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In recent years, the food industry has become increasingly involved in researching vegetable fats and oils with appropriate mechanical properties (ease of transport, processing, and storage) and a specific lipidic composition to ensure healthy products for consumers. The chemical–physical behavior of these matrices depends on their composition in terms of single fatty acids (FA). However, as we demonstrate in this work, these properties, as well as the absorption, digestion and uptake in humans of specific FAs, are also largely determined by their regiosomerism within the TriAcylGlycerols (TAG) moieties (sn-1,2,3 positions). The goal of this work is to study for the first time vegetable fats obtained directly from a sample of natural cocoa butter (CB) through a process that manipulates the distribution of FAs but not their nature. Even if the initial percentage of each FA in the mixture remains the same, CB derivatives seem to show improved chemical–physical features. In order to understand which factors account for their physical and chemical characteristics, and to check whether or not the obtained new matrices could be considered as valid alternatives to other vegetable fats (e.g., palm oil (PO)), we carried out an experimental investigation at both the macroscopic and molecular level including: (i) Differential Scanning Calorimetry (DSC) analyses to examine thermal features; (ii) rheological testing to explore mechanical properties; (iii) powder X-ray diffraction (PXRD) to evaluate the solid-state phases of the obtained fats; and (iv) 1H and 13C Nuclear Magnetic Resonance (NMR, 1D and 2D) spectroscopy to rapidly analyze fatty acid composition including regioisomeric distribution on the glycerol backbone. These last results open up the possibility of using NMR spectroscopy as an alternative to the chromatographic techniques routinely employed for the investigation of similar matrices.

Physical and chemical indicators of bitumen quality of grade BND 70/100 with the added carbon nanopowder 2% by weight have been studied by laboratory test methods and analysis. High reaction ability of nanopowder particles and concentration of excess surface and internal energy in them have been determined, which provide the increase of low-temperature resistance, aggregate strength, and improvement of rheological properties of nanostructured bitumen. Essential structure variation has been proved: the increase of asphaltenes and oils content for 9% and 7.2% respectively due to the decrease of resins for 16.2% by weight. Methods have been discussed for preparing a liquid nanocarbon mix, adding of the mix into bitumen and homogenization of the bitumen. Some economic indicators have been represented which influence essentially the reduction for the cost value of the nanostructure bitumen.

ILT is particularly useful when the signal is characterized by multi-exponential decay, for example in spin relaxation or in the dephasing of the NMR spin echo signal associated with sopra molecular aggregation under the influence of pulsed magnetic or internal field gradients. As novel approach to observe the real rejuvenating effect of the potential additive, an Inverse Laplace Transform of the NMR spin-echo decay (T2) was applied. The potentialities of a new, non-toxic and eco-friendly biocompatible additive on aged bitumen are explored for the first time as bitumen rejuvenator, by means of advanced rheological and Relaxometry-NMR measurements. Pristine, aged, and doped aged bitumen morphology have been investigated by SEM. The new rejuvenator helps to rearrange the structure of the aged bitumen (aiming at the original one), and this mechanism can be observed by ILTNMR analysis.

An experimental research has been done investigating the effects of the addition of multi-walled Carbon Nanotubes (CNTs) on the rheological behaviour of bitumen and its microstructure. two different types of CNT have been tested, consisted of a product obtained by laboratory synthesis through Catalytic Chemical Vapour Deposition (CCVD) technique and a commercial one, hereinafter are called type 1 and type 2, respectively. Both types of CNTs were completely characterized in terms of morphological, chemical, and structural properties. In addition, the rheological analysis were also conducted on bitumen blends containing CNT providing a complete study understanding the effectiveness of introduced CNT compared to those of commercial ones as for bitumen modification. For this purpose the experimental plan consisted of Trasmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), micro-Raman spectroscopy, and rheological analysis in oscillatory regime.

A series of Fibre-added bitumen compounds were subjected to conventional and rheological tests for investigating the effectiveness of modified fibres in improving the characteristics of bituminous binders. The studied fibres were novel composite cellulose-based poly-functional fibres with and without a plastomeric polymer and crumb rubber content, which blended with neat bitumen or SBS Polymer modified Bitumen (PmB). The test program included a primary stage of microscopic analysis by means of Scanning Electron Microscopy (SEM), for observing these composite fibres’ microstructure as well as the empirical test methods, and dynamic rheological analyses using Dynamic Shear Rheometer (DSR). According to the conventional test results, the addition of fibres increased the softening point and viscosity and reduced the penetration. From another perspective, while the addition of rubber decreased the softening point and viscosity, it increased the penetration of compounds in comparison to those containing fibres without rubber content. From the results obtained by Multiple-Stress Creep-Recovery (MSCR) and Frequency Sweep (FS) test, the isochronal graphs of complex modulus and creep-recovery curves showed the same trends in terms of increased stiffness. In addition, the phase angle curves confirm that the presence of rubber decreased the stiffness and increased the elasticity for PmB compounds in comparison to those of reference mixtures containing non-rubberized fibres.

