Asphalt Pavements Research Papers - Academia.edu (original) (raw)

Recent advances in the understanding of the molecular and colloidal structure of asphaltenes in crude oils are codified in the Yen−Mullins model of asphaltenes. The Yen−Mullins model has enabled the development of the industry's first asphaltene equation of state for predicting asphaltene concentration gradients in oil reservoirs, the Flory−Huggins−Zuo equation of state (FHZ EOS). The FHZ EOS is built by adding gravitational forces onto the existing Flory−Huggins regular solution model that has been used widely to model the phase behavior of asphaltene precipitation in the oil and gas industry. For reservoir crude oils with a low gas/oil ratio (GOR), the FHZ EOS reduces predominantly to a simple form, the gravity term only, and for mobile heavy oil, the gravity term simply uses asphaltene clusters. The FHZ EOS has successfully been employed to estimate the concentration gradients of asphaltenes and/or heavy ends in different crude oil columns around the world, thus evaluating the reservoir connectivity, which has been confirmed by the subsequent production data. This paper reviews recent advances in applying the FHZ EOS to different crude oil reservoirs from volatile oil (condensate) to black oil to mobile heavy oil all over the world to address key reservoir issues, such as reservoir connectivity/compartmentalization, tar mat formation, non-equilibrium with a late gas charge, and asphaltene destabilization. The workflow incorporates the integration of new technology, downhole fluid analysis (DFA), coupled with the new scientific advances, the FHZ EOS and Yen−Mullins model. The combination proves a powerful new method of reservoir evaluation. Asphaltene or heavy end concentration gradients in crude oils are treated using the FHZ EOS, explicitly incorporating the size of resin molecules, asphaltene molecules, asphaltene nanoaggregates, and/or asphaltene clusters. All of the parameters in the FHZ EOS are related to DFA measurements, such as compositions, GOR, density, etc. The variations of gas and oil properties with depth are calculated by the classical cubic equation of state (EOS) based on DFA compositions and GOR using specifically developed delumping, characterizing, and oil-based drilling mud (OBM) contamination correcting techniques. Field case studies have proven the value and simplicity of this asphaltene or heavy end treatment. Heuristics can be developed from results corresponding to estimation of asphaltene gradients. Perylene-like resins with the size of ∼1 nm are dispersed as molecules in high-GOR volatile oils with high fluorescence intensity and virtually no asphaltenes (0 wt % asphaltene). Heavy asphaltene-like resins with the size of ∼1.3 nm are molecularly dissolved in volatile oil at a very low asphaltene content. Asphaltene nanoaggregates with the size of ∼2 nm are dispersed in stable crude oil at a bit higher asphaltene content. Asphaltene clusters are found in mobile heavy oil with the size of ∼5 nm at even higher asphaltene content (typically >8 wt % based on stock tank oil). Two types of tar mats are identified by the FHZ EOS: one with a large discontinuous increase in asphaltene content versus depth typically at the base of an oil column (corresponding to asphaltene phase transition) and one with a continuous increase in asphaltene content at the base of a heavy oil column simply by extending the oil column in the downdip direction because of an exponential increase in viscosity with asphaltene content. All of these studies are in accordance with the observations in the Yen−Mullins model within the FHZ EOS analysis.

- by and +1
- •
- Reservoir Characterization, Asphaltenes, Asphalt Pavements, Oil and Gas Reservoir Characterization

The asphalt industry has been under pressure to reduce its emissions. This can be achieved, from one hand, by decreasing the mixing and laying temperatures of asphalt mixtures. On the other hand, recycling of Reclaimed Asphalt Pavement (RAP) is a viable solution that allows reducing waste production and resources consumption. This paper presents a study that combines Warm Mix Asphalt with the use of RAP aggregates. These mixtures, while being produced at lower temperature than traditional Hot Mixtures contain 100% RAP. Several Warm Mix Recycled Asphalt (WMRA) were prepared with 100% RAP and different emulsion contents and their behaviour was assessed by means of laboratory tests such as water sensitivity, stiffness, fatigue resistance and rutting resistance. The obtained results show that these WMRA may be successfully used in road pavements in substitution of conventional Hot Mix Asphalts.

- by João Castro-Gomes and +2
- •
- Pavement Materials, Pavement Engineering, Asphalt Pavements, WMA, warm mix asphalt

