Action of micro-organisms on bituminous materials. II. Composition of low molecular weight asphaltic fractions determined by microbial action and infra-red analyses

Assay of narrow fractions from three asphalts designated 1A, 3A, and 6A indicates the chemical nature of some of the asphaltic constituents utilised by Mycobacterium ranae and Pseudomonas 196Aa. These organisms were tested with pure hydrocarbons for growth response. The results indicated that Ps. 196A utilised n-alkanes containing 6—22 carbon atoms, some alkenes and fatty acids but none of the aromatic hydrocarbons tested. M. ranae utilised substituted benzene compounds, but not benzene, alkenes or most alkanes. Using asphalt fractions obtained by thermal diffusion, infra-red data were correlated with microbial results. The two approaches support each other in partial elucidation of the structures of the asphalt fractions.     

原油中沥青质的危害与预防

由于原油组成以及所处环境条件的改变等原因,沥青质在原油的开采、储运、后处理过程中容易发生沉淀现象;在沥青产品的使用过程中,由于沥青质的老化也会给带来很大的影响。本文从油藏、采油、储运、炼化、沥青产品的使用等方面分析了胶质沥青质所带来的影响,结合前人的实验分析,针对胶质沥青质的危害,提出了改善胶质沥青质影响的方法和措施。     

Viscous,damping, and mechanical properties of epoxy asphalt adhesives containing different penetration-grade asphalts

Epoxy asphalt adhesive (EAA) is a thermosetting polymer modified asphalt that has been widely applied on steel bridge decks as a strong adhesive and waterproof layers. In this study, the influence of the asphalt penetration grade on the viscosity, damping and mechanical properties, bond strength, and microstructures of EAAs was investigated. The viscosity of the EAAs increased with increasing asphalt penetration grade. The presence of base asphalt increased the glass-transition temperature (T _g) of the neat epoxy. The asphalt penetration grade had a negligible effect on the T _g values of the EAAs. The existence of base asphalt improved the damping behaviors of the neat epoxy. Moreover, the damping properties of the EAAs increased with increasing asphalt penetration grade. The tensile strength, elongation at break, and bond strength values of the EAAs increased with increasing asphalt penetration grade. The bond strengths of the EAAs were 7- to 10-fold higher than that of the neat asphalt. The asphalt penetration grade had a negligible effect on the bond strengths of the EAAs. Morphological observations revealed that the average size of the dispersed asphalt particles in the epoxy decreased with increasing asphalt penetration grade. A more homogeneous phase separation was formed in the EAA with a higher penetration-grade asphalt. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47027.     

A new test method to assess the bacterial deterioration of cementitious materials

The biodegradation of cement-based matrices by agro-industrial effluents is a very complex phenomenon. In this work, a test was developed – the Build-Mat Bio-test (BMB test) – to examine the degradation mechanisms caused by microbial activity on any type of building material. The main objective of this device was to analyze and distinguish between the effects caused by the bacteria and those caused by their metabolites in the deterioration. In this study, the BMB test was used to evaluate the impact on cementitious matrices of the bacterium Escherichia coli, found in liquid manure. The mechanisms and kinetics of deterioration resulting from exposure to the bacterial culture or to the metabolites were compared with those obtained with synthetic organic acids alone. It was notably observed that the bacterial suspension caused more intense deterioration and higher alteration kinetics as compared to the medium without microorganisms and to the synthetic acid solution.     

Utilization of sulfur and crumb rubber in asphalt modification

In this study, waste crumb rubber and sulfur were utilized to enhance the performance of asphalt binder for pavement applications. About 20–50% of sulfur and 1–6% crumb rubber were used. Melt properties were investigated using thermal analysis, dynamic and steady shear rheology, and artificial aging. Rheological tests were carried out in ARES rheometer. Both steady and dynamic shear rheology showed that crumb rubber improved the viscoelastic properties of the sulfur‐extended asphalt binder. Crumb rubber modification reduced temperature susceptibility of sulfur/asphalt, and increased the upper grading (performance) temperature of sulfur asphalt. The combined effect of sulfur and crumb rubber reduced the activation energy compared with that of pure asphalt. Zero‐shear viscosity and strategic highway research program rutting parameter (G*/sinδ) improved by crumb rubber incorporation into the sulfur asphalt binder. Short‐term aging improved G*/sinδ with slight increase in activation energy. The addition of sulfur to asphalt matrix increased the viscoelastic properties (G′ and G″) of sulfur asphalt. The addition of crumb rubber to sulfur asphalt enhanced the temperature resistance of the binder. Utilization of waste crumb rubber and sulfur in asphalt modification proved to enhance asphalt pavement life. In addition, utilization of such wastes can help in meeting the extra demand for asphalt, reduce the pavement cost, and help in solving a waste disposal problem. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40046.     

