Binder Level Research Articles

Earthen construction: Demonstration of feasibility at 1/2 scale of poured clay concrete construction

Poured earth construction is a very promising alternative to cement-based construction, however it requires a large increase of productivity. Poured earth concrete can meet this issue, but is currently stabilized with cement leading to a high environmental impact. One possible solution is the use of alginate, a biopolymer, to provide a transient liquid–solid transition before the wall is effectively hardened by the long process of drying. Using design experiment, the impact of four parameters (water to binder ratio, dispersant ratio, alginate ratio and level of acidifier) has been investigated on the consistency and the mechanical properties. In this study the feasibility of the use of poured earth concrete stabilized with biopolymer is demonstrated through low wall manufacturing.

VECD analysis to investigate the performance of long-term aged bio-asphalt mixtures compared to conventional asphalt mixtures

The road industry is seeking solutions to reduce its dependency on petroleum-based products and its carbon footprint. This is leading to increasing interest in the so-called bio-binders, i.e. binders in which bitumen is partially replaced with bio-oils from renewable sources. Fatigue cracking is a major distress for flexible pavements and therefore the fatigue behaviour of innovative road materials (such as bio-asphalt mixtures) must be characterised in a reliable way. Within this framework, this study aims at comparing the fatigue behaviour of a bio-asphalt mixture and the corresponding conventional asphalt mixture. The two mixtures were laboratory-mixed and laboratory-compacted, and the only difference between them was the binder (a bio-binder containing 10% of wood-based bio-oil vs. a conventional bitumen having physical and rheological properties similar to the bio-binder). The mixtures were short- and long-term aged in the laboratory and subjected to complex modulus tests and cyclic fatigue tests. The results, analysed according to the viscoelastic continuum damage (VECD) theory, showed that, after short-term aging, the bio-asphalt mixture may be slightly stiffer and thus more prone to cracking than the control mixture due to a possible over-aging caused by the effects of high temperatures. However, the long-term aging susceptibility of the bio-asphalt mix was found to be less severe as compared to the control mix, leading to fatigue performance benefits in the long term and corroborating the results of previous investigations at the binder level. Overall, these findings further encourage the use of bio-binders as an alternative to traditional asphalt binders.

Opacity and Washability Properties of Emulsion Paint with Natural Rubber Latex/Polyvinyl Acetate Blend Binder

Polyvinyl acetate (PVAc) has long been known as a binder material to improve the washability, opacity (hiding power), and viscosity of commercial emulsion paints. This study aims to study the properties of opacity (hiding power), washability resistance, and viscosity of emulsion paint added with a binder from a mixture of natural rubber latex (NRL) and PVAc. Emulsion paint samples were made with a binder content of 4, 6, and 8% w/w. The binder was made from a mixture of NRL and PVAc with various NRL levels of 0%, 15%, 25%, 35%, 50%, and 100% w/w. Testing of paint samples includes washability using a digital BGD 526 Wet Abrasion Scrub Tester and viscosity testing using a HAAKE 6R digital viscometer. At the same time, the opacity test uses the Indonesian Standard (SNI 3564:2009). The results showed that the opacity met the standard emulsion paint for all binder levels, except for the composition of NRL 100% w/w at all binder levels. The higher the NRL content in the binder causes the washability resistance and paint viscosity to decrease and become unstable. The best washability resistance and viscosity properties were obtained at NRL in a binder of 15% w/w and a binder content of 8% w/w, with washability resistance properties of 50 times and a viscosity of 3300 cp.

Development of ternary binder mixing formulation for asphalt pavement recycling

ABSTRACT Recycling agents (as softening agents or, rejuvenators) are being widely used in the asphalt recycling process. At the binder level, recycling therefore involves three constituents, namely, virgin binder, aged binder (arising out of reclaimed asphalt pavement materials) and the recycling agent – making it a ternary binder blend. Limited literature is available on the ‘mixing formula’ for ternary binder blend that can be used to predict the resultant physical property of the blend, when the proportion and physical property of each of these three binders are given. The objective of the present research is to explore a suitable ternary mixing formula (relevant to hot asphalt recycling process) based on empirical observations in the laboratory. In this work, four different types of recycling agents (two softening agents and two rejuvenators) are used, and the complex viscosity is taken as the physical property. Temperature and frequency are also included as variables as an effort to improve the robustness of the suggested equation. Subsequently, a generalised equation is developed for the prediction of complex viscosity at any given temperature and frequency and the same is validated for the ternary binder mix dealt in the present study.