‫ال‬ ‫ولخص‬ ‫ٌٍىُ‬ ‫نظشا‬ ‫اٌّصشُ‬ ‫اٌسٌق‬ ‫فِ‬ ‫اٌّعشًض‬ ‫االسفٍث‬ ‫فِ‬ ‫ٍِحٌظ‬ ‫نمص‬ ‫حذخ‬ ‫اٌّحضاّذ‬ ٌ ‫ّششًعات‬ ‫إ‬ ‫اٌطشق‬ ‫نشاء‬ ‫اللي‬ ‫خ‬ ‫اٌحاٌِ‬ ‫اٌعمذ‬ ‫ِّا‬ ‫اٌِ‬ ‫أدُ‬ ‫إ‬ ‫ا‬ ‫سحْشاد‬ ‫اٌخاسز‬ ‫ِن‬ ‫السفٍث‬ ً ‫اٌصعبة‬ ‫اٌعٍّة‬ ‫ِشىٍة‬ ‫فحفالّث‬ ‫جضاّذت‬ ‫أ‬ ‫سعاس‬ ‫ه‬ ‫اٌّحٍْة‬. ‫الىٍة‬ ‫ِش‬ ‫ىنان‬ ‫الو‬ ‫ال‬ ‫ان‬ ‫الَ‬ ‫ال‬ ‫ى‬ ً ‫الشه‬ ‫ال‬ ‫خطْ‬ ‫الشٍ‬ ‫ال‬ ‫أخ‬ ‫ال‬ ‫ال‬ ٌ ‫الذ‬ ‫ال‬ ‫ل‬ ‫ٌحع‬ ‫إ‬ ‫الذد‬ ‫ال‬ ‫اٌحخ‬ ‫الاس‬ ‫ال‬ ‫نحش‬ ‫الذد‬ ‫ال‬ ‫ع‬ ‫الِ‬ ‫ال‬ ‫عٍ‬ ‫الش‬ ‫ال‬ ‫وبْ‬ ‫الذّرا‬ ‫ال‬ ‫ح‬ ‫ه‬ ‫ال‬ ‫ال‬ ‫اٌّنش‬ ‫الشّة‬ ‫ال‬ ‫اٌّص‬ ‫الشق‬ ‫ال‬ ‫اٌط‬ ‫الن‬ ‫ال‬ ِ ٌ ‫الشا‬ ‫ال‬ ‫نظ‬ ‫الاده‬ ‫ال‬ ‫ضّ‬ ‫البة‬ ‫ال‬ ‫نس‬ ‫الات‬ ‫ال‬ ‫ِشوب‬ ‫الً‬ ‫ال‬ ‫نم‬ ‫الا‬ ‫ال‬ ‫اٌبض‬ ‫الاده‬ ‫ال‬ ‫صّ‬ ً ‫األ‬ ‫الة‬ ‫ال‬ ‫اٌّحٌسّ‬ ‫الاي‬ ‫ال‬ ‫حّ‬ ‫الً‬ ‫ال‬ ‫اٌنم‬ ‫الَ‬ ‫ال‬ ‫عٍ‬ ‫الاد‬ ‫ال‬ ‫االعحّ‬ ‫الاده‬ ‫ال‬ ‫صّ‬ ‫البز‬ ‫ال‬ ‫بس‬ ‫الا‬ ‫ال‬ ‫ٌٍبض‬ ‫الشٍ‬ ‫ال‬ ‫اٌب‬. ‫الاٌِ‬ ‫ال‬ ‫باٌح‬ ‫أ‬ ‫الن‬ ‫ال‬ ِ ‫البم‬ ‫ال‬ ‫ص‬ ‫حً‬ ‫عن‬ ‫اٌبحد‬ ‫اٌضشًسُ‬ ‫ّىفً‬ ‫إ‬ ‫سصف‬ ‫سححذاخ‬ ‫أ‬ ‫سفٍحِ‬ ‫را‬ ‫ِححٌُ‬ ‫أ‬ ‫الذسه‬ ‫ل‬ ً ‫الفٍث‬ ‫االس‬ ‫الن‬ ِ ‫الً‬ ‫ل‬ ‫أ‬ ‫الِ‬ ‫عٍ‬ ٌ ‫الذد‬ ‫اٌحخ‬ ‫الة‬ ‫ّماًِ‬. ‫الذ‬ ‫جي‬ ‫الزه‬ ‫ال‬ ‫ى‬ ‫الة‬ ‫ال‬ ‫اٌذساس‬ ‫إ‬ ‫الِ‬ ‫ال‬ ٌ ً ‫الْف‬ ‫ال‬ ‫جٌص‬ ‫الُّْ‬ ‫ال‬ ‫جص‬ ‫اٌ‬ ‫الن‬ ‫ال‬ ِ ‫الٌم‬ ‫ال‬ ‫ن‬ ‫الات‬ ‫ال‬ ‫خٍط‬ ‫اال‬ ‫الفٍحْة‬ ‫ال‬ ‫س‬ ‫الٌُ‬ ‫ال‬ ‫ِحح‬ ‫رات‬ ‫أ‬ ‫لٍ‬ ‫الفٍحِ‬ ‫ال‬ ‫س‬ ‫البْا‬ ‫ال‬ ‫نس‬ ‫الً‬ ‫ال‬ ْ ‫الة‬ ‫ال‬ ‫ِماًِ‬ ً ‫أ‬ ‫الذد‬ ‫ال‬ ‫ٌٍحخ‬ ‫الِ‬ ‫ال‬ ‫عٍ‬ ‫ا‬ ‫بغشض‬ ‫إل‬ ‫ج‬ ‫فِ‬ ‫سحخذاَ‬ ‫ٌححمْك‬ ‫اٌسطحْة.‬ ‫اٌطبمات‬ ‫نفْز‬ ‫الُ‬ ‫ج‬ ‫اٌذساسة‬ ‫أىذ‬ ‫الٌء‬ ‫اٌٍص‬ ‫إ‬ ‫الِ‬ ٌ ‫إ‬ ‫الن‬ ‫حم‬ ‫الٌٍ‬ ‫س‬ ٌ ‫الاي‬ ‫ِاسا‬ ‫الز‬ ‫لٌاٌ‬ ‫الات‬ ‫ٍخٍط‬ ‫االسفٍحْة‬ ‫اٌنفارّة‬ ‫اٌعاٌْة‬ ‫ِخحٍفة‬ ‫دِه‬ ‫طالات‬ ‫ذْش‬ ‫بح‬ ‫اٌّنحصة‬ ‫ب‬ ‫الن‬ ‫حم‬ ‫ٌِاد‬ ‫اسحخذاَ‬ ‫الة‬ ‫ِحٍْ‬. ‫أ‬ ‫الاجس‬ ‫ن‬ ‫الً‬ ‫سِ‬ ً ‫الشٍ‬ ‫اٌصْ‬ ‫الش‬ ‫اٌحص‬ ‫الحخذَ‬ ‫س‬ ‫اٌصْشٍ‬ ‫اٌحصش‬ ‫بٌدسه‬ ً ‫اٌىساسات‬ ‫اٌنف‬ ‫عاٌْة‬ ‫خٍطات‬ ‫العذاد‬ ً ‫ارّة‬ ‫الث‬ ‫جح‬ ‫الة‬ ‫اٌٌالع‬ ‫الات‬ ‫ٌٍخٍط‬ ‫الّّْْة‬ ‫اٌحص‬ ‫الفٍث‬ ‫االس‬ ‫البة‬ ‫نس‬ ‫حسبث‬ ‫اٌفحص‬ ‫الَ‬ ‫اٌسٍْس‬ ‫اٌشًِ‬ ً ‫االسّنث‬ ‫ِخٌٍط‬ ً ‫باالسّنث‬ ‫حمنيا‬ ‫جُ‬ ً ‫ٌٍخٍطات‬ ‫ِاسااي‬ ‫لٌاٌز‬ ‫أعذت‬ ‫نظشّا.‬ ‫الُ‬ ‫ذ‬ ‫الة‬ ‫ِخحٍف‬ ‫الز‬ ‫بنس‬ ‫أششّث‬ ‫عٍْيا‬ ‫إ‬ ‫خحباسات‬ ً ‫ِحاط‬ ‫اٌغْش‬ ‫اٌضغظ‬ ‫الات‬ ‫اٌرب‬ ً ‫اليا‬ ‫ص‬ ‫خصا‬ ‫الِ‬ ‫عٍ‬ ‫الش‬ ‫ٌٍحع‬ ‫الش‬ ‫ِباا‬ ‫الش‬ ‫اٌغْ‬ ‫الذ‬ ‫اٌش‬ ‫الْة‬ ‫اٌينذس‬ ‫و‬ ‫الا‬ ّ ‫أ‬ ‫الث‬ ‫ششّ‬ ‫جمٍْذّة‬ ‫خٍطة‬ ‫عٍِ‬ ‫االخحباسات‬ ‫نفس‬ ‫جذسز‬ ‫رات‬ 4 ‫اٌٌّاد‬ ‫بنفس‬ ‫ز‬ ‫صي‬ ‫نحا‬ ‫السحخذاَ‬ ‫ا‬ ٌٍ ‫ّماسنة.