Over the years, the need for the synthesis of biodegradable materials has facilitated the drift of the asphalt industry towards eco-sustainable and cost-effective production of road pavements. The principal additives in the asphalt industry to improve the performance of road pavements and increase its lifespan are majorly rheological modifiers, adhesion promoters and anti-oxidant agents. Rheological modifiers increase physico-chemical properties such as transition temperature of asphalt binder (bitumen), adhesion promoters increase the affinity between binder and stone aggregates while anti-oxidant agents reduce the effects of oxidation caused by exposure to air, water and other natural elements during the production of asphalt pavements. In this study, we tested the effectiveness of a food grade bio-additive on these three aforementioned properties. We also sought to hypothesize the mechanisms by which the additive confers these desired features on bitumen. We present this study to evaluate the effects of turmeric, a food-based additive, on bitumen. The study was conducted through dynamic shear rheology (DSR), atomic force microscopy, scanning electron microscopy (SEM) and boiling test analysis.

For asphalt concrete preparation in laboratory mix-design operations, bitumens are usually mixed with micrometer-sized particles (filler), sand and centimeter-sized crushed stones in a gyratory press at a temperature of about 140&ndash, 155 &deg, C depending on the bitumen viscosity, until adequate homogenization and compaction take place (air voids optimum). This requires energy consumption. To minimize it, the process needs to be optimized and is usually made empirically. The aim of this manuscript is to gain a comprehension of the physico-chemical mechanisms involved in the process by exploring: (i) the rheological properties (viscosity, activation energy) of a neat and RTFOT-aged bitumen, in presence and in absence of a filler, (ii) the volumetric and resistance behavior under the compaction in a standard Gyratory Compactor (GC) of their blends with aggregates and (iii) the mechanical properties (Indirect Tensile Strength, compression and tensile deformation) of the final products. Correlations between activation energy and pre-exponential factor of the viscosity on a side, and between viscosity, workability and final mechanical properties on the other side allowed to provide a rational interpretation of the physico-chemical processes involved in the framework of the physics of complex fluids. The scientific clues will be of help in optimizing the workability in asphalt concretes productions with obvious repercussions in terms of energy savings, useful for economic and environmental issues.

The aim of this investigation was to prepare two solid mixtures containing a soluble polymorph of (+)-catechin and mucic (MUC) or tartaric (TAR) acids as new leavening agents. The solid mixtures were based on a polymorph of (+)-catechin, characterized through Powder X-ray Diffraction (PXRD) analysis and assayed in in vitro antioxidant and solubility assays. The dough samples were studied by dynamic rheological tests, while muffins were studied through Headspace Solid-Phase Microextraction (HS-SPME)/ Gas Chromatography-Mass Spectrometry (GC-MS) analysis to identify volatile compounds, in vitro tests to evaluate antioxidant properties, and sensory analyses. TAR powder showed a solubility in water almost one order of magnitude increased with respect to commercial (+)-catechin (40.0 against 4.6 mg mL&minus, 1) and increased antioxidant performances. In particular, TAR showed total phenolic content (TPC) and total antioxidant capacity (TAC) values of 0.0298 &plusmn, 0.021 and 0.0081 &plusmn, 0.0009 meq CT/g, while MUC showed better results in terms of 2,2-diphenyl-1-picrylhydrazyl) acid (DPPH) and 2,2&prime, azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 0.518 &plusmn, 0.015 and 0.112 &plusmn, 0.010mg/mL, respectively. MS analysis identified different compounds derived from the lipid oxidation process. Muffins obtained using both powders showed interesting outcomes regarding dough process and appreciable appearance/olfactory/taste/texture profiles. Muffins obtained from TAR-based mixture showed also a total phenolic content of 0.00175 meq CT/g muffin, and almost two times improved TAC and scavenger activity against DPPH radical. The formulated powders could be used as suitable health-promoting ingredients in the food industry.

Asphalt concretes are materials used worldwide. It is well-known that in such materials the minor component, the bitumen, plays the most important role since it binds the high fraction (>95%) of inorganic macrometer-sized particles ensuring a coherent material fit for uses in road pavement. Additives can be used to increase the overall rheological properties, with high benefits in terms of resistance to mechanical stress and to ageing. Among these, nanoparticles have recently been considered as very effective additives in increasing the overall performance, increasing the viscosity, the rutting parameter and the recovery from deformation. However, they are expensive, so a delicate equilibrium between costs and benefits must be found for large-scale uses. In this framework, we furnish our critical analysis of the state-of-the art technologies used for improving the bitumen performances by means of nanoparticles with an eye to eventual added-values (like anti-oxidant effect, antistripping properties, or UV radiation screening which avoids radiation-induced ageing…). We will critically consider the costs involved in their use and we will give our opinion about vanguard techniques which can be fit for the analysis of nanoparticles-containing bitumens and asphalts. Interesting perspectives will be also given for future research and applications.

Asphalt concretes are biphasic systems, with a predominant phase (c.a. 93-96% w/w) made by the macro-meter sized inorganic aggregates hold together by small amounts of a viscoelastic binding bitumen (c.a. 5%). Even if the bitumen is in minor amount, it plays an important role dictating all the desired properties: rheological performances, resistance to aging etc. What happens if nanoparticles are used as additive in such materials? They usually confer enhanced resistance under mechanical stress and give sometimes interesting added-values properties so, despite the high costs of their production, nanoparticles are interesting materials which are being monitored for large scales applications. This work introduces the reader to the properties of nanoparticles in an easy to review their use in bitumen and asphalt preparation. Silica, ceramic, clay, other oxides and inorganic nanoparticles are presented and critically discussed in the framework of their use in bitumen and asphalt preparation for various scopes. Organic and functionalized nanoparticles are likewise discussed. Perspectives and cost analysis are also given for a more complete view of the problematic, hoping this could help researchers in their piloted design of material for road pavements with ever-increasing performances.

