Hard Asphalt Research Articles

High-Temperature Rheology Characteristics of Hard Petroleum Asphalt Used in China

Hard petroleum asphalt, which is a high modulus asphalt binder material, is used for improving asphalt pavement rutting distress. This property is attributed to the good high-temperature rheological characteristics of hard petroleum asphalt. The study investigates the performance of hard petroleum asphalt and Styrene-Butadiene-Styrene polymer modified asphalt (SBSPMA) based on three aspects: asphalt oil source, asphalt grade, and aging degree. The short-term and long-term aging of four hard petroleum asphalts and SBSPMA of comparative samples were measured using the rolling thin film oven test (RTFOT) and the pressure aging test (PAV). Firstly, the viscosity-temperature curve of hard petroleum asphalt was obtained using the Brookfield viscosity test at different temperatures combined with the improved REFUTAS formula. The complex shear modulus ( G ∗ ), phase angle (δ), and rutting factor ( G ∗ / sin δ ) of each asphalt sample were then measured by the dynamic shear rheometer test (DSR). Furthermore, the temperature sensitivity of each asphalt sample was calculated using the complex modulus index method (GTS). The compaction and paving temperature ranges of each asphalt were then confirmed. The results showed that the high-temperature rheological characteristics of hard petroleum asphalt were similar to those of SBSPMA. The temperature sensitivity of hard petroleum asphalt was basically the same as that of SBSPMA, while the influence of aging on the G ∗ of hard petroleum asphalt was greater than that of SBSPMA. In addition, the hard petroleum asphalt construction temperature was lower than that of SBSPMA.

Development of Cost-Effective High-Modulus Asphalt Concrete Mixtures Using Crumb Rubber and Local Construction Materials in Louisiana

One of the emerging solutions to enhance the durability of asphalt pavements is the use of a French asphalt mix known as “High-Modulus Asphalt Concrete (HMAC).” This mix uses a hard asphalt binder, high binder content (about 6%), and low air voids content as compared with Superpave mixtures. The key objective of this study was to develop a cost-effective HMAC mixture using crumb rubber and local materials in Louisiana. To achieve this objective, four HMAC mixtures were prepared using two asphalt binders (PG 82-22 and PG 76-22 plus 10% crumb rubber) and two Reclaimed Asphalt Pavement (RAP) contents (20% and 40%); additionally, a conventional Superpave mixture in Louisiana was prepared as a control mixture. The laboratory performance of these five mixtures was evaluated in relation to workability, dynamic modulus, rutting resistance, and cracking resistance. The AASHTOWare Pavement ME Design software was also used to estimate the long-term field performance of these mixtures. Results indicated that the HMAC mixture prepared with 10% crumb rubber and 20% RAP successfully met the French mix design specifications for HMAC and LaDOTD specifications. This HMAC mix outperformed the control Superpave mix in relation to dynamic modulus, rutting resistance, and cracking resistance. Additionally, this HMAC mixture can reduce the required asphalt thickness by 1.5 or 2 in. based on traffic level. The cost-effectiveness analysis indicated that this HMAC mixture was more cost-effective than conventional Superpave mixtures in Louisiana. In addition, this mixture is environmentally friendly as it can reduce the disposal of scrap tires in landfills.

Influence of Waste Cork with Thinner on the Rheological Properties of Asphalt

Over the last two decades, the rapid and continued deterioration of the transportation network has been regarded as a major issue. There are many measures that can be taken to reduce this deterioration and improve road specifications, including improving road design, using higher quality materials, and using more efficient construction methods. This study is concerned with three principles: including investigating the impact of using waste paste on the rheological properties of bitumen; the environmental pollution that is a global problem; and the economic benefits as a result of the reusing of waste materials such as corks to produce new reusable materials like Modified-Asphalt. In this research, cork has been melted by thinner and mixed with asphalt to get a good paste with weight percentages of 1%, 3%, 5%, and 7%. After conducting the necessary tests on the samples, it was found that the addition of waste paste to virgin bitumen has softened the bitumen by decreasing the hardness and adhesiveness of the bitumen by increasing penetration with increasing cork paste content. The findings show that the current procedure can be used in cold regions because it requires less hard asphalt than that used in hot regions. It can also be used with natural asphalt, like natural rock asphalt, in various percent to give asphalt with suitable properties for use in roofing and paving roads.

