Bituminous Materials Research Articles

Quantum Chemical Modeling of the Effects of Hydrated Lime (Calcium Hydroxide) as a Filler in Bituminous Materials

Hydrated lime is widely used as a mineral filler to improve several properties of bituminous materials such as reducing the susceptibility of the composite to moisture-induced damage. Although experimental evidence supports the efficacy of using hydrated lime as a mineral filler, the molecular scale mechanism of reactivity of hydrated lime within the bitumen to reduce moisture damage is not understood. This is important when considering the durability of structural applications of bituminous materials such as asphalt concrete pavements subjected to both environmental and loading extremes. In this study, the interaction between hydrated lime and the key molecular building blocks of bitumen is modeled using density functional theory and compared against analogues of other common fillers such as calcite and quartz. Free energies of dissociation (ΔGdissoc) are calculated, and the nature of the bonds is characterized with contour maps of the Laplacian of the electron density. Hydrated lime is capable of reacting with specific functional groups in bitumen moieties and developing strong, water-resistant complexes. Among the functional groups investigated, carboxylic acids are the preferential reaction sites between hydrated lime and the bitumen moieties. Values as high as ΔGdissoc = +49.42 kcal/mol are reported for hydrated lime with water as the surrounding solvent. In contrast, analogues of calcite (ΔGdissoc = +15.84 kcal/mol) and quartz (ΔGdissoc = +4.76 kcal/mol) are unable to chemically react as strongly as hydrated lime in the presence of water. Contour maps of the Laplacian of the electron density indicate that the bonds between hydrated lime and model asphalt moieties are of an ionic nature. The atomistic modeling results correlate with thermodynamic calculations derived from experimental constants and are consistent with infrared spectrometric data.

Experimental Characterization of Viscoelastic Behaviors of Nano-TiO2/CaCO3 Modified Asphalt and Asphalt Mixture.

The purpose of this paper is to promote the application of nano-TiO2/CaCO3 in bituminous materials and present an experimental characterization of viscoelastic behaviors of bitumen and bituminous mixture modified by nano-TiO2/CaCO3. In this work, a series of viscoelastic behavior characterization tests were conducted, including dynamic shear rheometer (DSR) test for bitumen, uniaxial static compression creep test and dynamic modulus test for bituminous mixture. Moreover, various viscoelastic models with clear physical meanings were used to evaluate the influence of nano-TiO2/CaCO3 on the macroscopic performance of bitumen and bituminous mixture. The results show that bitumen and its mixtures are time-temperature dependent. The Christensen-Anderson-Marasteanu (CAM) model of frequency sweep based on DSR test indicated that adding nano-TiO2/CaCO3 can effectively capture the sensitivity of temperature. In addition, the incorporation of nano-TiO2/CaCO3 in bituminous mixture can significantly enhance the high-temperature anti-rutting, and slightly improve the low-temperature anti-cracking as well. At the same time, the modified Burgers model can accurately describe the viscoelastic behavior of bituminous mixtures in the first two creep stages, reflecting the consolidation effect of bituminous mixture. Also, the generalized Sigmoidal model can accurately grasp the characteristics of the relationship between dynamic modulus and reduced frequency and achieve good prediction effects in a wider frequency range.

Study on the conservation of bituminous mixes in high mountain roads and coastal zones