This paper evaluated the potentialities of a green and biocompatible rejuvenator agent (HR) in conferring an appreciable resistance against the effects caused by artificial aging on a given bitumen. Both neat and aged bitumens were analyzed and compared to analogous samples modified with HR. Control samples containing a vegetable oil as softening agent were also tested for comparison. The tested samples were subjected to a second aging cycle. Structural differences between the samples were carried out through an inverse Laplace transform of the NMR spin-echo decay (T2) and self-diffusion measurements by pulsed gradient spin echo nuclear magnetic resonance (PGSE-NMR) spectroscopy. In addition, dynamic rheological analyses were conducted to determine the dependence of the gel-sol transition temperature on both the type of additive and ageing process. The present study clearly highlighted the fact that artificial ageing, realized here by the rolling thin film oven test (RTFOT) and the pressure ageing vessel (PAV) test, induced important structural modifications. The analysis of relaxation times and self-diffusion coefficients indicated that ageing promoted the formation of molecular populations characterized by a shift of the distribution toward higher molecular weights compared to unaged bitumen. Diffusion data showed also an Arrhenius-like temperature dependence. A correlation between all the data was attempted to understand the role of the investigated additives. The eco-friendly biocompatible rejuvenator helped not only to restore the structure of the aged bitumen, but even slowed down the processes of a second aging (aiming at the first aged sample).

Tuning the rheological properties of bitumens is extremely important for applicative purposes. This can be achieved by the use of chemical additives tuning the asphaltene-asphaltene and asphaltene-maltene interactions. We propose the use of an epoxy-resin to give more rigid and thermally stable bitumens on the basis of its tendency to form polymeric networks which would bridge asphaltene clusters. Rheometry confirmed this hypothesis and showed that a load of epoxy-resin as low as 0.1% gives the highest rigidity. Atomic Force Microscopy highlighted the structural changes at the basis of the observed effects. The small amount of epoxy resin needed and its low-cost are elements deserving monitoring.

The use of recycled bitumen (such as the Recycled Asphalt Pavement, RAP) in production of new pavements is becoming an important issue, owing to the potential economic and environmental benefits derivable from the replacement of virgin materials with recycled ones. Nevertheless, the properties of RAP negatively affect the final behavior of pavement, reducing, therefore, its practical use. With the aim of modifying RAP behavior, rejuvenating additives are often used; anyway, their effects have to be carefully studied, according to the properties of both RAP and virgin bitumen. In this work, simulated aged bitumens were used to test the effects of two rejuvenating agents; rheological fundamental tests in steady and dynamic condition were carried out in a wide range of temperature using both shear and extensional kinematic conditions with the aim of investigating material behavior and additive effects both at high and low temperature. Moreover, the bitumen microstructure was investigated with Nuclear Magnetic Resonance (NMR) to better understand the change in material behavior. The rheological characterization has shown itself able to evidence the changes caused by simulated long- and short-term aging. Moreover, the positive effects of additives were highlighted at both high and low temperature and the rheological results were confirmed by NMR characterization showing that the most promising agent is able to restore a structure, based on asphaltene and maltene phases, very similar to those of the short-term aged system and virgin material.

In this paper the properties of a new modified bitumen with crumb rubber (CR) additive and stabilising surfactants (a fatty acid – FA and an organosilane OS) are investigated. The characterisation ...

The performances of a modified bitumen as a function of the concentration of an added organosilane modifier was examined in terms of its consistency, adhesion and rheological properties. In particular, the modifier guarantees excellent performance at 0.01 wt% loading, and almost complete resistance to water at 0.03 wt% loading. A quantitative evaluation of the modified bitumen’s performance was carried out by a contact angle test. Moreover, SEM/EDS analysis showed that the organosilane modifier was able to penetrate the surface of the stone, thus aiding anchoring of the binder to the surface.

Bitumens are composite materials whose complex organization hinders the rational understanding of their relationships between composition, structure and performances. So, research attempting to shed more light in this field is required. In this work Wide Angle X ray Scattering (WAXS) has been used to explore the influence of six opportunely chosen additives on the bitumen structure with the aim to ultimately correlate the findings with the bitumen performances. Diagnostic fingerprints have been observed in the WAXS profile: asphaltenes form stuck of about 18 A and constituted by about 6 asphaltene units on average. Such stucks are, in turn, organized at higher levels of complexity forming anisotropic aggregates of about 200 A × 28 A which, again, are assembled to form micrometer-size elongated aggregates characterized by the so-called bee-structure. The structural effects of the six opportunely chosen additives (Organosilane, Polyphosphoric, Phospholipids, Acetamidophenol, Oleic Acid, octadecylamine) have been pointed out and, corroborated by AFM images, have been correlated with the rheological behavior and justified at the microscopic level: additive with an apolar nature are preferentially located in the maltene phase weakening asphaltene inter-clusters interactions and softening the bitumen, whereas, on the contrary more polar additives act in opposite directions. Peculiar behavior have been unveiled in the case of amphiphilic additive due to the simultaneous presence, within their molecular architecture, of both polar and apolar moieties. The knowledge of the detailed effect of appropriately chosen additives on the nanoscopic and mesoscopic structure and their correlation with the rheological properties constitute the first step for opening the door to the piloted design of new bitumens with desired properties for ad-hoc uses.