离子液体介质中沥青砂内重组分降解过程

This paper illustrates the reaction pattern of catalytic degradation of macromolecules in asphaltic sands. Such parameters as ionic liquid catalyst system and H^ proton donor, that affect the change of the organic phase and the mass of organic matter in residual phase of asphaltic sands, were investigated. It was found that chloroaluminate (Ⅲ) ionic liquid/H3PO4 systems as reaction medium was an effective catalyst system for asphaltic sands degradation. The catalytic degradation of asphaltic sand swas related to the kinds of chloroaluminate (Ⅲ) ionic liquids and H^ proton donor. In [BMIM] [AlCl4]/H3PO4 reaction catalytic medium, the degradation of asphaltenes in the organic phase reached 16.44 %, the degradation of asphaltenes in the residual phase reached 30.74%. TLC-FID analysis of asphaltic sands showed that the main degradation products were saturates and aromatics, and resin fractions as well. At a temperature close to oil-bearing formation and with absense of oxygen, the yield of H2S reached 74%,which indicated that catalytic degradation of sulphur-containing compounds was easier.     

Rheological properties of packaging‐waste‐polyethylene‐modified asphalt

Waste‐polyethylene (WPE) in packaging, instead of virgin polymer, was utilized as a modifier of base asphalt, and rheological properties of the modified asphalt were studied. Results show that the modified asphalt possesses better anti‐distortion capacity than the base asphalt, as indicated by the fact that the modified asphalt has higher viscosity and smaller endothermic peak dispersion in the transformation process of asphalt aggregation. Compared with base asphalt, the modified asphalt has higher complex modulus (G*), storage modulus (G′), and dissipation modulus (G″). In addition, the modified asphalt has smaller phase angle (δ), less tangent (tanδ), and lower rut factor (G*/sinδ), reflecting the high‐temperature rut resistance of the asphalt. The improvement of the rheological properties is related to the main features of the modified asphalt, including the swelling, whereas packaging‐waste‐PE absorbs low‐molecular‐weight fractions of asphalt, the displacement restriction of asphalt particles, and the molecular structure and performance of PE molecules. J. VINYL ADDIT. TECHNOL., 21:215–219, 2015. © 2014 Society of Plastics Engineers     

Characterization of Culturable PAH and BTEX Degrading Bacteria from Heavy Oil of the Rancho La Brea Tarpits

Novel petroleum degrading bacteria have been identified in heavy oil from natural asphalt seeps using DNA-based methods, but there is little knowledge of the extent to which these bacteria can be cultured by selective enrichments on different aromatic hydrocarbons. Here we report the species composition of bacterial communities from a 40,000 yr-old asphalt deposit that could be grown on selected petroleum compounds. Species compositions of the degrader communities determined by PCR-DGGE and 16S rDNA sequencing showed that selective enrichment using (PAHs) and BTEX (benzene, toluene, ethyl benzene, and xylene) as growth substrates produced relatively simple degrader communities, and included a predominant species, Pseudomonas stutzeri, which grew on multiple compounds. PCR-based techniques further identified genes encoding naphthalene dioxygenase and catechol 2,3-dioxygenase from P. stutzeri in the enrichment cultures. The results suggest that only a small portion of the asphalt-inhabiting community can be cultured under aerobic conditions on individual substrates. Within these communities were several new species that merit further characterization as consortia, as well as new isolates of the cosmopolitan degrader, P. stutzeri.     