The road conservation activities allow to maintain the characteristics of the platform elements to ensure that vehicle mobility is carried out comfortably and safely. The orographic conditions of Spain, with a large length of high mountain roads and others at sea level; and winter weather events, with low temperatures, thermal gradients, wind, water, ice, snow… which cause deposits of particles, filler, soils, small metals, or sea salt on the pavement surface, can be dangerous in the circulation of vehicles. One of the traditional methods for maintaining wheel-pavement adhesion is to apply flux products, mainly salt (sodium chloride, NaCl) and calcium chloride (Cl2Ca), solidly or humidified (salt brine). These chemical fluxes have the property of preventing the formation of ice as antifreeze, or facilitating their melting if it has already formed. This research studies the influence of salt on the surface of a bituminous pavement. The interaction of salt and bituminous layer materials has been analyzed in different ways: first, the bituminous mixture is immersed in salt water; second, salt is another aggregate of the bituminous mixture; and finally, the hot mix asphalt is made with aggregate impregnated with salt in its surface. The properties of the mixtures have been analyzed in the laboratory: density, air voids, adhesion, indirect tensile strength and plastic deformation. To do this, Marshall test, Indirect Tensile Strength Ratio (ITSR), and rutting test have been performed. The properties of hot mix asphalt do not decrease significantly when it is manufactured of salt added as aggregate. It also offers good results when the specimens are inside recipients with salt water. The bituminous mixture offers negative results when it is manufactured with natural aggregate submerged in water with salt previously, because the adhesion between the materials is low.

The Master‐Curve Band considering Measurement and Modeling Uncertainty for Bituminous Materials

This paper proposes using the master‐curve band (MCB) to incorporate the unavoidable measurement errors and modeling uncertainty into the bitumen master‐curve construction. In general, the rheological property of bitumen within the linear viscoelastic region is characterized by the master curve of modulus and/or phase angle, provided that the bitumen complies with the time‐temperature superposition principle (TTSP). However, the master‐curve construction is essentially a mathematical fitting process regardless of whether or not the original data is perfect enough to fit. For this reason, the MCB was introduced to consider the uncertainty information instead of a single master curve. Rheological data of four kinds of bitumen including unaged and aged bitumen were used to construct the MCBs. The results indicated that the generalized sigmoidal model showed the widest master‐curve band, followed by Christensen‐Anderson‐Marasteanu (CAM) and CAM (Gg) models. The width of MCB was a useful tool to identify the sensitivity of bitumen to rheological models. The sensitivity of bitumen to rheological models is associated with the number of active parameters in rheological models and model parameters’ confidence intervals. The construction of an MCB was beneficial to select the rheological models. Accordingly, the CAM (Gg) model is proved to be the best to analyze the aging effects.

Effect of the bitumen type on the temperature resistance of hot mix asphalt

Bitumen is a material that binds the aggregates of roadways to allow vehicles to travel in the best conditions of safety and comfort. The bitumen types currently used in pavements in Morocco are pure bitumen (PB) of 20/30 and 35/50 classes and polymer-modified bitumen (PMB). Given the large variety of bitumen types, it is important to study the effect of bitumen type on the thermal resistance of asphalt mixes. The purpose of this study is to examine the inherent characteristics of different types of bitumen and to suggest the one that best adapts to Moroccan meteorological conditions. Bitumen identification, including penetrability at 25 °C, softening temperature, and Dynamic Shear Rheometer (DSR) tests were carried out in order to study the adaptation of these materials to local temperatures. Rutting tests were also executed on the asphalt mixture. Test results have shown that modified bitumen allows improving the resistance of bituminous materials against high temperatures and preventing the rutting phenomenon.

Mineralogical and Geochemical Properties of Clays to Associated with the Yarıkkaya (Yalvaç-Isparta) Coal Deposits

This study contains the mineralogical and geochemical characteristics of clays associated with Yarıkkaya (Yalvaç-Isparta) lignite coals. The clays are located in three lignite coal sites in the Yarıkkaya Neogene basin. The claystone member mainly consisting of claystone, carbonated shale, marl and locally mudstone, is settled in the Miocene Yarıkkaya formation. The clay occurrence is generally at the bottom of coal and sometimes at the upper parts of coal levels or laterally transitive with clays. The clay deposits have gray, dark gray and khaki colour, and they are generally covered by brown or gray bituminous materials. Their thickness changes between 5-15 m, and has a maximum thickness of 40 m as intercalated with the other lithologies in the Yarikkaya-3 location. The mineral paragenesis of clay formation mainly consists of illite, kaolinite, chlorite, and to a lesser amount smectite. SiO2/Al2O3 vs. Fe2O3/K2O ratios indicated that Yarıkkaya clay samples are defined as mainly shale, less greywacke and quartz arenite. The average Al2O3/TiO2 ratios suggest that Yarıkkaya clay samples show intermediate source rock. Cu, Ba, Pb, Zn, Co, Zr, Ga, Rb, V are considerably lower, only Ni contents are higher contents of with respect to PAAS. Geochemical contents of the investigated clays show that the clastics which are derived from the Seydişehir formation rocks could give a material to the Yarıkkaya lacustrine sediments.