Polymer modified bitumen (PMB) is used extensively in thin asphalt surfacing and seals in order to improve specific performances. However, the performances of PMB are not easy to demonstrate with the conventional methods, such as penetration test, softening point etc. In order to a better evaluation, different characterization methods are needed rather then ordinary empirical rheological tests. This work deals with the characterization of linear copolymer styrene–butadiene–styrene (SBS) and SBS + polyphosphoric acid (PPA) modified bitumen by using conventional as well as advanced methods on bitumens at different ageing steps and temperature. Fundamental rheological tests, based on a state of the art dynamic shear rheometer in the temperature range from −30 °C to +160 °C and advanced 1 H magnetic resonance relaxometry analysis to evaluate the effect of modifiers on the bitumen structure, were used. Moreover, morphological analysis by scanning electron microscope (SEM) was performed on neat and modified bitumen and the effect of the filler addition on the supra-molecular organization of the bituminous binder was also investigated.

In the asphalt industry, bituminous emulsions are widely used in road pavement operations and in building/construction processes such as cold mix asphalt and waterproofing processes, respectively. A very important fact to keep in mind is that not all types of bitumen are suitable for the realization of bituminous emulsions. This is largely due to the variation in their chemical nature and the different cracking processes carried out on the bitumen during the fractional distillation process in the petroleum industry. The objective of this study is to identify the underlying causes of the non-emulsionability of bitumen using Nuclear Magnetic Resonance (NMR) and Dynamic Shear Rheology (DSR) analysis. NMR analysis aims at identifying the fundamental chemical components that are responsible for the emulsionability of the bitumen binder and how important their role is in this phenomenon. On the other hand, the DSR analysis is aimed at determining if the rheological (viscoelastic) behavior of bitumen is implicated in its emulsionability. The indications gotten from the data produced by these techniques, enable us as soon as the analyzed bitumen is deemed non-emulsionable to identify what type of additive can be used to modify the bitumen and alleviate its non-emulsionability until a point where its chemical components become ideal for the realization of bituminous emulsions. In this research work, a model bitumen (labelled as Cimar) which is known for its excellently high emulsionability in the production of anionic bituminous emulsions was used as the reference sample. Two bitumens (labelled as Adriatica and Alma) which from preliminary testing were deemed non-emulsionable were alongside the additives selected and subjected to the aforementioned techniques for analysis on their emulsionability. The NMR data obtained allowed the identification of the chemical nature of the components of the analyzed bitumens and the design of the right additive which improves the bitumen and makes it suitable for the preparation of emulsions. In addition to these, a largely uncommon however effective method of acid number determination of bitumen gave indications on an underlying factor which largely influences the emulsionability of bitumen. An aliphatic and an aromatic surfactant were identified thanks to the spectroscopic findings in this study.

Bigels are biphasic systems formed by water-based hydrogels and oil-based organogels, mainly studied, in the last few years, for pharmaceutical and cosmetic application focused on the controlled delivery of both lipophilic and hydrophilic active agents. The rheological properties of bigels depend on both the amount and the rheological characteristics of single structured phases. Moreover, it can be expected that, at large fractions of one of the starting gels, systems more complex than oil-in-water or water-in-oil can be obtained, yielding bicontinuous or matrix-in-matrix arrangement. Model bigels were investigated from a microstructural (i.e. microscopy and electrical conductivity tests) and rheological point of view. The hydrogel was prepared by using a low-methoxyl pectin whereas the organogel was prepared by using olive oil and, as gelator, a mixture of glyceryl stearate and policosanol. Model bigels were obtained by increasing the amount of organogel mixed with the hydrogel, and microstructural characterisation evidenced an organogel-in-hydrogel behaviour for all investigated samples, even though at the highest organogel content a more complex structure seems to arise. A semi-empirical model, based on theoretical equations developed for suspensions of elastic spheres in elastic media, was proposed to relate bigel rheological properties to single phase properties and fractions.

Herein, the evaluation of the effectiveness of several adhesion promoters for asphalt according to the chemical and mineralogical nature of the stone was investigated. From research in the road construction sector, the most common types of activators present on the market are classified according to the chemical nature of their active ingredient: amides, polyphosphoric acid (PPA) esters and organosilanes. Therefore, for each of these families, the adhesive properties of the corresponding modified bitumen loaded with a fixed amount of active agent, were tested on four types of stone materials. X-Ray Powder Diffractometry (XRPD), X-Ray Fluorescence (XRF) and Environmental Scanning Electron Microscope Energy Dispersive Spectroscopy (ESEM–EDS) were carried out in order to establish the chemical and mineralogical nature and identify the agglomerate structures of the selected inert rocks. Among various screened products, the organosilane-based additive showed excellent adhesive performances, independently of the chemical composition of inorganic interfaces, as confirmed by both contact angle and boil test measurements. Conversely, basic nature activators such as amides and those with an acidic nature, such as the esters of PPA, were greatly affected by the type of mineral substrate. Finally, the effect of added adhesive agents on the viscoelasticity of modified bitumen was checked in the linear regime by oscillatory rheology. Differences in the adhesive properties observed among the tested classes of amphiphilic binders were discussed in terms of difference in the sizes of their respective head groups.