Asphalt modified by SBS triblock copolymer: Structures and properties

Microstructural transformation of a poly(styrene-b-butadiene-b-styrene), SBS, triblock copolymer blended with asphalt was studied as the asphalt composition was varied from 0 wt% to 96 wt%. Transmission electron microscopy (TEM), dynamic mechanical spectrometry (DMS), and differential scanning calorimetry (DSC) were used. The blends were made in batch mixers at 200°C, or by solution casting from a nonselective solvent (trichloroethane) at ∼28°C. Asphalt partially solubilizes the polybutadene (PB) midblock of the SBS producing saturated PB microdomains along with macrodomains of asphalt. When the asphalt concentration was varied from 10 to 90 wt%, the asphalt phase separated into a variable number of large domains, while the SBS-rich regions formed a continuous matrix. Networks of SBS-rich regions were observed at low magnification; these are referred to as macro-networks. At higher magnification, networks that are stabilized by polystyrene (PS) microdomains (denoted micro-networks) are also formed. The presence of a macro-network is also confirmed by stress relaxation tests. The macro-network broke down into microgel-like structures when the asphalt composition exceeded 90 wt%. Examination of the interior of the SBS-rich regions showed that the shape of the PS microdomains transformed from short cylinders to lamellae, hexagonally perforated lamellae (HPL), back to lamellae, short cylinders, and finally to spheres. DMS and DSC indicate a systematic increase in the PB glass transition temperature (T_g) and negligible change in the T_g of PS as the asphalt content increases. Triblock copolymers that can form a macro-network at low concentration will be more desirable for highway pavement modification.     

Internal structure of bitumen/polymer/wax ternary mixtures for warm mix asphalts

Polymer modified asphalts (PMA) and warm mix asphalts (WMA) are technologies widely adopted in the paving industry. The first one is well established, while the second one is relatively new, but rapidly growing since it guarantees economic and environmental advantages. Until now PMA and WMA have been used disjointedly, but it would be useful to combine them to keep the advantages of both. One of the adopted solutions to obtain a warm effect is the addition of waxes to the asphaltic binder. Therefore, a “warm mix polymer modified asphalt” may be potentially obtained with a ternary asphalt/polymer/wax system. However, the final warm effect and performances of the binder will depend on the interactions between the three components. A preliminary investigation was done by mixing asphalt, styrene‐butadiene‐styrene block copolymer and a wax chosen among the following three categories: paraffinic, partially oxidized and maleic anhydride functionalized. The morphological and calorimetric analyses and solubility tests allowed identifying different behaviors depending on the wax type, which may preferentially interact either with the asphalt or with the polymer, thus influencing the whole binder structure. With regard to the ternary mixes, it was found that: (i) the paraffinic wax preferentially resides in the polymer‐rich phase, and slightly enhances the asphalt‐polymer compatibility; (ii) the partially oxidized wax prefers the asphaltene‐rich phase and reduces the compatibility; (iii) it is not clear where the functionalized wax is located, but it has a considerable compatibilizing effect and strongly alters the colloidal equilibrium of the asphalt‐polymer blend. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Crumb tire rubber and polyethylene mutually stabilized in asphalt by screw extrusion

In order to put recycled rubber and plastics into practical use for asphalt's modification, the polyethylene (PE)/crumb tire rubber (CTR) blends were blended to prevent them from phase separation in asphalt during hot storage. The effect of screw extrusion on storage stability, morphology, and thermal properties of modified asphalt were investigated. The results showed that the storage stability of PE/CTR modified asphalt was significantly improved after screw extrusion in the presence of a compatibilizer. The extruded PE and CTR were more finely and uniformly dispersed in the asphalt. The rheological properties of modified asphalts were improved at both higher and lower temperature's range. The density discrepancy between asphalt and the extruded PE/CTR particles was neutralized by the combination between PE and CTR. The interactions among PE, CTR and asphalt were improved by the compatibilizer. Both the reduction of density difference and the enhanced interactions are critical to obtain a stable modified asphalt system. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41189.     