‬ ‫الة‬ ‫فاعٍْ‬ ‫الد‬ ‫اٌبح‬ ‫س‬ ‫الا‬ ‫نح‬ ‫الً‬ ‫جحٍْ‬ ‫الْن‬ ‫ب‬ ‫جىنٌٌٌشْا‬ ‫اٌ‬ ‫حمن‬ ‫بنسبة‬ ‫ناعُ‬ ‫اٌشًِ‬ ِ ‫ًِخٌٍطو‬ ‫اٌعادُ‬ ‫اٌبٌسجلنذُ‬ ‫االسّنث‬ ‫ِن‬ ‫بىً‬ 1:1 ‫الِ‬ ‫ف‬ ‫الن‬ ِ ‫الاّمش‬ ِ ‫الٌفْش‬ ‫ج‬ 53 ‫الِ‬ ‫اٌ‬ 44 ‫اٌّطٍ‬ ‫االسفٍث‬ ‫وّْة‬ ‫ِن‬ % ‫ٌبة‬ ‫الا‬ ‫بّ‬ ‫الات‬ ‫اٌرب‬ ً ‫اٌضغظ‬ ‫ِماًِة‬ ‫صّاده‬ ‫خلي‬ ‫ِن‬ ‫ٌٍحخذد‬ ‫اٌنفارّة‬ ‫اٌعاٌْة‬ ‫اٌخٍطات‬ ‫ِماًِة‬ ‫ًسف‬ ‫ّعادي‬ 5 ‫اٌحمٍْذّة.‬ ‫االسفٍحْة‬ ‫ٌٍخٍطات‬ ‫اٌّناظشه‬ ‫اٌمُْ‬ ‫أضعا‬ Abstract A noticeable shortage was occurred in the asphalt supply in the Egyptian Market due to the increasing volume of road construction projects in the current decade, which led to importing asphalt from foreign countries. Consequently, aggravates the problem of hard currency and increasing the local asphalt prices. Another serious problem has been also observed on unlimited number of newly constructed Egyptian roads, that is the rutting distress due to the increasing of both of percentage of goods truck and axle loads accompanied by the increasing of goods transported via the Egyptian highway networks. So, finding out a solution to develop mixtures that have lower asphalt contents and high resistance to the rutting becomes essential. This study aims at characterization and design special type of asphalt mixture having lower asphalt content and of higher rutting resistance to be used in paving surface layers. To achieve this objective, grouting technique of highly permeable asphalt mixtures produced under different compacting efforts was used. Crushed limestone, crushed sand, and limestone filler were used to prepare highly permeable asphalt mixtures. Asphalt contents of these mixes were determined theoretically. Marshall moulds representing these mixes were prepared and grouted using ordinary portland cement (OPC) as well as mixtures of OPC and silica sand with different ratios. Unconfined compressive strength (UCS), Marshall Stability, and indirect tensile strength tests were conducted on these mixes to define their characteristics. The same tests were conducted on crushed limestone traditional mix of 4C gradation for comparison purposes. Analyzing the study results, the active effect of grouting technique using each of OPC as well as mixture of 1 OPC and silica sand was concluded. Reduction from 35% to 44 % of the required asphalt amount and increasing of rutting resistance for highly porous mixes through increasing UCS and stability by about 3 times compared with traditional asphalt mixtures.