A study on the effect of silica nanoparticles (SNPs) dispersion in bitumen is herein reported. First, the size of the nanoparticles was finely tuned by controlling the experimental conditions during their synthesis, obtaining spherical SNPs with diameter ranging from 95 up to 900 nm. Subsequently, SNPs were embedded with peripheral amine groups by using APTES (3-aminopropyltriethoxysilane) as functionalized agent (NH2@SNP), and ultimately long alkyl chains were grafted by reacting the free amine with an alkylated aldehyde (C14N@SNP). All SNPs (ca. 1 wt%.) were dispersed in bitumen to probe their effect on the rheological properties of bitumen. No significant change in the thermorheological properties of bitumen was observed upon varying the size of the SNPs. Slight improvement was observed when using NH2@SNPs, while the best results were obtained by using C14N@SNPs, showing the crucial role that hydrophobic substituents play in bitumen binders which leads to significant improvements.

The functionality of a green additive, acting as bitumen rejuvenator was considered in the presented experimental work. The additive’s effects on aged bitumen have been investigated through advanced rheological and NMR-relaxometry measurements. Bitumen ageing encompasses volatilization and oxidation which enable changes in the material molecular structure. Volatilization occurs mainly at high temperatures during production, transport and laying of the asphalt concrete. The oxidation, also caused by atmospheric oxygen and UV radiation, leads to an increased fragility and development of cracks in the asphalt layer. Fresh, aged, and doped recycled bitumens were tested. Rheology and NMR have been used to assess the structural differences between the bitumens and to understand the role of the proposed additive. A real rejuvenator helps to rearrange the colloidal structure of the oxidized bitumen, thus recreating one similar to the fresh bitumen. As a novel approach to bitumen characterisation, an inverse Laplace transform of the NMR spin-echo decay (T2) was here applied.

Bitumen aging is the major factor which contributes to the deterioration of the road pavement. Oxidation and volatilization are generally considered as the most important phenomena affecting aging in asphalt paving mixtures. The present study was carried to investigate whether various antioxidants provided by natural resources such as phospholipids, ascorbic acid as well as lignin from rice husk, could be used to reduce age hardening in asphalt binders. A selected bituminous material was modified by adding 2 % w/w of the anti-aging natural additives and subjected to accelerated oxidative aging regimes according to the Rolling Thin Film Oven Test (RTFOT) method. The effects of aging were evaluated based on changes in sol-gel transition temperature of modified bitumens measured through Dynamic Shear Rheology (DSR). Moreover, changes of Electron Paramagnetic Resonance (EPR) spectra were monitored on the bituminous fractions asphaltene and maltene separated by solvent extraction upon oxidative aging. The phospholipids-treated binder exhibited the highest resistance to oxidation and the lowest age-hardening effect compared to the other tested anti-oxidants. The combination of EPR and DSR techniques represents a promising method for elucidating the changes in associated complex properties of bitumen fractions promoted by addition of free radical scavengers borrowed by green resources.

Bitumen has unique chemo-mechanical properties, and for this reason, it is today one of the main constituents of many industrial products beside its common use in highway pavements construction. While the excellent rheological properties of bitumens have been investigated by means of different techniques, much remains to be known about the intrinsic properties of this complex material. It is therefore important to investigate its structure and properties from a closer point of view, towards possible useful modifications of the neat material. The present research developed a technique to investigate the composition of bitumens using Thin Layer Chromatography (TLC) to separate the different fractions, and Nuclear Magnetic Resonance (NMR) spectroscopy to assess and quantify the aliphatic hydrogen part with respect to the aromatic part. To achieve a comprehensive understanding of the chemical composition of the materials, Proton Nuclear Magnetic Resonance (1H-NMR) analysis was conducted in solution, using CCl4 as solvent, on three different neat bitumens and on their asphaltene and maltene fractions. The combined application of TLC and 1H-NMR spectroscopy enables the advanced characterization of bitumens supplied from different sources or obtained from different processes. This further allows addressing the use of specific modifications according to the bitumen final applications.

A good adhesion between bitumen, the common binder used in the construction of pavements, and mineral aggregates is a key property for optimal performance of the road paving material (asphalt). Moreover, as bituminous material is viscoelastic in nature, an improvement of its mechanical response does represent an equally important factor in the design of roads. To date, a variety of chemical compounds has been tested as bitumen modifiers and evaluated in their capacity to improve the adhesion of binder to the aggregates and promote an increase of the bitumen softening point, especially in warm ambient conditions. This contribution explores, for the first time, the potentialities of a class of lipophilic food grade additives, i.e., non-toxic and eco-friendly biocompatible compounds, acting both as adhesion promoters and as rheological modifiers. Their effects on the high temperature mechanical performance of a tested bitumen have been investigated through time cure rheological measurements and the sol-transition temperature determined in a wide range of temperatures. Measurements of the contact angle between the aggregate surface and modified bitumens preventively blended with increasing amounts of food grade additives were also carried out. We believe that those results could provide an alternative opportunity to use additives from natural resources in the design of sustainable and much more performant asphalts.