Investigation of epoxy‐resin‐modified asphalt binder

Epoxy asphalt (EA) binder has been used extensively for paving long‐span bridges in many countries because it shows excellent heat resistance, is free from bleeding, has a low‐temperature cracking resistance, and has aggregate scattering resistance. EA binders were prepared by the mixture of asphalt, epoxy resin, and a new curing agent (CR) with functional groups. The properties of the EA binder were characterized by their viscosity, tensile strength, elongation at break, compatibility, morphology, glass transition temperature (T_g), contact angle, and surface free energy. The curing process was analyzed. The results indicate that the curing temperature and asphalt content had significant effects on the properties of the EA binder. We observed that most of the strength was generated after the first 3 h at 165 °C; this provided good workability for EA pavement construction. The CR with various functional groups improved the compatibility and morphology of the EA binder. The test results show that T_g of the EA binder decreased and the contact angles increased with increasing asphalt content. It is worth noting the contact angles between water and the EA binder were always greater than 90°; this implied that the EA binder was hydrophobic and, hence, water repellent. The surface free energy and dispersion force increases with decreasing asphalt content. However, the polarity forces decreased with decreasing asphalt content. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43401.     

Synthesis and antibacterial activity of copolymers having a quaternary ammonium salt side group

Copolymers with a quaternary ammonium salt side group have been prepared from vinylbenzyl–cetyldimethylammonium chloride and acrylonitrile and their antibacterial activity has been examined with Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. Growth inhibitory effect has been found to increase with the increase in the quaternary ammonium salt concentration in the copolymer. The effect is small on gram-negative bacteria and large on gram-positive bacteria.     

Analysis of performance and mechanism of Buton rock asphalt modified asphalt

The performance and modification mechanism of Buton rock asphalt (BRA) modified asphalt were analyzed. The road performance of modified asphalt was observed and compared with SBS modified asphalt to confirm the modification mechanism. Four-component test, and dynamic shear rheological tests were conducted to identify the performance of modified asphalt. Fourier transform infrared spectroscopy was carried out to analyze the modification mechanism of modified asphalt. Finally, the rutting, low-temperature bending beam failure, and freeze–thaw splitting tests were used to evaluate the high-temperature performance, low-temperature cracking resistance, and water stability performance of mixtures, respectively. The results show that the high-temperature performance of asphalt can be improved by BRA with asphaltene and resin increased. It is likely that there is no new functional group generated and this process was physical changes mainly. The honeycomb structure of BRA ashes/particles increased the contact area between the base asphalt and BRA ashes/particles, which makes the asphalt change from the homogeneous body into a two-phase continuous structure system. Consequently, the adhesion between asphalt and BRA ashes/particles was enhanced, and the dynamic stability, bending coefficient and splitting strength ratio were improved. It indicates that the test results of asphalt mixtures verified the modification effect of BRA. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46903.     

The research for high‐elastic modified asphalt

High‐elastic modified (HEM) asphalt was prepared by the addition of styrene‐butadiene‐styrene (SBS), plasticizer, and crosslinker to base asphalt. The effect and proportion of each modifier in asphalt were studied using physical and rheological tests. It was found that SBS determined the high‐temperature performance of HEM asphalt mainly. Plasticizer (dioctyl phthalate) is very helpful in improving the low‐temperature flexibility and elastic recovery. Crosslinker (sulfur) is necessary in maintaining high‐temperature stability. In this study, Fourier transform infrared, hydrogen nuclear magnetic resonance analysis, and microscopy observation were used to investigate the structural characteristics of modified asphalts further before and after ageing. The research showed the structural characteristics of modified asphalt were influenced evidently by ageing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42132.     

The Anti-Adherent Activity of Plant Extracts on Penicillium Commune Spores Causing Cedar Wood Decay: An ESEM Analysis

Decay and deterioration of wood by bacteria and fungi are becoming very serious problems because of the resistance of microorganisms to antimicrobial agents. Thus, this study was aimed at investigating the anti-adhesion effect of Myrtus communis and Thymus vulgaris extracts obtained by classical and ultrasonic extraction, against of Penicillium commune spores isolated from fez Medina cedar wood. According to environmental scanning electron microscopy (ESEM) analysis, the results showed that all extracts tested have proven their ability to inhibit the adhesion of the fungal spores studied. In addition, the extract of each plant obtained by ultrasonication showed a low percentage (47% and 33%) of fungal spores adherent to a wood substrate compared to those recovered by maceration (68%). Furthermore, M. communis extracts have shown outstanding anti-adhesive activity, similar to that demonstrated by those of T. vulgaris. Finally, the treatment of wood by M. communis extracts obtained by ultrasonication showed a very important anti-adhesive activity at a concentration of 20 mg/mL compared to that at 5 mg/mL. Therefore, these extracts can be considered a potential source of bioactive metabolites acting as anti-adhesion molecules in novel formulations for the cedar wood preservation.     