- by Mohamed Shalaby
- •
- Highway engineering, Asphalt Pavements

Crumb rubber modifier (CRM) is considered one of the most commonly used modifiers that enhances the rheological properties of asphalt binders. Optimizing the interaction process between CRM and asphalt binder to enhance the asphalt binder’s elasticity without additional additives is the main purpose of the article. Rheological properties were measured in this article for neat asphalt and crumb rubber modified asphalt (CRMA) binders. Two sets of interactions were selected. In the first interaction set, one interaction temperature (190°C), one interaction speed (3,000 rpm), and different interaction times (0.5, 1, 2, 4, and 8 h) were used. The used CRM percentage was 10 % by weight of the neat asphalt binder. Two sources of asphalt binder, one source and different percentages of CRM, one interaction temperature (190°C), one interaction speed (3,000 rpm), and different interaction times were selected for the second interaction set. This set was designated to confirm the rheological properties obtained for the first set. Thermogravimetric analysis (TGA) was performed on CRM particles before and after their interaction with asphalt binder after different interaction times. The CRMA binders that interacted for the entire 8-h interaction times had significantly enhanced properties, especially the elasticity, as compared to the neat asphalt binder. The 8-h interaction time showed the highest CRM dissolution percentage by dissolution and TGA testing. At this interaction time, more CRM components were released into the asphalt binder liquid phase, which was detected by observing Fourier-transform infrared peaks at 966 cm−1 for polypropylene and 699 cm−1 for polystyrene.

- by Eslam M Deef-Allah
- •
- Asphalt, Pavement Materials, Elasticity, Civil Engineering Materials
- by mutiu akinpelu
- •
- Asphalt Pavements, Bituminous Pavement

This study investigates the feasibility and effect of poly(lactic) acid (PLA) on bitumen modification. The chemical and physical properties were evaluated for the modified bitumen produced with varying percentages of PLA ranging from 3 to 9%. Several testings such as the nuclear magnetic resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), Gel permeation chromatography (GPC), penetration, softening and ductility, and thermal storage stability were evaluated. The results show that chemical interaction exists between PLA and bitumen. The GPC analysis indicates high compatibility of the bitumen with the PLA modifier. Moreover, the results indicated that the addition of PLA increased the consistency of modified bitumen. The storage stability and segregation of phases were positively affected in the PLA modified bitumen. The PLA and base bitumen interact at physical and chemical levels which results in enhancement of performance of modified bitumen to produce a high-quality binding material for pavement construction.

which gains its main strength from stone on stone contact. It provides a rut-resistant, durable surfacing material which is suitable for heavily trafficked roads. Typical SMA consists of 70-80 % coarse aggregate, 8-12 % mineral fillers, and 6-7 % binder .
Due to this high binder content, stabilizing additives are needed to prevent draindown that might occur during transport and placement. According to SMA standards, cellulose and mineral fibers are the most suitable stabilizing additives to be used in SMA, but due to lack of those specific types of fibers in some countries, another types of fibers are being tested to replace them in the mix .
The main objective of this study is to investigate the characteristics of SMA mixtures using fiberglass as a stabilizing additive. Another SMA mix of the best result was prepared using polypropylene fiber instead of fiberglass and tested for comparison purposes.
Two different SMA gradations were tested, nominal maximum aggregate size (NMAS) 12.50 mm and NMAS 19.00 mm at four different fiber contents for each gradation 0.00 %, 0.30 %, 0.50 %, and 0.70 % by total weight of the mix. SMA samples were tested through series of performance tests selected to be Marshall stability test, moisture susceptibility test, indirect tensile strength test (ITS), and draindown test .

- by Hassan Mahdy
- •
- Asphalt Pavements, Asphalt Cement Modifier
- by Fan Yin and +2
- •
- Asphalt Pavements

In recent years, the significant importance of solid waste management, increase in the cost of bitumen and polymer modifiers have encouraged the pavement engineers to use reusable alternative sources. Ground tire rubber (GTR) and amorphous carbon powder (ACP) are considered as two industrial waste which their using in asphalt mixture prevents their releasing in the environment. This study aims to analyze moisture sensitivity, fatigue performance, and rutting resistance of asphalt mixture influenced by using GTR (8, 12, and 16% of bitumen weight) as the modifier of bitumen properties, and ACP (25, 50, and 75% of filler weight) as filler. The results of this study shows that the ACP increases the resilient modulus and indirect tensile strength of rubberized asphalt concrete (RAC) mixtures. The results revealed that despite the negative effect of GTR on the moisture resistance of asphalt mixture, ACP improves the moisture performance. The results of fracture energy also implies that using ACP decreases the fracture energy, but using the GTR improves the fatigue resistance of asphalt mixture. Furthermore, the results of dynamic creep and wheel track tests indicates that 16GTR + 50ACP has the lowest permanent deformation and highest rutting resistance. The results of ANOVA analysis demonstrates that using GTR and ACP has a considerable effect on the performance properties of asphalt mixture. Finally, the results of this study illustrate the simultaneous use cleaner production and wasted materials decreases the environmental damages in addition to improvement of physical properties of the asphalt mixture.