Due to the wide variation in geographic and climatic conditions, the search for high-performance bituminous materials is becoming more and more urgent to increase the useful life of pavements and reduce the enormous cost of road maintenance. Extensive research has been done by testing various bitumen modifiers, although most of them are petroleum-derived additives, such as polymers, rubbers and plastic, which in turn do not prevent oxidative aging of the binder. Thus, as an alternative to the most common polymeric rheological modifiers, selected binder additives falling in the categories of organosilane (P2KA), polyphosphoric acid (PPA) and food grade phospholipids (LCS) were homogeneously mixed to a base bitumen. The goal was to analyse the micro-morphology of the bitumens (neat and modified) subjected to different cooling rates and to find the corresponding correlations in the mechanical response domain. Therefore, microstructural investigations carried out by Atomic Force Microscopy (AFM) and fundamental rheological tests based on oscillatory dynamic rheology, were used to evaluate the effect of additives on the bitumen structure and compared with pristine binder as a reference. The tested bitumen additives have been shown to elicit different mechanical behaviours by varying the cooling rate. By comparing rheological data, analysed in the framework of the “weak gel” model, and AFM images, it was found that both P2KA and PPA altered the material structure in a different manner whereas LCS revealed superior performances, acting as “mechanical buffer” in the whole explored range of cooling rates.

The rheological properties of bitumens can be modified by the addition of specific chemical additives. Taking into account the molecular complex aggregation pattern, we hypothesized that macromolecules characterized by long, flexible, and hydrophilic chains can establish soft bridges connecting the different polar aggregates of asphaltenes, strengthening their overall hierarchical supra-structures, and consequently increasing rheological performance at higher temperatures. Here, we propose the use of low cost and high availability polysaccharides as chemical additives to improve the rheological characteristics of a bitumen and to strengthen its thermal resistance. Fourteen different low-cost and high-availability polysaccharides, (flours, gums, and extracts from vegetable products) have been tested. While alghae euchemae have proved to be the most effective additive, corn and 00 flours are the least effective. Attempts to explain their differences have been made considering their chemical interactions with the polar molecules of asphaltenes within the complex framework of their supramolecular hierarchical structures. Through Arrhenius analysis, a correlation between activation energy and preexponential factor has been found, which can be useful for practical purposes, together with an unexpected consistency with the behavior of simple liquids, despite the striking differences in structure. Furthermore, a qualitative model has been suggested. The added value of this work is the focus on polysaccharides constituting low-cost, high availability materials which are sometimes even found as waste in industrial processes, all factors which, together with the environmental issues connected with their use, can be considered for large-scale applications.

The dynamic features of bis(2-ethylhexyl)phosphoric acid (HDEHP)/n-octylamine (NOA) mixtures have been investigated as a function of the NOA mole fraction and temperature by (1)H NMR spectroscopy and rheometry. All data consistently suggest a composition-induced glass-forming behavior. The microscopic factors responsible for this behavior have been highlighted and have been explained in terms of driving forces given by HDEHP-to-NOA proton transfer, the tendency of the resulting species to establish H bonds and to spatially segregate the alkyl chains. The study sheds light on the molecular mechanism responsible for the peculiar behavior of transport properties in such systems and furnishes basic knowledge to be used to design novel materials with planned physicochemical properties.

The rheological effects of polyphosphoric acid (PPA) on bituminous binders with similar mechanical and chemical–physical properties, but with different chemical compositions, have been investigated. The effects of polyphosphoric acid were studied through traditional bituminous-binder-type characterization tests and via rheological investigations by dynamic and steady shear rheometry. It was observed that PPA, probably reducing the asphalten aggregate size, extends the range of viscoelastic behavior, moving the transition to a viscous liquid towards higher temperature and, therefore, improving the mechanical behavior for high temperature applications. These effects seem more evident at low PPA concentrations and suggest the potential existence of saturation effects.

The mechanical properties of bitumen are the result of the chemical composition and arrangement of the molecular structures (phases present). The loss of elasticity of the bitumen with aging is mai...

In the present work a laboratory evaluation of the low-temperature rheological properties of neat and polyphosphoric acid (PPA) modified bitumens by using a Dynamic Mechanical Analyzer (DMA) is presented. Fundamental rheological properties were evaluated in controlled kinematic conditions and the results obtained were compared with traditional procedures such as the Fraass breaking point. The results show that the effect of polyphosphoric acid addition at low temperature is strongly dependent on bitumen composition (i.e. wax and asphaltene content), nevertheless it seems that PPA is able to decrease the glass transition temperature (Tg) and to increase the stiffness, improving the low temperature performance of the modified materials.

Bitumens are currently modelled as a colloidal system and are the most used materials for road paving. Despite this large application, asphalts are still affected by some inconveniences that bring to road deterioration. This is prevalently due to temperature cycling which is related to the given local climate conditions and to the incident traffic load. In the last decades bitumen performances have been improved by means of different types of additives in order to match various expectations. This improvement is often the result of the indications given by traditional empirical standardized tests like penetration grade, temperature ductility and Fraas breaking point. The comprehension of the chemical mechanism that regulates the action of the used additives can greatly help in designing new and better performance materials. By means of a Stress Controlled Rheometer we present a laboratory evaluation of the rheological properties of a 70/100 bitumen which has been doped by different percentage of Polyphosph...