Recycling Aged Asphalt Using Hard Asphalt Binder for Hot-Mixing Recycled Asphalt Mixture

Increasing the content of reclaimed asphalt pavement material (RAP) in hot-mix recycled asphalt mixture (RHMA) with a satisfactory performance has been a hot topic in recent years. In this study, the performances of Trinidad lake asphalt (TLA), virgin asphalt binder, and aged asphalt binder were first compared, and then the modification mechanism of TLA on virgin asphalt and aged asphalt was explored. Furthermore, the RHMA was designed in accordance with the French norm NF P 98-140 containing 50% and 100% RAP, and their high-temperature stability, low-temperature cracking resistance, and fatigue performances were tested to be compared with the conventional dense gradation AC-20 asphalt mixture. The results show that the addition of TLA changes the component proportion of virgin asphalt binder, but no new functional groups are produced. The hard asphalt binder modified by TLA has a better rutting resistance, while the fatigue and cracking resistance is lower, compared to both aged and virgin asphalt. The high-modulus design concept of RHMA is a promising way to increase the RAP content in RHMA with acceptable performance. Generally, the RHMA with 50% RAP has similar properties to AC-20. And, when the RAP content reaches 100%, the high- and low-temperature performance and anti-fatigue performance of RHMA are better than AC-20 mixture. Thus, recycling aged asphalt using hard asphalt binder for hot-mixing recycled asphalt mixture to increase the RAP content is feasible.

Assessing Mechanical Properties of Hard Asphalt Mixtures with Different Design Methods

AbstractMarginal hard asphalt possesses high stiffness and modulus; however, due to poor ductility at low temperature, it was seldom applied into road structures. Increasing asphalt content seemed ...

Determination of volumetric criteria for designing hard asphalt mixture

The current mix design method that is established based on the volumetric properties works well for conventional hot-mixed asphalt (HMA), but does not satisfy the design of hard HMAs. Hard HMAs refer to the mixtures designed using hard asphalt binder whose penetration is less than the conventional one (70#). Increasing asphalt content is regarded to be an effective way to design hard HMAs and keeps them away from thermal cracking problem. Therefore, this research explored the suitable volumetric criteria for designing hard HMAs. The principle of establishing the volumetric criteria is to ensure hard HMAs can achieve the equivalent performance as conventional ones. Eleven groups of AC16 containing three penetration grades of asphalt binders (70#, 50#, and 30#) were designed, and the volumetric properties, uniaxial penetration shear test (UPST), low-temperature bending test (LTBT) and four-point bending test (4PBT) were then conducted. Based on experiment data, two key volumetric criteria of AFT and VMA are established for hard HMAs. It can be seen that when the ranges of AFT maintain within the 10–11.2 µm and 12.9–13.4 µm, respectively, the 50# and 30# hard HMAs can reach the equivalent high- and low- temperature performance as 70# conventional HMAs. Correspondingly, the ranges of criteria in VMA for 50# and 30# hard HMAs need to maintain within 15.6–17.5% and 17.6–19.5%, respectively. Overall, a higher value of volumetric criteria is required for designing hard HMA compared with conventional one. In addition, the results of 4PBT indicate that hard HMAs can also exhibit good fatigue resistance when they are designed within these criteria.

PEMANFAATAN PASIR BESI DAN ABU SEKAM PADI PADA CAMPURAN LASTON AC-BC

Laston AC-BC is one type of flexible pavement with a mixture of hard asphalt and well graded aggregate which is spread and compacted in a hot state at a certain temperature. The type of aggregate used consists of coarse aggregate, fine aggregate and filler, with asphalt as a binder. In order to utilize local materials, Sukabumi Regency has sufficient availability of other aggregate materials to be used in the manufacture of ac-bc laston mixtures, one of which is iron sand fine aggregate which has a fairly high silica content. The availability of iron sand is quite a lot, it is necessary to do research on the use of iron sand as fine aggregate and rice husk ash as a filler in ac-bc laston. And the research used an experimental method with the asphalt content used at 6% and then examined the Marshall characteristics. The results of this study indicate that the mixture of Laston AC-BC iron sand + rice husk ash is better than the normal Laston AC-BC, the quality of the material also greatly influences the increase in stability and flow on the performance of the road pavement.