Healing kinetics of asphalt binder based on a new testing approach

Self-healing capability is one of the most important characteristics of asphalt binder, which has a significant influence on field performance of asphalt pavements. Although the internal stress has been proven to be the driving force of healing, limited studies have been conducted for this part. As a result, this study aims at proposing a new approach to measure the internal stress and quantify the relationship between healing capability and damage levels of asphalt binder from its causal relationship based on healing kinetics. Specifically, a new approach called creep and zero-strain-rate recovery (CZSR) test to measure the internal stress is proposed. The accuracy of this new approach is verified in both undamaged and damaged asphalt binder. Then, the application of this new approach is expanded from creep-recovery condition to multiple-cyclic-loading-recovery condition. This action not only expands the application fields of this proposed new approach, but also provides a bridge to evaluate the relationship between healing capability and damage levels from its causal relationship. After that, the healing-kinetics method is used to characterize the healing capability of asphalt binder under different damage levels on the basis of energy-based mechanistic (EBM) approach. Moreover, the healing capability and damage level of asphalt binder are expressed as healing activation energy and crack length, respectively. Final results indicate that the healing activation energy increases with the growth of crack length, and there is a negative relationship between healing capability and damage levels of asphalt binder.

Influence of nano-silica on the microstructural and mechanical properties of high-performance concrete of containing EAF aggregate and processed quarry dust

The present study investigates nano-silica (NS) in ternary binder composite and the influence of the same on Electrical Arc Furnace (EAF) slag coarse aggregate-based various high-performance concrete (HPC) mixes. Processed Quarry Dust (PQD) was used as fine aggregate throughout the investigation to limit the consumption of natural river sand and make HPC more sustainable. Control HPC was designed using the Ordinary Portland Cement (OPC)- Ground Granulated Blast Furnace Slag (GGBS) binary binder and various replacement levels of natural crushed granite rock aggregate by EAF coarse aggregate. Additionally, the binary binder composite was added with colloidal nano-silica to achieve high strength HPC. A microstructure study was carried out on paste samples of OPC, OPC with GGBS, and OPC, GGBS with the inclusion of nano-silica. FESEM, EDX, XRD, FTIR, and TGA results showed that the addition of nano-silica has significantly enriched the microstructure characteristics of the binder system. The slump flow of HPC mixes decreased drastically with the inclusion of nano-silica and EAF aggregate. Mechanical properties viz., compressive strength, split tensile strength, flexural strength, and modulus of elasticity of HPC mixes containing EAF and nano-silica have exhibited superior results due to the synergetic effect of nano-silica as well as the more robust physical characteristics of EAF aggregate compared to natural crushed granite rock aggregate. The UPV values and water absorption tests have shown that nano-silica positively affects the binder composite system.

Development of a Balanced Mix Design Method in Oregon to Improve Long-Term Pavement Performance

Most state Departments of Transportation (DOTs) and asphalt contractors do not think that commonly used asphalt mixture properties, such as voids in mineral aggregate (VMA), voids filled with asphalt (VFA), and dust-to-binder ratio, reflect the long-term performance of asphalt mixtures. In addition, there are several new additives, polymers, rubbers, and high-quality binder types incorporated into asphalt mixtures today. Volumetric mixture design methods are not capable of capturing the benefits of using all these new technologies on asphalt mixture performance. Furthermore, the interaction of virgin binders with reclaimed asphalt pavement (RAP) mixtures with high binder replacement contents and the level of RAP binder blending into the asphalt mixture are still not well understood. Because of all these complications related to the more complex structure of asphalt mixtures, simple volumetric evaluations to determine the optimum binder content may not result in reliable asphalt mixture designs. Two volumetrically identical mixtures may provide completely different rutting and cracking performance according to laboratory tests. For all these reasons, in this study performance tests for rutting and cracking are incorporated into current asphalt mixture design methods to make it possible to validate or revise the optimum binder content determined by the volumetric mix design method (the only method currently used for asphalt mix design).