The role of nonionic vesicles on the rheological behavior of Pluronic F127 is investigated above the dilute regime and below the cloud point of the nonionic surfactant. F127 is a copolymer possessing sol-gel transition by heating attributed to a phase transition from micellar to cubic. The presence of surfactant vesicles is expected to enhance the compartmentalization of a variety of drugs, independently of their affinity to the solvent. Such entrapment would be suitable for controlled release of the drugs in different applications. We address here a mixed Pluronic-nonionic surfactant system with particular emphasis to the effects of the surfactant on the rheological properties of the Pluronics, and the correlation between these properties and drug release control. The results show that the rheological properties of the mixed system are mainly governed by the behavior of the polymer alone and that the mixed system can be useful to control the percutaneous permeation of a small drug, such as Diclofenac Sodium salt.

The temperature dependent rheological and structural behavior of a long-chain C(16)E(4) (tetraethylene glycol monohexadecyl ether) surfactant in D(2)O has been studied within the regime of low shear range. In the absence of shear flow, the system forms a lamellar liquid crystalline phase at relatively high temperatures. The present paper reports on the shear-induced multi-lamellar vesicle (MLV) formation in C(16)E(4)/D(2)O at 40 wt.% of surfactant in the temperature range of 40-55 °C. The transition from planar lamellar structure to multi-lamellar vesicles has been investigated by time-resolved experiments combining rheology and nuclear magnetic resonance (rheo-NMR), rheo small-angle neutron scattering (rheo-SANS) and rheometry. The typical transient viscosity behavior of MLV formation has been discovered at low shear rate value of 0.5s(-1).

At high temperatures, pentaethylene glycol monododecyl ether (C12E5) in D2O forms a swollen lamellar phase. This letter reports the shear-induced multilamellar vesicle (MLV) formation in a sample that contains 40 wt % C12E5 dissolved in D2O at 55 °C. This transition has been investigated by time-resolved rheo-nuclear magnetic resonance, rheo small-angle neutron scattering, and rheometry. The typical transient viscosity behavior of MLV formation has been discovered at 1 s(-1). For the first time, it has been found that MLVs are not stable over time when subjected to high shear rates. Our results show that the MLV stability is confined in a narrow region in the range 1-10 s(-1) shear rates. This is not observed for other CnEm surfactants.

Rheology and rheo-(2)H NMR measurements are presented for 30 wt % ammonium perfluorononanoate (APFN)/(2)H(2)O mixture in the temperature range 20-70 °C. A first-order lamellar-to-nematic transition occurs at 42 °C, and a first-order nematic-to-isotropic transition occurs at 49 °C. Different rheological behaviors of the lamellar phase were observed with increasing the temperature. The lamellar structure at low temperature (Lα(-)) has a clear gel-like viscoelasticity, while at high temperature the lamellar structure (Lα(+)) has a liquid-like response. In this study we have observed for the first time, along with the lamellar phase of a surfactant containing fluorinated fatty acid, the formation of multilamellar vesicles (MLVs) ("onions") induced by shear. With the aid of nonlinear rheology and rheo-NMR techniques, onion formation was found to occur in both temperature regimes of the lamellar phase, but at different strain units. It is suggested that the lamellar phase consists of smectic structures in both Lα(-) and Lα(+), but with different percentages of defect density.

This work proposes an effective algorithm for description of nonlinear deformation of hereditary materials based on Rabotnov’s method of isochronous creep curves. The notions have been introduced for experimental and model rheological parameters and similarity coefficients of isochronous curves. It has been shown how using them, one can find instantaneous strains at various stress levels for description of nonlinear deformation of hereditary materials at creep. Relevant equations have been determined from the nonlinear integral equation of Yu. N. Rabotnov for the application cases of Rabotnov’s fractional exponential kernel and Abel’s kernel for nonlinear deformation of hereditary materials at creep. The improved methods have been given for determination of creep parameters α, ε0, δ, β, and λ. By processing and using test results for material Nylon 6 and glass-reinforced plastic TC 8/3-250, the process has been shown for sequential implementation of the developed methods for description of linear and nonlinear deformation of these materials at creep. From the results of the experimental investigation performed by the authors of this paper, it has been determined that fine-grained, dense asphalt concrete at the temperature of 20 ± 2 °C and stresses up to 0.183 MPa at direct tension is deformed considerably in a nonlinear way. It has been shown in an illustrative way by construction of isochronous creep curves at various load durations and curves of experimental rheological parameter at various stresses. Nonlinear deformation of asphalt concrete at creep is adequately described by the proposed methods.