Asphalt Mixture Proportion Design Method of Coarse Graded High-Modulus Asphalt Concrete with Skeleton-Embedded Structure

In view of heavy traffic situation of asphalt pavement and the project needs in China, a kind of mixdesign method of coarse graded high modulus asphalt concrete(HMAC25)with skeleton embedded structurewas proposed. A kind of low labeled hard asphalt with penetration degree of 30(0.1 mm)(AH-30)wasused as the cementing material of high modulus asphalt concrete, and the nominal maximum aggregate size isno smaller than 26.5 mm. The asphalt-aggregate ratio of the asphalt mixture was determined by using thedesign method of asphalt mixture based on aggregate closest compact condition. The result of laboratory testindicates that(1)compared with the required value in the related specification, the high temperaturestability of high modulus asphalt concrete made with the proposed method improved by more than 7 times; (2)compared with the maximum value recommended in the related specification, the compression resilientmodulus at 20℃ increased by nearly 30%;(3)the low temperature anti-cracking performance and moisturestability can also meet the requirements of the specification.

Effects of crude oil on the performances of hard asphalt and its mixtures

ABSTRACT The quality and performance of petroleum asphalt are determined by crude oil and the production process. The pavement performance using petroleum asphalt is consequently affected by crude oil and the production process. This study investigated the effects of three types of crude oil, namely BSK, MB, and MR, on the performance of hard asphalt and corresponding asphalt mixtures. Accordingly, Pen40/60 asphalts were fabricated using the distillation process, while Pen20/40 asphalts were produced using a combination of distillation and oxidation processes. The asphalt properties were then evaluated. Moreover, the relationships between the asphalt and crude oil performances were established. The test results validated the consistency of the effects of crude oil on the asphalt performance. A certain correlation was determined between the indices of crude oil and asphalt. Furthermore, crude oil was found to greatly influence the fatigue performance. Among the three types of crude oil, the BSK crude oil product of hard asphalt exhibited good rut resistance, fatigue performance, and water stability, depicting the best performance.

Super hard asphalt (SHA) from direct coal liquefaction process as pavement material

Super hard asphalt (SHA) as a black and solid material at ambient temperature is a byproduct of direct coal liquefaction process, which mainly generates clean liquid fuels from coal and is one of the clean-coal technologies. Firstly this paper introduced how the SHA is produced, its physical properties, chemical compositions, as well as its influence to the environment. Then, the opportunities and challenges of using SHA as pavement material were discussed, including three challenges and three corresponding technologies. Lastly, the progresses for SHA based asphalts were illustrated, in which two asphalt modifiers (SHA-N and SHA-S) were produced from SHA using in-situ micro crosslink technology. Then two SHA-based modified asphalts were manufactured at an industrial scale. The performance grades were classified as PG 82–22, which present excellent high and low temperature performance. Thereafter one 1.2 km test road was paved by the road pavement asphalt using the SHA-N-based modified asphalt under AC-13C gradation as the top layer of G110 national highway in Yinchuan. The other 0.9 km test road was paved using the SHA-S modified asphalt under AC-20 gradation in the middle layer of G69 expressway in Chongqing. The field data shows that the performance of asphalt mixtures and pavements after paving is excellent. The long-term performance of the test roads will be followed.

Performance-based design of hard asphalt mixtures based on different compaction effort variable

Due to potential thermal cracking risks, marginal hard asphalt has not been widely used in China. A design method for hard asphalt under lower compaction levels was adopted in the present study with the aim of compensating for low-temperature cracking problems by increasing the asphalt content; simultaneously, the rutting resistance can still be maintained due to the high stiffness of hard asphalt itself. Four groups of asphalt, i.e. a control group (70# asphalt under Ndes = 75); two experimental groups (30# and 50# asphalt under Ndes = 50); and an analysis group (70# asphalt under Ndes = 50), were designed to evaluate the performance. Based on the experimental results, the conventional and this design method using 50# hard asphalt showed almost the same high- and low-temperature resistance. It is noteworthy that this method exhibited better fatigue resistance and increased fatigue life by approximately 1.6 times. In addition, this method also showed a larger dynamic modulus, especially under the traffic conditions of low frequency or high temperature. These results may indicate that a cheap marginal hard asphalt mixture under less compaction energy could achieve an even better performance than the conventional asphalt.

