 0.8, and 1.2 in accordance with the Superpave mix design dust to binder ratio specification. The two individual fillers particle size gradations, was assessed using a laser diffraction technique. The delta ring and ball, as well as the penetration index tests were conducted to determine the physical properties of the asphalt mastic. The shearing response of the asphalt mastic was also determined using a rotational viscometer (RV) device for various shear values at mastic mixing temperature. The results of the study inferred that the stiffening ability of mineral fillers was more dependent on the physical filler properties, such as particle surface area, voids between the interstices of particles, the concentration of particles, and the crowding distance of the particles in the asphalt mastic. It also revealed that the resistance of a neat bitumen to shearing occurs in a shear-thinning response behaviour, while that of an asphalt mastic occurs more as a shear thickening resistance response. The morphological analysis of both the fillers highlighted the differences in voids, fines, surface area, and particle shape structure of the two fillers. [ABSTRACT FROM AUTHOR]

• This paper evaluates usage of diluted methanol as a foaming agent (FA) in latex WMA. • Diluted methanol expand the latex modified binder's volume and lower its viscosity. • Hence, allows the production of latex modified asphalt mixture at lower temperature. • Application of methanol improve the service characteristics and mixture performance. • Incorporation of diluted methanol could promote environment sustainability. The modification of asphalt mixtures using latex has gained popularity in the asphalt industry as it improves the durability of road pavement. However, the elastomeric properties of latex stiffen the binder, resulting in more energy consumption during the asphalt mixture production. It would consequently cause a higher emission of greenhouse gases, which is undesirable for the human health and environment. This study aims to assess the applicability of diluted methanol as a foaming agent in asphalt mixture incorporating latex produced at a lower temperature. In this study, two designated amounts of diluted methanol (1% and 3% of the weight of asphalt binder) were successively injected with 6% latex into pre-heated asphalt binder at 135 °C in the preparation of foamed binders, while the control and latex modified asphalt mixtures were prepared at 160 °C. Tests of rotational viscosity, expansion rate, and torsional recovery were conducted to study the rheological properties of the mixtures. Service characteristics were evaluated through the indices of workability, compaction energy, and coatability. Moreover, mixture performance tests were carried out to identify the tolerance of the mixtures towards moisture damage, shear force, and permanent deformation. Through the rotational viscosity test, diluted methanol was found to reduce the viscosity of the asphalt binders, which is vital in the production processes at intermediate temperatures. The enhancement in viscosity using 3% diluted methanol had facilitated in higher workability, lower compaction energy, and better aggregate coating, which are the crucial criteria for a better mixing and compaction process. Whereby, a superior foaming quality was exhibited from the 3% diluted methanol application through the assessments of expansion ratio, half-life and foaming index. The moisture and shear resistances of the diluted methanol foamed asphalt mixtures are comparable to the control mixtures even though they were prepared at a lower temperature. Finally, the 3% diluted methanol foamed asphalt mixture promoted a better rutting resistance due to its ability to recover to the initial form which was demonstrated through its torsional recovery. [ABSTRACT FROM AUTHOR]

• Crumb rubber and natural rubber latex were used as bitumen's modifier. • Crumb rubber and latex improved the properties of modified bitumen. • Rheology of bitumen is dependent on modifier concentration. • Crumb rubber perform well in bond test while latex execute well in LPDS test. • Temperature sensitivity of modified bitumen were evaluated. The objective of this study is to investigate the rheological properties, bonding and resistancetoshear of the rubberized modified binders under different conditions. A base asphalt binder with penetration grade 60/70 was utilised in this study. The crumb rubber and natural rubber latex were added at different percentages for the modified bitumen production, and computed based on the mass of bitumen. Silane additives at the rate of 0.1% by mass of asphalt binder were used as a surfactant. A series of rheological properties and recovery test were conducted on all binders. While bond test and Layer-Parallel Direct Shear (LPDS) test were carried out in order to simulate the crack movement of pavement. The results show that the addition of crumb rubber and latex positively impacts the performance of the asphalt binder. The crumb rubber and natural rubber latex modified asphalt binder has comparatively identical elastic recovery outcomes, while it also helps in enhancing the stiffness in terms of softening and penetration value. However, natural rubber latex modified asphalt binder performed much better than crumb rubber modified asphalt binder in terms of torsional recovery. Whereas, rotational viscosity test has been useful in adopting the suitable temperature which is 160 °C in order to satisfy the needs of better workability and to ensure it is pumpable. Storage stability test proved that the modified asphalt binders are homogenous since the temperature differences are less than 5 °C. The dynamic shear rheometer (DSR) test proved that the modified asphalt binder has better resistance to rutting. Through DSR findings and activation energy, the modified asphalt binder were catogorize as less susceptible to temperature changes. Finally, the crumb rubber modified asphalt binder did well in terms of bonding strength, while the natural rubber latex modified asphalt binder performed well in terms of resistance to shear. Overall, both rubberized modified binders performed better than the control sample. [ABSTRACT FROM AUTHOR]