Effects of epoxy resin contents on the rheological properties of epoxy‐asphalt blends

Epoxy‐asphalt and its mixture have been proposed for the long span orthotropic steel deck bridges because it shows excellent heat resistance, free from bleeding, low temperature cracking resistance, and aggregate scattering resistance. In this study, the effects of epoxy resin contents on rheological properties of epoxy‐asphalt binders were studied using dynamic shear rheometer. Experimental results indicated that the improvement of the viscoelastic performance of asphalt binder is noticeable at high temperatures, at which the elasticity is increased (higher G* and lower δ) for epoxy‐asphalt with increase in epoxy resin contents. The viscous behavior of the asphalt also increased when epoxy resin is added. Creep test results indicated that epoxy‐asphalt binder can not only resist deformation at elevated temperatures but recover satisfactorily from strain. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Rubber‐like thermosetting epoxy asphalt composites exhibiting atypical yielding behaviors

Rubber‐like thermosetting epoxy asphalt composites (REACs) were prepared by curing epoxy resin (diglycidyl ether of bisphenol A) with curing agents system made up of maleated petroleum asphalt, adipic acid, and methylhexahydrophthalic anhydride. REACs' glass transition temperatures (T_g) and mechanics performances were investigated by differential scanning calorimetry (DSC) and universal tester, respectively. DSC results indicated that REACs had homogeneous phase structures, and their T_g were lower than room temperature. Large elongation at break (ε_b), as high as 150–286%, and atypical yielding behaviors similar to so‐called “hard elastic” thermoplastics were observed simultaneously for the first time as to thermosetting epoxy composites at room temperature. The striking characteristics of REACs were ascribed to the formation of unique asphalt‐filled bimodal networks, consisting of simultaneous cured maleated asphalt short‐chain and dicarboxylic acid long‐chain interpenetrating bimodal networks and wherewith filled unmaleated asphalt. The experimental results suggest that these inexpensive REACs may find promising applications in many engineering fields. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Chemical deterioration and discoloration of semi-dried tilapia processed by sun drying and microwave drying

Drying methods can affect the chemical deterioration and discoloration of fish muscle. This study aimed to monitor the effect of microwave drying at different effective powers in comparison with sun drying on the physicochemical changes of semidried tilapia. Lipid deterioration, protein oxidation and discoloration of semidried tilapia (Oreochromis niloticus) muscle processed by sun drying and microwave drying were investigated. Results of the study revealed that the pH of microwaved tilapia was higher than that of the sun-dried tilapia (p?p?p?p?p?p?a* value with a significantly decreased redness index (p?相似文献   

Influence of ageing on viscoelastic properties of PMMA/ATH modified bitumen

This article deals with the influence of the ageing treatment on the viscoelastic behavior of PMMA/ATH modified paving bitumen. Waste composite powder (polymethyl methacrylate filled with aluminium trihydrate)—PMMA/ATH and Fischer–Tropsch wax were used as modifying agents for 70/100 paving grade bitumen. Measurements in intermediate temperature range were carried out under oscillatory shear conditions on a dynamic shear rheometer (DSR). Creep testing in low temperature range was conducted on a bending beam rheometer (BBR). The time‐dependent behavior of investigated samples was presented in a form of relaxation moduli G(t) and E(t). Dynamic moduli, i.e., G′(ω) and G″(ω), were converted to relaxation modulus G(t) using the Schwarzl method. The interconversion between tensile creep compliance D(t), and tensile relaxation modulus E(t) was performed using the Hopkins and Hamming approach. It was found that modified binders are less susceptible to the oxidation process during bitumen ageing, since the viscoelastic properties changed less than for the base bitumen. Our results indicate that the use of waste PMMA/ATH in the selected bitumen altered the time‐dependent deformation behavior of asphalt binder. The effect of ageing treatment on material functions was particularly manifested at longer times. Different stress relaxation behavior of modified binders could result in higher deformation resistance of asphalt mixture. POLYM. COMPOS., 36:1738–1747, 2015. © 2014 Society of Plastics Engineers