Fatigue Resistance of Bituminous Mixtures and Mortars Containing High Reclaimed Asphalt Content.

With the increased use of reclaimed asphalt (RA), the ability of bituminous materials to resist fatigue cracking may face a decline mainly due to the aged reclaimed asphalt binder (RAB), especially when RA is used at higher rates and not sufficiently treated. In this study, the bulk scale (asphalt) and its subscale (mortar) were employed to evaluate the effect on fatigue resistance when a RAB is added, by considering three replacement rates: 0%, 40%, and 70% RAB. The fatigue testing of asphalt mixtures was carried out using a four-point bending (4PB) setup, while the mortars were tested using a new column-like geometry utilising a dynamic shear rheometer (DSR). The fatigue properties were further analysed using dissipated energy concepts. The aim of this study was, first, to assess whether the inclusion of a RAB can provide at least similar fatigue properties compared to an all-virgin mix, and second, to evaluate whether the proposed treatment is beneficial for the mixtures with a RAB. The asphalt tests revealed that the inclusion of a 40% RAB led to increased fatigue resistance, whereas the mortar tests showed that the inclusion of RAB has an inverse effect on fatigue life.

Molecular simulation and experimental studies on CO2 and N2 adsorption to bituminous coal.

A coal fire is one of the most serious disasters in coal mining. To improve the efficiency of an inert gas for extinguishing the fire, the adsorption behavior of coal in CO2/N2 mixed gas was investigated in this study. Proximate analysis, ultimate analysis, solid-state 13C nuclear magnetic resonance spectroscopy (NMR), X-ray photoelectron spectroscopy (XPS), and molecular dynamics (MD) were applied to analyze and establish the bituminous coal molecular model. The adsorption behavior of bituminous coal in mixed gas mixtures with different proportions was studied using the bituminous coal model and Materials Studio (MS) software. A self-built coal adsorption experimental system was used for experiments. The adsorption of bituminous coal to CO2 is stronger than that to N2, and there is a competitive adsorption relationship between them. The amount of CO2 adsorbed by the coal gradually increases as the CO2 partial pressure rises, consistent with the Langmuir model. With an increase in CO2 pressure, the total adsorption capacity, which is divided into the rapid increase stage, slow growth stage, and stable stage, also increases. The coal adsorbs 0.5050 cm3/g, 0.7455 cm3/g, 0.9450 cm3/g, 1.0715 cm3/g, and 1.2000 cm3/g for pure N2, 2%, 5%, 7%, and 10% CO2, respectively, in the experiment. The results of the simulation and experiment show the same trend, which means that the injection of a small amount of CO2 into pure N2 will greatly improve the gas adsorption volume of the coal, demonstrating that it is feasible to improve the ability of the coal to absorb mixed gases by changing the gas concentration and consequently to increase the efficiency of inert gas for fire extinguishing and suppression.