Warm Mix Asphalt (WMA) is a practiced technology that allows significant benefits in terms of environment, material, as well as finance. WMA, in comparison to the conventional hot mix asphalt (HMA), promises us various benefits like reducing asphalt usage, lowering mixing and laying temperature, and hence causing significant reduction in the carbon footprints by lowering the greenhouse gas emissions in the atmosphere. Although this technology is widely being used around the world since last two decades, and Guidelines for Warm Mix Asphalt has also been published by the Indian Road Congress in IRC SP 101-2014 but, in India, there is still reservation regarding its adoption and utilization. There is misconception that the bituminous mixture produced at lower temperature will not perform well, may not compact properly, moisture susceptibility will also be affected. There are a number of additives available in the market that proclaim to result in WMA mixes exhibiting the functions mentioned above. Of late, many of the additives claim to enhance the bituminous mixture properties like elastic modulus as well by reducing the air voids and behave as anti-stripping as well. Hence, there is confusion and lack in clarity with regard to the actual functions of the additives resulting in WMA. To streamline the functions of the additives available in the market, we embarked on studying the effects of multiple additives. In this study, three different additives have been used for the WMA production for which both laboratory as well as field study have been done. The additives used to modify the binder are based on amine and organo-silane technology. Post study, it was found that one additive has provided saving in the form of less binder consumption with some reduction in mixing and compaction temperature, while the second has provided benefit in form of enhanced temperature reduction with no effect on asphalt consumption and the third has provided benefit in both asphalt consumption reduction as well as mixing and compaction temperature reduction. The laboratory properties such as Marshall Stability, Indirect Tensile Strength (ITS), Tensile Strength Ratio (TSR), Moisture Susceptibility, Elasticity Modulus etc. with asphalt VG30 and VG40 has also been studied. Also, recycled asphalt pavement (RAP) material utilized in the bituminous mix production contributes partially to the carbon foot print reduction. The normal bituminous mix production temperature as per the Ministry of Road Transport and Highways (MORTH 5 th revision) Specifications is about 160-170ºC and at the time of laying is min 150ºC. All the three additives has provided a reduction in temperature of about 25-35ºC at the time of bituminous mix production and 20-30ºC at the time of laying. The saving in binder is about 0.2 to 0.3%. All the benefits lead towards the reduction in GHG like CO2, SO2, CO, NOx etc. emissions. The detailed paper targets to showcase some of the cost benefits involved in using WMA compared to hot mix for a typical project and provide guidance on the selection of the additive during usage.

- by Yash Pandey
- •
- Asphalt Pavements, WMA, warm mix asphalt
- by Mohamed Karim
- •
- Civil Engineering, Materials Science, Polymers, Experimental Research

Abstract The performance implications of laboratory asphalt loose mixture aging at 135 °C were evaluated by comparing the performance of mixtures subjected to long-term aging at 95 °C and 135 °C to yield the same rheology. Although the rheology of the mixtures aged at 135 °C and 95 °C matched, their chemistry differed. Performance test results suggest that the chemical changes induced by aging at 135 °C can negatively impact performance. The relationship between binder chemistry and rheology was unaffected by aging temperatures at or below 95 °C. The rate of oxidation increased with an increase in temperature, and thus, the optimal loose mixture aging temperature is 95 °C.

- by Michael Elwardany
- •
- Civil Engineering, Materials Science, Asphalt, Pavement Materials

Durability of asphalt pavements is related to choosing proper materials. Fillers as the smallest particles of stone materials, and one of the most important parts of asphalt mixtures, exert pivotal effects on the performance of asphalt mixtures, by filling empty spaces and because of their softness, surface features and chemical compounds. Rice husk ash is one of the waste products of burning rice husk in powerhouses that is accounted as biomass. Recently, a good many of investigations have shown that rice husk ash, as a high quality pozzolan, can be properly replaced of common aggregates. In this study rice husk ash was used as filler in hot mix asphalt, and the result mixtures' mechanical properties was compared with ordinary mixtures whose filler was stone powder. Asphalt mixture samples with two different aggregate graded, and 0, 25, 50, 75 and 100 percent of rice husk ash which were the substitution of stone powder content, were made and the effects of using rice husk ash on the moisture sensitivity, resilience modulus, rutting and dynamic creep of asphalt mixtures were investigated. The results demonstrated that increase of using rice husk ash as the replacement of prevalent fillers in hot mix asphalts, noticeably improves their performance; however, because of excessive stiffness created by rice husk ash, it's better to use it in optimized percentage. Accordingly, statistical analysis of the tests' results leads to presenting an optimized model for the content of Rice Husk Ash to be used in hot mix asphalt. Finally, Rice Husk Ash content were suggested 26% for graded number 4 and 48% for graded number 5 as replacements for stone powder filler.

- by hassan divandari and +1
- •
- Asphalt, Pavement Materials, Pavement Engineering, Pavement design and analysis

Politica de Atlas Copco este de a oferi utilizatorilor echipamentelor acestora cu produse sigure, fiabile și eficiente. Factorii luați în considerare sunt, printre altele:
la destinația și previzibil utilizarea viitoare a produselor, precum și mediile în care acestea sunt de așteptat să funcționeze,
se aplică normele, codurile și reglementările,
durata de viață produs util de așteptat, presupunând service și întreținere corespunzătoare,
oferind manual cu până la informații actualizate.
Înainte de a manipula orice produs, să ia timp pentru a citi manualul de instrucțiuni relevante. În afară de a da instrucțiuni detaliate de operare, de asemenea, oferă informații specifice despre siguranță, întreținere preventivă, etc.
Păstrați manualul întotdeauna la unitatea de locație, ușor accesibil personalului de exploatare.

Binder's response to multiple stress creep and recovery test has been captured. Conventional binders are not suitable for higher temperatures. Modified binders show delayed elastic response. Power law model has been modified to incorporate non-linear viscoelastic response. Critical values for g M and a has been assigned. a b s t r a c t This study investigated the strain response of different asphalt binders when subjected to multiple creep and recovery cycles. Test was conducted at three altered temperatures (40, 50 and 60 °C) and four stress amplitudes (0.1, 3.2, 5 and 10 kPa). Burgers four element model and a Power law model were used to simulate the measured response. It was demonstrated that the modified binders outperformed the conventional binders at all the test conditions. Conventional binders were found to be highly sensitive to change in stress level and temperature. It was proved from the test results that the traditional Superpave criteria for characterizing rutting behavior of asphalt binders is not appropriate. Both the Burgers and Power model gave poor experimental fit for the recovery domain, mainly for the modified binders. The viscous parameter g M of the Burgers model correlated well with the non-recoverable creep compliance (J nR) and R value. The modified Power model, as proposed in the study, was in good agreement with the measured creep and recovery response for all the binders. The new model parameter 'a' was found to be able to predict the delayed elastic response of the binders. Critical values of g M and a were assigned corresponding to different traffic levels and suggested as a rutting measuring tool.