Droplet size distribution strongly affects macroscopic properties of emulsions. In this work rheological and NMR (nuclear magnetic resonance) analyses were performed to evaluate material properties as well as droplet size distribution and possible flow-induced alteration. The investigated materials were commercial dairy emulsions, based on milk, vegetable fats, a mixture of sugars, emulsifiers (hydrophilic or lipophilic) and natural stabilizers (carrageenan and guar gum). Rheological properties of three different dairy emulsions were related to the droplet size distribution obtained by NMR and dynamic light scattering (DLS) techniques. NMR seems to be a particularly useful technique because no previous sample treatment is necessary, whereas DLS requires a significant emulsion dilution that could change the droplet size distribution. Obtained results evidence the effect of two relevant ingredients (surfactants and fats) on rheological properties and droplet size distribution of tested emulsions. For sample containing sunflower oil and a hydrophilic emulsifier, rheo-NMR evidenced mechanical instabilities also confirmed by rheological tests. Comparison of results about the droplet size distribution evaluated by NMR and DLS evidenced that in this case sample dilution could affect size distribution. Finally, rheo-NMR was confirmed to be a powerful instrument capable of determining the material structure and alterations induced by the flow.

In order to obtain new functional soft systems for use as templating agents for the construction of functional mesostructured materials, the dynamic ordered soft systems formed by a hydrophilic ionic iridium(III) complex (IrPa) embedded into two different concentration F127–water mixtures have been investigated. To this aim, combined spectral and time-resolved photophysical techniques and rheological methods have been employed. The position of the chromophore inside the micellar, cubic and hexagonal phases of the F127 polymeric neutral surfactant in water was effectively determined. The hydrophilic character of the iridium(III) complex chosen allowed preferential functionalization of the F127 corona in the micellar and cubic phases.

Usually in nonionic surfactant aqueous systems of the CnEm type, a lamellar phase occurs over a wide temperature and concentration range. For some CnEm surfactants, multi-lamellar vesicle (MLV) formation has been observed when the lamellar phase is subjected to shear flow. This communication reports the shear flow behavior at different shear rate values of a CnEm (where "n" is 12 and "m" is 3) aqueous system at 34 degrees C. The typical transient viscosity behavior of the shear-induced MLV formation in C12E3/D2O at 50 wt% of surfactant has been observed. The MLV formation is confirmed by time-resolved rheo-small angle light scattering (SALS) experiments. The experimental data show an intermediate structure that has been attributed to a multi-lamellar cylinders (MLCs). (C) 2011 Elsevier Inc. All rights reserved. (Less)

Vesicles composed of sodium oleate (NaO) and monoolein (MO) are adequate candidates for drug nanoencapsulation and controlled release due to their stability and perceived biocompatibility. The object of the present study is to design hydrogels based on those anionic vesicles and polymers of both non-associative and associative type. The selected macromolecules were k-carrageenan (KC), carboxymethyl cellulose (CMC) and hydrophobically modified carboxymethyl cellulose (HMCMC). While the polymer-vesicle association was probed by rheology, the influence of the polymer on the vesicle stability was monitored by cryo-TEM and calorimetric measurements. The effects of the polymer on the rheological properties of surfactant aggregate solutions clearly depend on the polymer type: the storage moduli of the polymer-vesicle mixtures, compared to the vesicles alone, increases around 2 orders of magnitude if the polymer is non-associative and 4 orders of magnitude if the macromolecule is of associative type. As the vesicles are added, the non-associative polymer networks tend to be disrupted, while the networks formed by associative polymer get more robust. These observations can be explained by fundamental changes in electrostatic/hydrophobic interactions: vesicles entrapped in KC networks convert the polysaccharide in a highly charged entity and favor high electrostatic repulsions between the chains; this encourages network collapse. The opposite picture is experienced in HMCMC systems, i.e., such network is stabilized by the presence of vesicles. This is ascribed to the enhanced hydrophobic association, compensating the electrostatic repulsions between vesicles and polymer chains.

Pavement materials play an important role in overall pavement sustainability including material acquisition processing, and transportation. The main objective of the present study is to evaluate the effectiveness of new additives, to reduce bitumen’s fume emission expelled into the atmosphere, during the processing of asphalt concrete. The new additives act by trapping bitumen’s volatile substances avoiding their release at high temperatures. In this paper, we have been tested the performance of 2 types of mesoporous silica-based additives (AntiSmog 1 and AntiSmog 2). The idea of using these additives to reduce the emission of fumes in bitumen has been submitted as a patent. To quantify and characterize the emitted fumes, thermogravimetry (TGA) and gas chromatography-mass spectrometry (GC-MS) technique have been used. Dynamic Shear Rheology (DSR) has been used to check the rheological properties and the possible sedimentation issues that could occur after the addition of the additives

Environmental protection is also pursued by promoting the saving of oil reserves and the proper management of waste through a circular economy. Following this objective, the present study encourages the use of recycled and by-product materials for the production of bituminous binders. The powdered rubber (R) from end-of-life tyres and the re-refined engine oil bottom (REOB), i.e. the by-product of refining mineral waste oils, were used to replace a certain amount of standard bitumen. The experimental program aims to characterize the interaction between R and REOB in order to use them as virgin bitumen extenders. The multiple variables of the production process that may affect the R-REOB blends and in turn the binders’ final properties were evaluated. The R-REOB mixes were prepared by varying the type of REOB, the R content and the mixing temperature. The rheological analysis was performed by means of dynamic shear rheometer (DSR) tests with the aim to define the variables that strongly influence the response of the R-REOB compound. As a result of this preliminary study, the second phase will focus on extended bitumens that will be prepared considering some of the studied extenders.