High, intermediate and low temperature performance appraisal of elastomeric and plastomeric asphalt binders and mixes

This paper is oriented to appraise high, intermediate, and low temperature related performance of elastomeric and plastomeric binders and mixtures in order to evaluate their characteristics at various levels of environmental and loading conditions. Artificial oxidative hardening of asphalt binders and mixes was performed in the laboratory using short- and long-term aging protocols.At the binder level, the elastomers (styrene-butadiene-styrene (SBS) and rubber) and plastomer (ethylene-vinyl acetate (EVA)) materials improved high and intermediate temperature performance indices (G*/sin(δ) and G*.sin(δ), respectively). Interestingly, the aged SBS/bitumen blend had improved low-temperature cracking resistance compared to unaged counterpart. With the progress of oxidative hardening, the plastomer based binder did not show obvious change in the low-temperature cracking susceptibility compared to elastomer-modified binder. Seemingly, in the case of plastomer/bitumen blend, the propensity to low-temperature cracking is to a great extent controlled by the corresponding base bitumen. The plastomer based mixture had improved permanent deformation performance, whereas the elastomers afforded a tangible amelioration for the vulnerability to load and non-load associated cracking. The SBS based mixture showed highest low-temperature fracture energy compared to the EVA based mixture. Despite the determinantal effect of age-hardening to low and intermediate temperature-related cracking of mixes, the results confirmed that the elastomeric materials can retard the impact of aging level on the low temperature and fatigue cracking. Comparision of results was justified by the statistical analysis in order to determine the significance of bituminous material parameters on the measured properties.

Comparative evaluation of ageing effects on the properties of regular and highly polymer modified asphalt binders

The use of polymer modified asphalt is steadily growing due to the increasing loading demands in asphalt pavements. Although common polymer modification doses range between 2.5 and 3.5% by weight of asphalt binder, higher dosages are being increasingly used to enhance the performance and durability of asphalt mixtures. These higher doses range between 7 and 8% by weight of asphalt, and the resulting binders are denoted as highly or heavily modified asphalts (HiMA or HP). The objective of this work is to characterize and compare different fundamental material properties and the expected mechanical performance of a regular polymer modified and a HiMA asphalt at the binder and mastic levels, under different ageing conditions. The results confirm an enhanced expected long-term mechanical performance of the HiMA asphalt in road projects as compared to conventional polymer modified binders.

Rheological properties of aged bitumen rejuvenated by polymer modified bio-derived rejuvenator

In this paper, a polymer modified bio-derived rejuvenator (PMBR) consisting of bio-oil, polymer modifier, and other additives (plasticizer, cross-linking agent) was investigated. The regeneration performance of PMBR on aged base and SBS modified bitumen was compared with that of commercial rejuvenator (CR) and bio-based rejuvenator (BR). The anti-cracking, anti-fatigue, anti-rutting and anti-moisture performance of aged base and SBS modified bitumen rejuvenated by CR, BR, as well as PMBR were evaluated via Dynamic Shear Rheometer (DSR) tests. The morphology, as well as the change of molecular functional groups of aged base and SBS modified bitumen rejuvenated by PMBR were studied by Fluorescence Microscopy (FM) and Fourier Transform Infrared Spectrum (FTIR). Glover-Rowe diagram results manifest that PMBR could restore the anti-cracking performance of aged bitumen to the level of virgin binder. Black diagram results show that PMBR rendered satisfactory elastic performance. Moreover, it is obtained from Linear Amplitude Sweep (LAS) results that PMBR performed better than conventional rejuvenators in reducing the damage rate and increasing the Nf of aged bitumen. Additionally, Multiple Stress Creep Recovery (MSCR) results reveal that PMBR contained no severe side-effects on the high temperature performance, and rendered better elastic recovery to aged bitumen. The Shear Test results show that PMBR rejuvenated bitumen contained better anti-moisture ability as well as better network structure strength among all rejuvenated bitumen. Finally, the reaction between PMBR and aged SBS modified bitumen and the restoration of network structure was revealed via analyzing the morphology studied by the FM test, and characterizing the the C─S stretching vibrations and ─CH═CH─ vibrations in polybutadiene block obtained from the FTIR test. It is verified that the polymer and crosslinking agent replenished by PMBR reacted with the originally destroyed SBS segment in aged SBS modified bitumen. Then the network structure was restored, which could explain the rheological properties of aged bitumen rejuvenated by PMBR.

Multiscale evaluation of the effect of recycled polymers on the long-term performance of bituminous materials

The use of recycled polymers as bitumen modifiers contributes to extending their application at a competitive cost being also a more sustainable solution. However, despite several studies proving their benefits in asphalt mixtures, their use is not yet widespread. Hence, this research explored the long-term performance of bituminous materials made with two of the most common recycled polymers (household polyethylene and a combination of polyethylene and crumb rubber). To achieve this, fatigue cracking, ageing and environmental effects (i.e. moisture and temperature susceptibility) were evaluated at the most significant scales (microstructure, bitumen, mortar and asphalt mixture) through: Atomic Force Microscopy (AFM), Multiple Stress Creep and Recovery (MSCR), Dynamic Mechanical Analysis (DMA) and UGR-FACT tests. Results proved that recycled polymers (especially for LDPE and Crumb Rubber combination) represent an improvement in durability at the binder level that thrives at all the scale levels tested thus providing greater confidence to extend its use.