Study on Normative Standards of Hard Asphalt for highway engineering in China

Hard asphalt has been applied and studied on Chinese highway asphalt pavement for nearly 20 years. Although it has excellent road performance, it has not been applied on a large scale. The main reason is that there is no clear technical standard and technical system for hard asphalt, which restricts the popularization and application of hard asphalt as a good material in the highway engineering. Therefore, it is urgent to formulate standards for hard asphalt products of highway engineering in China. In order to promote the large-scale application of hard asphalt for asphalt pavement in China, a draft definition of hard asphalt for highway use and a draft technical standard for engineering are proposed through a large number of tests and research analysis of various samples, drawing lessons from the current technical specifications and relevant international standards for hard asphalt.

Effect of blending protocol on the performance of SBS/sulfur/soybean-derived additive composite modified hard asphalt

ABSTRACT This paper explores the feasibility of using SBS/sulfur/soybean-additive in combination in a hard asphalt binder to produce a composite modified asphalt binder. The modification effects of the additives and the influence of different blending protocols were comprehensively studied through laboratory investigations. The rheology of the asphalt binders was evaluated via viscosity, bitumen grading, master curve, Black diagram, isochronal plot, Han diagram, fatigue, creep stiffness and m-value using a bending beam rheometer (BBR), and Multiple Stress Recovery (MSCR) test using a Dynamic Shear Rheometer (DSR). The modified binder’s susceptibility to aging effects and thermal stability were also determined by calculation of the aging index (AI) and degree of separation. The results showed that the additives were able to enhance the overall performance of the hard neat Vacuum Tower Bottoms (VTBs) binder by increasing its resistance to rutting, fatigue cracking, and thermal cracking. It was also found that the additives reduced the aging susceptibility of the VTBs binder without any thermal stability or degradation issues after aging conditions. According to the overall performance of the modified binders, a blending protocol for producing a composite modified binder with optimal performance achieved through a well–developed cross-linked polymer elastic network was recommended.

High modulus asphalt concrete: A state-of-the-art review

High modulus asphalt concrete (HMAC) was originally developed in France on the base course to resist the plastic deformation with the increasing heavy traffic. Although these mixtures were designed to serve as either base courses or binder courses, they were later extended to the wearing courses. This article first reviews the components of the high modulus mixture, its detailed design process and the pavement performances, including water stability, high temperature performance, and fatigue resistance and low temperature cracking resistance. The review finds that HMAC can be produced with binders from conventional hard grade binder, natural asphalt and plastic particles and low quality aggregates can be used with incorporation of modifiers. HMAC generally have improved water stability, better rutting resistance, reasonably well fatigue resistances but questionable thermal cracking resistance. Its application in the pavement structure can reduce the pavement layer thickness and thus save construction costs. The long term performance of HMAC needs further monitoring, especially for cold regions.

KAJIAN BAHAN TAMBAH ATERNATIF SERAT ECENG GONDOK TERHADAP CAMPURAN LATASIR SAND SHEET KELAS A SPESIFIKASI SEKSI-6 2010 BINA MARGA

Asphalt sand layer (Latasir) is a layer of road construction consisting of coarse aggregates, fine aggregates, fillers and hard asphalt, which are mixed, spread, and compacted in hot conditions at certain temperatures. In this study is the use of water hyacinth fiber in a mixture of thin layer sand sheet sand grade grade A. The purpose of this study was to determine the process of making test specimens with ingredients added to water hyacinth fiber and the process of testing specimens with ingredients added to water hyacinth fiber. The test was carried out by adding water hyacinth fibers in the sand sheet class A latasir mixture. And with the addition of water hyacinth fiber variations of 0.6%, 0.9%, 1.2% taken from asphalt content. The final result of this research was Marshall evaluation which was obtained for the effect of the addition of water hyacinth cellulose fiber in this study showed an increase in Marshall stability value of 27.29% with a mixture of 1.2% water hyacinth, plastic fatigue (Flow) decreased by -23 , 89% with a mixture of 0.9% water hyacinth, cavity filled in the mixture (Void in the Mix) increased by 18.65% with a mixture of 1.2% water hyacinth, cavity filled with asphalt (Void Filled With Asphalt) decreased by -8.74% with a mixture of 1.2% water hyacinth, cavity in aggregate (Void In Mineral Aggregate) increased by 7.80% with a mixture of 1.2% water hyacinth, and Marshall Quotient increased by 71.78% with a mixture of 0.9% water hyacinth. These results indicate that water hyacinth fiber can be used as an ingredient to add a mixture of latasir sand sheet class A specifications of clan development. Keywords: sand sheet class A sandflies, Marshall Test Index, water hyacinth fiber, stability, flow, Marshall Quotient.