- by Nikhil Saboo
- •
- Pavement Materials, Asphalt Pavements, Bitumen

The scope of this study is to explore and evaluate the effect of reinforcing the interface between the base and asphalt concrete layers in a flexible pavement section with bi-axial geogrids; using both large scale experimental tests and numerical modeling using three-dimensional nonlinear finite elements analysis. A laboratory characterization for each layer of the pavement section according to a laboratory programs that included soil classification, plate loading test, determination of asphalt concrete dynamic modulus for and CBR ratio for different elements in pavement section. A laboratory model of the pavement with and without the geogrid reinforcement, located at the top of the base layer was constructed. A dynamic loading scheme was applied on the experimental pavement model. Concurrently, a numerical model was developed to simulate the effect of such type of reinforcement on the pavement section in terms of the road’s performance enhancement and reduction in rutting. The nume...

Nowadays, a lot of waste glass produced through different sides of life. Applying sustainability has been widely used in different construction materials and flexible pavement was contained different crushed materials through different studies. Crushed glass, where it is nonmetallic and inorganic, it can neither be incinerated nor decomposed, so it may be difficult to reclaim, has been used as filler, fine and coarse aggregates in the asphalt base course. In this study, various standard asphalt tests, such as stability, flow, density and air voids, have been conducted on reference mix asphalt and mix asphalt with different percentages of crushed glass when it has been used as filler, fine and coarse aggregates in the base course. Generally, the results show good indication, especially when using 10% of the crushed glass instead of coarse aggregate with 40-50 asphalt grades. This percentage improves most characteristics such as strength retained index which indicates better performance than reference mix.

- by Hamid Athab Eedan Al-jameel
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- Highway engineering, Asphalt Pavements

Reclaimed asphalt pavement (RAP) is a valuable, high quality material that can be replace over expensive virgin aggregates and binder that can be used for technical, economical and environmental reasons. Use of RAP can be favored all over the world over virgin material on the light of increasing cost of bitumen, the scarcity of high quality aggregates and the pressing need to preserve the environment. Overlay and maintenance resolve medium distress, but reconstruction may feasible and economical while Asphalt pavement are badly deteriorated with time and traffic. This requires the removal of existing pavement surfaces. Recycling such construction waste has benefited from economic to sustainability point of view and reduce the exploitation of natural resources. The shortage of virgin aggregate supplies along with the increase in processing and hauling cost have encouraged the use of reclaimed material from the old structure as base course construction materials and involved in regular practice in various countries around the world.

Rutting is one of the most common distresses in asphalt pavements in Zambia. The problem is particularly prevalent at intersections, bus stops, railway crossings, police checkpoints, climbing lanes and other heavily loaded sections, where there is deceleration, slow moving or static loading. The most widely used methods to identify the source of rutting among flexible pavement layers are destructive methods; field trenching and coring methods. The Transverse Profile Analysis method (TPAM), which is a non-destructive method, was suggested by White et al. in 2002 as an alternative method, to avoid the expensive and destructive nature of the traditional methods. In this method, data from the transverse profile of the rutted section is used to deduce the layer of the pavement structure responsible for rutting failure. This study used the TPAM to determine the layers of pavement responsible for rutting on sections of the Chibuluma and Kitwe-Chingola Roads in Zambia. The method was first validated using the trenching method on the Kitwe-Ndola Road. Results from the TPAM showed good comparability with those from the trenching method. It was established that most of the rutting emanated from the surfacing layer. This is consistent with recent research indicating that most rutting occurs in the upper part of the asphalt surfacing. It was also established that the TPAM was a simpler, faster and less costly method of determining the source of rutting failure compared to the traditional methods.

- by Nathan N Chilukwa and +1
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- Pavement Materials, Pavement Engineering, Road Pavement Engineering and Design, Asphalt Pavements

The end product of asphalt hot mix plants is the hot mix asphalt which is produced by the various combinations of electrical and mechanical components. The cold aggregates are dried, heated and mixed with bitumen and minerals in required proportions to produce the hot mix asphalt. There are stationary as well as mobile asphalt hot mix plants which are used based on the requirements. Apart from it, they can also be categorized into two types-asphalt batch mix plants and the more traditional continuous mixing plant. Though both varieties of plants produce the Hot Mix Asphalt (HMA), the drum mix plants produce continuous HMA, while the batch mix plants produce HMA in batches.

The worksheet ELiCon (version 0.1) performs real-time viscoelastic interconversion in the time and frequency domains. ELiCon accepts as input a four-parameter analytical expression for the uniaxial creep compliance. The time-domain output consists of a list of creep compliance values for certain times, and a corresponding list of relaxation modulus values. The frequency-domain output consists of, for certain frequencies, the norm of the complex modulus and the phase angle.

- by Dr. Costas Sachpazis
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- Civil Engineering, Road safety, Rock Mechanics, Geotechnical Engineering

The method of delivering road maintenance has progressively evolved. Historically, road agencies have moved from using in-house force account to traditional method-based maintenance contracting. Many countries are now heading towards performance-based contracting (PBC), an approach that has been deployed rapidly in the road sector in the past decade. However, while PBC offers a number of benefits for road agencies and road users, it is a relatively new approach and there are several aspects that need careful consideration to ensure that the goals of PBCs are fully achieved. The purpose of this Note is to review the worldwide experience with the PBC approach, highlight the main advantages, the steps involved and the results generated. The document is intended to provide World Bank transport sector staff, Ministries of Transport and road agencies of developing and transition countries with a clear understanding of the benefits, and risks, of applying the PBC approach. A separate Resource Guide (to be released by the World Bank in 2006) will offer more detailed information and resources pertaining to performance-based contracting. The Note has been produced with the financial assistance of a grant from TRISP: a partnership between the United Kingdom Department for International Development and the World Bank for learning and sharing of knowledge in the fields of transport and rural infrastructure services.