Briquetting of mango seed shell: effect of temperature, pressure and binder

Mango peel and stone are the major process wastes of mango processing industry. In this study, an attempt was made to explore the economic potential and operational feasibility of outer hard fibrous pericarp of mango stone as a source of energy by adopting briquetting technology. Mango seed shell briquettes were prepared using hot and cold compression techniques to evaluate the influence of temperature (100 and 150°C), applied pressure (150 and 200 kg.cm-2) and binder level (sodium silicate: 15 and 20%). Properties of the briquettes such as density, durability, shatter indices and calorific value were determined. The briquettes produced by hot compression have the maximum and minimum densities of 1281 and 1184 kg.m-3, respectively. On the other hand, corresponding values in cold compression were 1127 and 1032 kg.m-3, respectively. Durability ranged from 88.04 to 94.31% in hot compression, while the range was 85.93 to 91.09% in cold compression. Among the two methods, maximum per cent (95.21%) weight was retained by the briquettes made by hot compression with high temperature and pressure combinations. The calorific value of mango stone shell was found to be 4468.67 kcal.kg-1. Minimum calorific value of 3546.23 kcal.kg-1 was noticed when briquettes were made with 20% binder level. High calorific value with good stability and durability of mango seed shell briquettes reflected its potential as a feasible energy source.

Performance of Aged Asphalt Binder Treated with Various Types of Rejuvenators

High demand for asphalt binders in road construction verifies the need of finding alternative materials through asphalt pavement recycling. This paper investigated the impact of different rejuvenators on the performance of an aged asphalt binder. Virgin Olive oil, virgin cooking oil, waste cooking oil, virgin engine oil, and waste engine oil were added to a 30/40 penetration grade aged asphalt binder at a fixed oil content of 4% for all types. The wet method was used to blend the rejuvenators and aged asphalt binder. The physical, rheological, and chemical properties of the rejuvenated asphalt binder were evaluated using several laboratory tests which include penetration, softening point, bleeding, loss on heating, storage stability, penetration index, ductility, viscosity, dynamic shear rheometer, and Fourier transform infrared spectroscopy. The outcomes of the physical properties showed that the olive, waste, and virgin cooking rejuvenators can restore the aged asphalt binder to a penetration grade of 60/70. In contrast, the virgin and waste engine oil required a more quantity of oil to rejuvenate the aged asphalt binder. A sufficient amount of rejuvenator could regenerate the (G*/sin δ), (δ°), and (G*) for the aged asphalt binder. The addition of virgin olive and cooking oils in aged asphalt led to a rutting issue. No chemical reactions were observed with the addition of rejuvenators but they give an impact on reducing the oxidation level of the aged asphalt binder. As a result, further research should be performed on waste cooking oil given that it is inexpensive and provides excellent performance results. Doi: 10.28991/cej-2021-03091669 Full Text: PDF

IMPACT OF PELLET BINDER ON BROILER PERFORMANCE AND FEED PROCESSING ECONOMICS

Total number of 216 one-day-old, unsexed Hubbard broiler chicks were used to study effects of pellet binder level together with pelleting diameter on growth performance, carcass measurements, and economic efficiency. Experimental birds were distributed over 6 groups, each group comprised of 36 chicks in 6 replicates of 6 chicks each. The experimental dietary treatments were as follows: control (T1) basal diet (BD) that is pelleted in standard diameter (SD) with addition of calcium lignosulfonate (CL) 2 Kg/ Ton; (T2) BD pelleted in SD with CL 4 Kg/ Ton; (T3) BD pelleted in SD with CL 8 Kg/ Ton; (T4) BD pelleted in a diameter thicker that SD by 1.0 mm (SD+1) with CL 2 Kg/ Ton; (T5) BD pelleted in SD+1 with CL 4 Kg/ Ton; and (T6) BD pelleted in SD+1 with CL 8 Kg/ Ton. Obtained results showed that all parameters of growth performance; live body weight (LBW), daily weight gain (DWG), daily feed consumption (DFC), and feed conversion ratio (FCR) were not significantly affected (P>0.05) by dietary treatments. Also, values of growth efficiency; relative growth rate (RGR),performance index (PI), production efficiency factor (PEF), protein conversion ratio (PCR), and energy conversion ratio (ECR) indicated no significant differences (P>0.05) within all tested groups. Moreover, data of carcass traits; dressed carcass, abdominal fat, giblets, total edible parts appeared significantly similar (P>0.05) among all treatments. Additionally, data of economic evaluation showed better economic efficiency with T2, T5, or T6 groups when compared to other groups. It could be concluded that using CL as a pellet binder in SD conditions, could be more beneficial with inclusion level of 4 Kg/Ton. Moreover, it might be advised to include CL at 8 Kg/ Ton in diets only when pelleting feedatSD+1 as these conditions positively maintained performance and carcass of birds.