Highlights: [•] This paper evaluates the healing capacity of asphalt samples with induction energy. [•] Asphalt mastic and concrete beam samples were prepared by adding steel wool fibers. [•] The specimens were heated to different temperatures, including 60°C, 80°C and 100°C. [•] Fracture-healing cycles via three point bending test and induction healing were used. [•] The cracks can be effectively healed even after six fracture-healing cycles. [ABSTRACT FROM AUTHOR]

• Recycled Paper Mill Sludge as a filler in asphalt mixture is a feasible practice. • Recycled Paper Mill Sludge modified mixtures requires less asphalt binder content. • The optimum sludge content of 0.5% have been chosen as the most practical rate. • The elemental composition and mineralogical compound of sludge were assessed. • The incorporation of sludge comparatively improved the performance of mixture. As a developing nation that moves towards the sustainability, initiatives had been taken to address the solid waste disposal problem by incorporating them into asphalt pavement construction. This study integrates the recycled material named Recycled Paper Mill Sludge (RPMS) into the production of asphalt mixture as modifier through the partial substitution of mineral filler. The usage of solid waste material in pavement construction could substantially reduce the waste production and reduces the possibility of those waste materials ending up on landfills. This paper evaluates the microscopic analysis such as XRD, XRF and the mechanical properties of asphalt mixture with the incorporation of Recycled Paper Mill Sludge (RPMS). Mechanical properties that were evaluated were indirect tensile strength (ITS), moisture sensitivity, resilient modulus, Leutner shear and dynamic creep. RPMS was added to the asphalt mixture through dry process at the rate of 0.5% and 1%. Addition of RPMS at specific rate improved the mechanical properties such as resilient modulus, Leutner shear and dynamic creep of asphalt mixture. The lapped antenna like fibre of RPMS improved the resilient modulus of asphalt mixture by acting as a reinforcing material. Furthermore, RPMS contains calcite compounds that promote the adhesion bonding between asphalt binder and aggregates which significantly improved the performance in Leutner shear test and dynamic creep test. [ABSTRACT FROM AUTHOR]

Bio-asphalt is a binding agent that is made of bio-oil and petroleum asphalt, or bio-oil modified with incorporations of some other additives under certain conditions. This study was carried out to evaluate the properties of bio-asphalt binder-based in terms of the value of complex shear modulus (G ∗ ) and the phase angle (δ) tested by dynamic shear rheometer (DSR). Four bio-oil dosages of 5, 10, 15, and 20% based on the weight of asphalt (S100) were used to alter the SBS-modified binder. Whereby, the SBS content is approximately 1% of the weight of the virgin asphalt. The complex shear modulus and frequencies of virgin and short-term aged binders were tested. The master curves of rutting factor (G ∗ /sinδ) of different bio-asphalt were then generated to survey its rheological properties in a broad range of frequencies and temperatures. Based on the results, it was found that the addition of bio-oil extracted from sawdust has significantly increased the complex shear modulus of asphalt binder at the same frequency conditions after going through rolling thin film oven (RTFO), which is desirable for rutting prevention of asphalt mixtures. The rheological properties of bio-binders are more susceptible to the RTFO aging condition compared to the reference binder. The master curve of rutting factor of bio-binder indicated that the rutting factor of bio-asphalt increased with the increase of frequency before and after RTFO. Additionally, incorporations of bio-oil into the SBS modified asphalt, has greatly increased the rutting factor (G ∗ /sinδ) after RTFO, regardless of the loading frequency. However, the degree of enhancement was dominated by the percentage of bio-oil and aging condition. [ABSTRACT FROM AUTHOR]

• The various types of road pavement currently in use. • Review of the current research and results of using Ordinary Portland Cement (OPC) and various supplementary materials in rigid concrete pavements. • The use of waste materials in geopolymer as rigid concrete pavement. • Review of current research works of geopolymer concrete pavement with various geopolymer industrial by-products precursor. • The study of physical and mechanical properties of geopolymer concrete rigid pavement as well as a summary of standard testing methods and requirements. Rigid pavements are less expensive than flexible pavements and have a 20-year service life, making them more suitable for areas with weak subgrade soil and poor drainage. However, the use of rigid pavements comes at the expense of the environment. The production of cement has caused serious environmental problems, the most serious of which is the emission of carbon dioxide gas (CO 2) into the atmosphere, causing natural greenhouse effect and global warming. Sustainable materials aid in the reduction of CO 2 emissions as well as the use of natural raw materials in cement production. In the past few decades, significant progress has been made to develop alternative sustainable building materials (such as geopolymer cement/concrete) in order to control CO 2 emissions. Numerous studies have found that geopolymer is comparable to ordinary Portland cement (OPC) in terms of strength and chemical resistance. However, only a few studies have been done on the usage of geopolymer as a rigid pavement. From the review that has been done, it can be concluded that, in addition to high strength, the requirements for rigid pavement concrete material should include fast setting time, good workability and high durability. The review emphasized that geopolymers have been proven to have excellent strength, durability and processability which fulfil the requirement for rigid pavement application. Finally, this review also introduces future research opportunities regarding the potential of geopolymers as an alternative to OPC for rigid pavements. [ABSTRACT FROM AUTHOR]