- by Laxmipathi Rao Lakkaraju
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- Civil Engineering, Asphalt Pavements, Pavement, Rutting
- by Amir Behravan
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- Asphalt, Polymer Composites, Asphalt Pavements, Asphalt material
- by Mohamed Karim
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- Environmental Engineering, Malaysia, Highway engineering, Fluids

The development of the local end-use market for waste plastic is crucial to increasing South Africa’s plastic recycling rates, especially for low-value, problematic plastic fractions, such as polyolefins consisting mainly of polyethylene and polypropylene. The use of recycled and/or alternative materials such as plastics in road construction is beneficial not only in terms of sustaining the environment, since naturally occurring materials will be conserved but as a means of reducing construction costs. Recycled plastics are being investigated worldwide not only as a green investment, but also for improved pavement durability (Milad et al., 2020). The objectives of the study were to screen, evaluate and implement existing international technologies in line with South African design standards and specifications for materials in road construction. The main research question was whether low value
waste plastics can be optimised as alternative road construction materials in South Africa.

- by Imraan Akhalwaya and +1
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- Pavement Materials, Pavement Engineering, Pavement design and analysis, Road Pavement Engineering and Design

Give an overview of the steel rebars manufacturing scenario and its pros and cons

- by arten dude
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- Asphalt Pavements, Concrete and Hot Mix Asphalt

Asphaltenes, the most aromatic of the heaviest components of crude oil, are critical to all aspects of petroleum utilization, including reservoir characterization , production, transportation, refining, upgrading, paving, and coating materials. The asphaltenes, which are solid, have or impart crucial and often deleterious attributes in fluids such as high viscosity, emulsion stability, low distillate yields, and inopportune phase separation. Nevertheless, fundamental uncertainties had precluded a first-principles approach to asphaltenes until now. Recently, asphaltene science has undergone a renaissance; many basic molecular and nanocolloidal properties have been resolved and codified in the modified Yen model (also known as the Yen-Mullins model), thereby enabling predictive asphaltene science. Advances in analytical chemistry, especially mass spectrometry, enable the identification of tens of thousands of distinct chemical species in crude oils and asphaltenes. These and other powerful advances in asphaltene science fall under the banner of petroleomics, which incorporates predictive petroleum science and provides a framework for future developments.

- by Oliver C Mullins
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- Asphaltenes, Asphalt Pavements, Asphalt material
- by Abdullah Özer
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- Asphalt Pavements

ELLVA1 (Ver 0.83) computes stresses, strains and displacements in a layered viscoelastic half-space due to a uniformly loaded circular area moving with constant speed along a straight line. Five fully bonded weightless, homogeneous, and... more

Fatigue is a major mechanism resulting in flexible pavement distress. Pavement distress results into rutting which lead to structural failure in the asphaltic roads. This is due to axle load applied on the surface of flexible roads and cause permanent pavement deformation. Saad and Ammar (2015) states that the causes of rutting and fatigue in asphalt pavement are a result of accumulation of cracks, aging of binder, repeated axial loading and environmental conditions. The asphalt surfaced roads in Butterworth experience permanent pavement deformation at the asphalt wearing course surface and this result in the decrease of the road service life. The main aim of this research is to investigate the problems associated with rutting and improve the asphalt wearing course surface by selecting the most appropriate asphalt mix design from three selected mixes of unmodified and modified asphalt parameters. These parameters are pure asphalt-60/70 (unmodified control mix design), rubberize asphalt of rubber crumbs blended with bitumen (modified asphalt) and AE-2 polymer modified asphalt (modified asphalt). The objectives of this study were met throught the conduction of laboratory tests which comprised a total of 18 briquettes from the 3 mix design parameters, whereby six (6) briquettes of each mix design were used to test the fatigue resistance of asphalt and its characteristics, through the use of Marshall test and Dynamic creep test. The main parameters that affected the rutting are the volumetric composition of the mix design. The asphalt mix compositions are the aggregate properties, bituminous binder properties, gradation and angularity of aggregate. The volumetric composition affects the voids in mix (VIM) and the stability of the final asphalt mix in place on the roads. The most effective asphalt mix design was rubberized asphalt. This is due to the properties of the rubber crumb binder to display good characteristics of high VIM and high stiffness thus resisting fatigue on the road. This extends the service life of asphalt roads and performs well under heavy traffic load

- by GJESR Journal and +1
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- Civil Engineering, Asphalt, Deformation, Asphalt Pavements

Warm mix asphalt (WMA) is gaining popularity due to its lower production and laying temperatures that benefits the environment. This paper presents the effects of a surfactant based warm additive, Cecabase ® , on the rheological properties of asphalt binder and mixture compactibility. The rheological properties of asphalt binder were measured using a rotational viscometer and dynamic shear rheometer (DSR). Asphalt mixture compactibility was evaluated during compaction using the gyratory compactor based on the degree of compaction and compaction energy index (CEI). From the viscosity and DSR test results, the surfactant based warm additive has no effect on the binder rheology. The compactibility test results shows that all of the WMA mixtures exhibit better compactibility than the hot mix asphalt (HMA). The results shows that it requires less effort to compact WMA at 140°C compared with HMA compacted at 170°C. The CEI results show that it will take more energy to compact HMA specimens compared with compacting WMA at different temperatures. Mixtures with lower CEI exhibits better constructability and are desirable, while too low CEI could be an indication of a tender mixture and should be avoided.