Prevalence of aflatoxin b1 in some common poultry feed ingredients and optimum inclusion levels of mycofix binder as feed additive on performance of broiler chickens chickens

A preliminary study was carried out to determine the prevalence of Aflatoxin B1 (AfB1) contamination and common moulds growing in some selected poultry feed raw materials in Zaria. Five different feed raw materials:Maize (MZ), soybean cake (SBC), groundnut cake (GNC), brewers dried grain (BDG) and maize offal (M/O), were collected from four feed mills and the open market. The common moulds isolated from the samples were Mucor spp., Aspergillus spp., Fusarium spp., Penicillum spp., Curvularia spp. and Rhizopus spp. AfB1 contamination showed that maize and soya bean cake were less than the 20 parts per billion (ppb) permissible limits for AfB1 in poultry feed ingredients, while BDG, M/O and GNC were 40, 60 and 80 % respectively above 20 ppb permissible limits. A feeding trial was conducted to evaluate the response of broiler chickens to Mycofix a toxin binder. Three hundred and thirty Ross, 1-day old broiler chicks were assigned to five dietary treatments, each with three replicates of 22 chicks per replicate in a completely randomized design (CRD). Treatment 1 was the control diet without Mycofix while treatments 2, 3, 4 and 5 had Mycofix included at 100, 200, 300 and 400 g /100kg diet, respectively at both starter and finisher phases. Experimental diets and water were given to the birds ad libitum during eight weeks of the feeding trial. Data were subjected to Analysis of Variance (ANOVA) using General Linear Model procedure of SAS and significant differences among treatment means were compared using Dunnette test of significance. Results of the starter phase showed that birds fed 400 g/100kg Mycofix diet had the best final body weight (902.67g), weight gain (839.67g) and average daily weight gain (29.98g). Birds fed 200 g /100 kg Mycofix had the lowest feed conversion ratio of 1.6 and the least cost per kilogram gain(₦138.52).At the finisher phase birds on 400 g/100kg Mycofix diet had the best final weight (2345.3g), weight gain (1403.3g), average daily gain (50.1g), feed conversion ratio (2.1) and least feed cost per kilogram gain (₦167.20). It may be concluded that addition of Mycofix to diets of broiler chickens at 400g/ 100kg at both starter and finisher phases of the study improved performance significantly and gave the least cost of production.

Determination of Selected Texture Features on a Single-Layer Grinding Wheel Active Surface for Tracking Their Changes as a Result of Wear.

Measurements of the active surface microgeometry of the grinding wheel by contact and optical methods are commonly used to obtain a cloud of points representing the surface of the examined tool. Parameters that can be determined on the basis of the above-mentioned measurements can be universal parameters, which are commonly used to assess the geometric structure of a surface or parameters taking into account specific properties of the grinding wheel active surface (GWAS) structure. This article proposes a methodology for determining the average level of binder, which allows the definition the cut-off level required to separate from the measurement data: (i) the areas representing grains, (ii) the areas of gumming up of the grinding wheel, and (iii) deep cavities in approximately the same places on the investigated grinding wheel, regardless of the degree of its wear. This, in turn, allows one to track changes in characteristic parameters computed from measurements of texture in the above-mentioned areas due to different GWAS wear processes. The research was based on the analysis of data obtained from measurements of single-layer grinding wheels using the replica technique. The adopted measurement methodology enables measurement of approximately the same (94% coverage) areas of the GWAS at four stages of grinding wheel operation. Errors that were computed related to the determination of the volume of abrasive on the GWAS at various stages of wear using the developed methodology were lower, on average, by 48% compared to the automatic recognition of islands made with a commercial software.