Towards an enhanced fatigue evaluation of bituminous mortars

The fatigue resistance, as a performance indicator, is of paramount importance for the selection and benchmarking of bituminous materials. The bituminous mortar can be considered as the medium that connects and envelopes the coarse aggregate skeleton, and hence will significantly influence the fatigue resistance at bulk-scale. Therefore this study presents the steps and challenges of a new testing framework to evaluate the fatigue resistance of bituminous mortars. To do so, first, a new test geometry is introduced, which will ensure cohesive failure in a predefined area. The integrity of this sample geometry is assessed theoretically through finite element simulations and by computer tomography scans. Secondly, specimens of the new geometry are evaluated experimentally using a dynamic shear rheometer, where time-sweep tests are performed on two control mortar types under various test conditions. The control mortar types are fabricated using two commercial bituminous binders, one modified and one neat binder, to evaluate the effect of binder type. The test results are comprehensively analysed using fundamental dissipated energy-based concepts but also empirical and phenomenological failure criteria, providing insights into the failure evolution. For the tested mortar types, the analysis shows good convergence with the considered fatigue models. Finally, using dissipated energy concepts led to the most consisted fatigue model, which is independent of binder type and test conditions.

Chemical and Performance Characteristics of Rejuvenated Bituminous Materials with High Reclaimed Asphalt Content

AbstractThe present paper aimed at studying the effectiveness of waste vegetable oil (WVO) as rejuvenator in restoring the desired properties of recycled asphalt mixes. The effectiveness of rejuven...

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.

Evaluation of the adhesion characteristics of material composition for polyphosphoric acid and SBS modified bitumen based on surface free energy theory

Styrene-butadiene-styrene (SBS) modified bitumen is widely applied to the construction of high-grade pavement because of its good pavement properties. However, with the rising price of SBS polymer, SBS modified bitumen is more expensive. By adding the cheap modifier polyphosphoric acid (PPA) to bitumen and compounding with SBS, the production price of SBS modified bitumen is obviously reduced, and the miscibility between SBS and bitumen is promoted. In this study, the effect of base bitumen type, PPA type and raw materials content on the adhesion performance of polyphosphoric acid compounded SBS (PPA/SBS) modified bitumen was evaluated quantitatively using the contact angle test and surface free energy method. Three different bituminous materials, two types of PPA, SBS, stabilizer, compatibilizer and dibutyl phthalate (DBP) were used as raw materials to prepare PPA/SBS modified bitumen. The results indicate that PPA improves the adhesion of PPA/SBS modified bitumen, but with an increase in PPA content above a certain value, the cohesion work, adhesion work and compatibility ratio of PPA/SBS modified bitumen decrease gradually and the peeling work increases gradually. In the blending process of PPA and SBS, changes in adhesion performance depend mainly on the base bitumen type, PPA type and raw material content. Using SK 90# base bitumen; 105% PPA; and PPA, DBP, extraction oil, and SBS contents of 0.5%, 1%, 1.5%, and 3.5%, respectively, the water damage resistance of PPA/SBS modified bitumen is considerably improved.

Flame retarding and smoke suppressing mechanisms of nano composite flame retardants on bitumen and bituminous mixture

To understand flame retarding and smoke suppressing mechanisms of developed nanocomposite flame retardant (NCFR) on bitumen and bituminous mixture, thermogravimetry (TG) and cone calorimeter (CONE) tests were performed, and combustion parameters of TG and CONE tests were discussed. Results indicate that combustion behaviors of bitumen and bituminous mixture are efficiently inhibited by NCFR. More compact and stable char residue is formed on bituminous mixture. NCFR reduces the smoke release amount and mass loss rate in condensed and gas phases during bituminous mixture combustion, and plays the roles of flame retarding and smoke suppressing effects, improving fire safety of bituminous materials.