- by Muhammad Rafiq Khan Kakar
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- Asphalt Pavements

h i g h l i g h t s Marshall Test results show that 4.6% Gilsonite increase Marshall Stability. The indirect tensile test indicates the performance improvement of mixture made with Gilsonite. Test result indicates that the addition of Gilsonite to mixtures reduces moisture sensitivity. The specimens with Gilsonite have better performance to those made with pure bitumen 70-60. a b s t r a c t Iran-produced bitumen under the circumstances of severe temperature fluctuation, heavy traffic load and raining/freezing conditions show low efficiency; therefore, it is necessary to improve its properties accordingly. Existence of weakness in produced bitumen result in failure occurrence in asphalt pavements during service life of asphalt roads. Given the existence of considerable reserves of Gilsonite in Iran, its low costs compared with other additives and its remarkable properties, we can study asphalts modified by Gilsonite. At the present time, little research has been conducted on this modifier in the world and Iran (which its properties are still not quite evident for researchers). The most important failure in flexible pavements is permanent deformations which are known as rutting. Rutting is longitudinal depression in the wheel path in bituminous pavements. The rate and depth of rutting depend on the internal factors such as bitumen properties, aggregate, mixture properties and thickness of pavement layers. In this lab study, with regard to the technical and executive issues, common functional performance-based tests of bitumen were performed on specimens through adding Gilsonite with 0, 2, 4, 6, 8, 10 wt.% of made bitumen specimens. Then, the optimum percentage was calculated using the AHP. The specimens containing pure bitumen 60-70 and modified bitumen 60-70 with Gilsonite in two different aggregations (4 and 5) were made and the effects of adding Gilsonite in Marshall Stability and flow, indirect tensile strength and moisture sensitivity, as well as dynamic creep, and resilient modulus were evaluated by the UTM device. The research showed that adding Gilsonite to bitumen in hot asphalt mixtures considerably increases Marshall Stability and resilient modulus parameter in asphalt specimens. However, resilient modulus test indicated a significant reduction in flexibility property of asphalt mixtures made of modified bitumens. Moreover, increasing the flow number obtained from the dynamic creep test indicate the increase of rutting resistance.

- by hassan divandari
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- Asphalt, Pavement Materials, Pavement Engineering, Pavement design and analysis

ASTM Tables for Penetration & Viscosity Grades and Different bet. Penetration & Viscosity Grades

- by Osama Hassan
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- Asphalt Pavements, Bitumen, Marshall, HIGHWAY ROADS AND BRIDGES

Crude oils consist of dissolved gases, liquids,
and dissolved solids—the asphaltenes. The chemical
identity and thermodynamic treatment of gas and liquid
components of crude oil have long been understood. For
example, the cubic equation of state (EoS) is very familiar
to the reservoir engineering community. In contrast, in
years past, the asphaltenes were viewed as complex,
enigmatic and without a thermodynamic foundation.
Consequently, oil􀂿 eld observations related to asphaltenes,
such as asphaltene gradients in crude oil, heavy-oil
gradients, viscosity gradients, tar mat formation, bitumen
deposition and asphaltene 􀃀 ow assurance, were all viewed
very much within a phenomenological context without
a 􀂿 rst-principles foundation. In the recent past, a simple
molecular and nanocolloidal model of asphaltenes, the
Yen-Mullins model, has been shown to apply broadly. This
model, combined with the Flory-Huggins-Zuo Equation
of State (FHZ EoS), accounts for asphaltene gradients
in bulk oil and when combined with the Langmuir EoS
accounts for oil-water interfacial properties. Such success
establishes validation.
These new developments in asphaltene science
have been closely linked with downhole 􀃀 uid analysis
(DFA) to address a wide variety of reservoir concerns.
Consequently, petrophysicists and other geoscientists
traditionally charged with the responsibility of formation
evaluation are left with the task of understanding the
asphaltenes. Here, we provide an overview of asphaltenes
in order to make asphaltenes accessible to technologists
who are not expert in petroleum and asphaltene science.
The emphasis is on the simplicity of asphaltene chemistry.
This discussion naturally leads to basic chemical precepts
of solubility especially because asphaltenes are de􀂿 ned by
their solubility characteristics.

- by Oliver C Mullins and +1
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- Geochemistry, Reservoir Engineering, Oil and gas, Reservoir Characterization

- by Omar Elkadi and +2
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- Civil Engineering, Construction Technology, Geotechnical Engineering, Flexible Pavement Design
- by Lizette Olid
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- Asphalt Pavements

En este texto se involucra un análisis de la mecánica de pavimentos con un componente altamente numérico y práctico al mismo tiempo. Se maneja la teoría de la elasticidad (métodos racionales) y leyes de fatiga para los materiales que conforman las capas de los pavimentos, para el cálculo de esfuerzos y deformaciones producidos por las cargas reales de los vehículos, balanceando las admisibilidades reales de las estructuras de pavimentos. En el libro se tratan conceptos de materiales, teoría de asfaltos, métodos constructivos de pavimentos asfálticos y de concretos, diseños de estructuras -bituminosas, mixtas, inversas de concreto- y cálculo de recalzas, además de que se introduce al empleo de los elementos finitos y al análisis del fenómeno del bombeo en pavimentos rígidos.

The aim herein was to equip civil engineers and students with an advanced pavement modeling tool that is both easy to use and highly adaptive. To achieve this, a mathematical solution for a layered viscoelastic half-space subjected to a moving load was developed and subsequently implemented in a spreadsheet environment. The final program can consider up to five fully bonded layers, each isotropic, homogeneous and weightless. The top layer (as well as others if desired) is linear viscoelastic, while the remaining layers are linear elastic. The load is applied vertically to the surface of the system, uniformly spread over a circle, and moving with constant speed along a straight line. The final workbook, named ELLVA1, offers a near real-time solution for the history of stress, strain, and displacement inside the system at any point of interest resulting from a single pass. Despite built-in formulation approximations and limitations of operating under a spreadsheet environment, computation results are shown to be almost exact.