Enhancing Biomass Value Chain by Utilizing Biochar as A Free Radical Scavenger to Delay Ultraviolet Aging of Bituminous Composites Used in Outdoor Construction

This study examines the merits of using biochar to delay aging in construction while promoting the economic viability of biofuel production and enhancing the biomass value chain. Biochar residue from pyrolysis of biomass to biofuel was introduced to neat asphalt and rubberized asphalt binders. The study results showed biochar can delay oxidation and UV-induced aging at binder and mixture level as evidenced by lowering rheological and chemical aging indexes. The rheological aging index was measured based on the change in crossover modulus due to aging, and the chemical aging index was measured based on the change in carbonyl and sulfoxide functional groups due to aging. Four types of aging were examined including oxidation and UV aging at the binder level as well as aging and weathering at the mixture level. In terms of oxidation aging, biochar was more effective for rubberized asphalt, while in the case of UV aging, neat asphalt appeared to benefit more than rubberized asphalt from the presence of biochar. The latter can be attributed to the role of biochar as a UV-light blockage and free radical scavenger. Rubberized asphalt inherently contains carbon black which enhances the internal resistance against UV aging, hence the role of biochar was not as significant in rubberized asphalt compared to that of the neat asphalt. However, in the case of oxidation aging, biochar noticeably improved the rubberized asphalt compared to neat asphalt. The study outcomes provide a simultaneous solution to promote resource conservation and enhance aging resistance of bituminous composites. Biochar, carbonaceous particles, made from biowaste can be used as a free radical scavenger to delay ultraviolet aging of bituminous composites. Therefore, this study promotes sustainability by creating applications for biochar while increasing pavement durability by delaying asphalt aging.

Effect of binder, lubricant and compression force levels on hardness and disintegration time of immediate release tablets with a high-dose API - a 33 full-factorial design

Effect of binder, lubricant and compression force levels on hardness and disintegration time of immediate release tablets with a high-dose API - a 33 full-factorial design

High-Performance Sustainable Asphalt Mixtures for High-Volume Traffic Roads in Severe Climates

This paper summarizes the work carried out in a research project whose main objective was to develop high-performance sustainable bituminous materials (using crumb rubber and additives to reduce their manufacturing temperature) to be used in roads that support high traffic volumes and/or severe environmental conditions. For this purpose, various studies were conducted both in a laboratory and in a real asphalt plant (at binder and mixture level). Later, these materials were used to construct a trial section in a highway at a mountain pass (at more than 1400 m above sea level) supporting more than 2600 heavy vehicles each day under severe environmental conditions (snow during winter, and high temperatures and many hours of solar radiation during the summer). The results indicate the viability of using these materials, since they provide a number of advantages such as improved workability at lower temperatures and an increase in the mechanical resistance against the main sources of distress that affect asphalt pavements.

Do all rejuvenators improve asphalt performance?

Reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) contain significant amounts of bitumen and their application in new constructions have been promoted as a sustainable practice in the pavement industry and to promote circular economy. However, this effort has faced challenges such as the aged bitumen’s inferior properties compared to the virgin counterpart and its unknown contribution to new pavements. To address the latter issue, liquid additives were used under the general title of rejuvenators. That poses an additional challenge associated with the lack of clear metrics to differentiate between softeners and rejuvenators. While revitalising aged asphalt binder to regain its desirable properties would be an ideal solution, progress in this area has been limited by a lack of understanding of rejuvenation mechanisms at the molecular level and the absence of representative test parameter(s) to evaluate both efficacy and durability of rejuvenators. In this study, both laboratory experiments and computer modelling were combined to not only compare efficacy of several rejuvenators, but also explain why some rejuvenators are effective while others are not. It was found that all studied rejuvenators have a softening effect on aged asphalt, but only a few of them revitalised aged asphalts’ physicochemical and rheological properties at the binder level. At the mixture level, a lower number of gyratory compaction and reduced rate of crack propagation were observed after the addition of high performing rejuvenators to the asphalt mixtures containing RAP. The reduction in crack propagation rate could be attributed to both enhanced blending between an aged and virgin bitumen and the revitalisation of aged bitumen properties. The latter phenomenon was explained at the molecular level based on the rejuvenator’s ability to interact with aged asphaltene molecules intercalating into and separating asphaltene nanoaggregates. Accordingly, this molecular-level phenomenon is reflected in two ways: an increase in crossover modulus and crossover frequency at the binder level, and a reduced crack propagation rate at the mixture level.