Alteration of initial and residual healing potential of asphalt binders due to aging, rejuvenation, and polymer modification

Asphalt binders are known to exhibit an inherent ability to repair damage. Such self-healing potentially affects the fatigue damage performance of bituminous materials. There are contradicting findings about the effects of aging and polymer modification on healing. The effectiveness of rejuvenating agents also has not been sufficiently addressed. In the present study, three healing indices have been defined to provide a more complete representation with which to quantify the healing potential of binders. These indices have been defined using damage characteristic curves derived from interrupted linear amplitude sweep tests. Initial healing (IH) describes the immediate reduction in the damage accumulated after the rest period. Residual healing (RH) shows the lasting effect of healing and total healing (TH) is a combination of IH and RH. The results demonstrate that IH does not present a complete picture of healing, particularly at low and intermediate levels of damage. While, RH better exhibits the detrimental effect of aging, the healing ability of SBS (styrene–butadiene–styrene) binder at higher damage levels, and the positive effect of the use of the rejuvenating agent. The healing model shows that, irrespective of the healing index and binder, the effect of loading interruptions at higher levels of damage, along with increased stiffness because of aging, prevail over the positive effects of an increase in the duration of the rest period.

Inherently Functionalized Carbon from Lipid and Protein-Rich Biomass to Reduce Ultraviolet-Induced Damages in Bituminous Materials.

This paper examines the merits of using an inherently functionalized carbon, referred to as biochar as a free radical scavenger. The biochar was made from thermochemical liquefaction of a blend of algae (rich in protein and nucleic acids) and manure (rich in lipid). Here, we studied biochar’s efficacy as a free-radical scavenger and ultraviolet blocker to qualify it as an anti-aging additive in construction, including roofing shingles made from the bituminous composite. The study’s results show that the addition of biochar to bitumen significantly reduced the aging of bitumen. All tested biochars made from various relative proportions of algae and swine manure were found to be effective at reducing the extent of aging; however, the biochar made from algae alone was the most effective. The algal biochar was found to be an effective antiaging additive delaying aging up to 36%, as evidenced by lower rheology and the chemistry-based aging index compared to those of control bitumen after being exposed to the same aging protocol. Algal biochar was found to be more effective than other studied biochar scenarios owing to its inherently functionalized nature. The latter result could be attributed to the high surface area and rich phenol functional groups in algal biochar, turning it into an effective free-radical scavenger. The study outcome highlights the applicability of this inherently functionalized carbon referred to as biochar in construction to enhance sustainability while promoting the circular economy and the biomass value chain.

Towards the Valorization of Phosphate Wastes in bituminous materials

The phosphate production process generates millions of tons of wastes annually in Morocco. These mine tailings could have negative impacts that can be observed on the surrounding environment. Therefore, innovative strategies should be proposed to valorize the solid wastes. This paper investigates a new approach of phosphate waste valorization in producing asphalt mixtures which can be a cost-effective and eco-friendly solution for managing these wastes. The main goal of the presented study is to examine the feasibility of using three phosphate wastes for fabrication of bituminous materials and to discover the better waste to be added in asphalt mixtures. Many solid wastes are selected to be used as minerals fillers. it is showed that the viscous flow behavior of the asphalt binder containing phosphogypsum and fly ash wastes is substantially improved in compression of that of asphalt binder with phosphate sludge filler. In addition, it was observed that phosphogypsum waste can enhance the mechanical properties of asphalt binder as well as its performance against rutting in comparison to the others wastes.

A study of essential components of three types of Bituminous Materials in Mishraq sulfur Mine

.The chemical constituentis of three types of bituminous materials found in different conditions in Mishraq sulfur Mine was studied. The FTIR spectroscopy showed reduce in the length of hydrocarbon‏ chains from the intensity of paraffinic bands in bitumenous materials of Frasch sulfur Mine (BM) compare with natural bituminous materials (NB) and Bituminous materials which extracted in-depth about 200 m without exposing to Frasch process condition (BB). The percentage of asphaltene in (MB) which increases dramatically is found 63.64% compared with (BB) and (NB) which 37.37% and 14.28% respectively and a similar decrease in percentage petrolene (maltene) . A percentage of n-hexane fraction by silica gel chromatography of petrolene (MB) is 18.49% compared with (BB and N.B) are 25.06 % and 47.05 % respectively while the cyclohexane fractions of petrolene MB are four-time of N.B and three-time of B.B . From all results, we conclude that a reaction has occurred between sulfur and bitumenous materials especially hydrocarbon chains of Aromatics and naphthenic rings in sulfur well during Frasch process which leads to an increase in asphaltene percentage and decrease of petrolene.

Application of nanotechnology in pavement engineering: a review

Nanotechnology utilizes the research and technology established at the nuclear and molecular or macromolecular levels to comprehend the nanoscale phenomena. In road construction, the bituminous materials are used in enormous amounts. The macroscopic mechanical conduct of these materials still largely relies on microstructure and physical characteristics at a micro and nano scale level. For many years, scientists and engineers have been exploring nanotechnology in civil engineering, but nanotechnology use in this sector has been limited. Nanotechnology has caught the interest of experts and has progressively penetrated into the field of pavement engineering. The article reviews the published works carried out to study the use of nanomaterials in asphalt pavements and illustrates the technique used to enhance asphalt features by the use of these nanomaterials. In this review, multiple nanomaterials are discussed followed by characterization of these nanomaterials, preparation techniques of modified asphalt binder, and finally the effect of nanomaterials on the efficiency of base asphalt binder as well as the asphalt mixture. The primary focus continues on the use of nanotechnology in pavement engineering to achieve a better atmosphere for society based on recognized pavement engineering requirements and difficulties.

Rainwater storage in urban environments using green roofs

This article discusses the use of green roofs as rainfall water storage in its soil matrix. The methodology is analytical based on mathematical models, where runoff produced in an urban area is compared with current conditions of ordinary roofs with ceramic or bituminous materials as the original scenario, against another where green roofs are used. The study area is located in the Palavecino municipality of Lara state in Venezuela, in the flood zone of Quebrada Tabure. In this research, a quantitative comparison of the direct runoff hydrographs of the proposed scenarios was used, obtaining as a main result the reduction of runoff between 60% and 80% according to the period of return. An interesting point of this research was the incorporation of the routing of hydrographs on the roofs, reducing even more the peak flow over 90%, and delaying the peak time of the generated hydrographs between 10 and 12 minutes while the total duration of the hydrographs increase more than three times.

Inhibitory effects of developed composite flame retardant on bituminous combustion and volatile emissions

Bituminous materials release plenty of heat and hazardous volatiles when exposed to high temperature. To develop a sustainable and efficient composite flame retardant (CFR) of bituminous materials, new compositional formulation proportions of selected Ca–Al hydrotalcite (CAHC), ammonium polyphosphate (APP), coated red phosphorus (CRP) and expanded vermiculite (EV) in the prepared CFR were confirmed. Then the inhibitory effects of CFR on non-isothermal combustion kinetics characteristics of bitumen and the dynamic release processes of various volatile constituents were discussed using thermogravimetry/differential scanning calorimeter-mass spectrometer-Fourier transform infrared spectroscopy (TG/DSC- MS-FTIR) combined approach. Test results suggest that the combustion processes of bitumen and CFR bitumen mainly include obvious multistage exothermic reactions. When the heating rate is elevated, the incomplete combustion of bitumen and CFR bitumen is increased, and more heat and volatiles are emitted. Further, as the bituminous temperature is gradually raised, the CAHC, APP, CRP and EV in added CFR are decomposed in turn to inhibit the multistage combustion process of bitumen, showing comprehensive and synergistic flame retarding effects due to dilution, cooling, and insulation. Therefore, the combustion of bituminous four components is correspondingly inhibited by the matched flame retardant in CFR so that the bituminous thermal stability is obviously improved by added CFR. Additionally, the CFR produces thicker intumescent layer on bitumen, which insulates bitumen with oxygen, and decreases the volatile release and molten droplet formation. Fewer macromolecular volatiles are emitted from CFR bitumen than those from bitumen. Moreover, the dynamic release process of various volatile constituents during the bituminous combustion is efficiently suppressed by CFR. The developed CFR plays an important role of flame retarding and smoke suppressing functions, providing an efficient and green flame retardant for bituminous materials when exposed to a fire.