Performance evaluation and field application of hard asphalt concrete under heavy traffic conditions

In order to improve the service performance of asphalt pavement under high temperature and rain during summer under heavy traffic conditions, this research compared the pavement performance of hard, heavy-duty AH-70, and Styrene Butadiene Styrene (SBS) polymer-modified asphalt mixtures through high temperature performance, low temperature crack resistance, fatigue resistance, and water stability tests. Results indicate that 30# hard asphalt mixture remarkably improves high temperature performance compared with 70# and 70# SBS asphalt mixtures. Moreover, the water stability of these asphalt mixtures is comparable. The fatigue performance of 30# hard asphalt mixture is comparable with that of 70# asphalt mixture. Finally, after 10 years of pavement performance, the hard asphalt concrete pavement structure achieved the best road conditions.

Study on the warm-recycled mechanism of SMA and the road performance

In order to evaluate the performance of warm-recycled asphalt mixture with SMA, based on analyzing the characteristics of gradation, aggregate and aging asphalt with reclaimed asphalt pavement (RAP), The regeneration methods of high grade soft asphalt mixed at low temperature and hard natural asphalt remixed with modification to enhance are proposed, and it was used to prepare recycled asphalt mixture with SMA and different RAP contents(0, 10%, 20%, 30%). And its high temperature performance, water stability, low temperature performance and fatigue performance were comprehensively evaluated. The result showed that soft and rock compound regeneration technology is feasibility, the natural asphalt with strong polar functional groups was modified and strengthened by remixing to improve the comprehensive performance of asphalt; the performance of warm mix recycled mixture with the 7:3 ratio of 110 # asphalt matrix and TLA lake asphalt is better; the best dosage of RAP is 20%; compared with HMA and SBS modified asphalt mixture, temperature can reduce 15°C and 30°C to 35°C respectively.

Жоңғыш кескiштердi қатты қыртыстарды және асфальтбетонды жол жабындыларын сындыру үшiн гидравликалық экскаватордың қосымша жұмыс органы ретiнде пайдалану

Жоңғыш кескiштердi қатты қыртыстарды және асфальтбетонды жол жабындыларын сындыру үшiн гидравликалық экскаватордың қосымша жұмыс органы ретiнде пайдалану

Performance Evaluation of Conventional and High Modulus Asphalt Concrete with Novolac Polymer Modifier Using Aashtoware Software

In order to changes the original asphalt characteristics, there are many additives have been used to produce or modify the High Modulus Asphalt Binder (HMAB). Even though the hard grade asphalt binder has some disadvantages, such as the aging process due to high mixing and compacting temperature, which can negatively affect the pavement performance, some other advantages include increasing stiffness modulus of asphalt binder and high resistance to permanent deformation. Also, using the hard grade asphalt binder will save construction costs by reducing the asphalt pavement thickness due to its high stiffness modulus. In Iraq, the Novolac modifier and its Cross-linking Agent (Hexamine) was used for the first time as a modifier for asphalt which can significantly improve the rheological properties of asphalt and its role in HMA. This study focuses on estimating the thickness reduction of flexible pavement due to using High Modulus Asphalt Concrete (HMAC). The reduction in permanent deformation and thickness of pavement were estimated for suggested pavement structure sections implemented HMAC mixture compared with the pavement section implemented conventional mixtures using AASHTOWare software version 2.3. The analytical results indicate that adding 4% of Novolac modifier and 15 % of Hexamine (form weigth of Novolac) is reduced the permanent deformation and bottom up cracking by 30% and 46 % compared to conventional mix, respectively. However, it can be concluded that adding Novolac polymer modifier enhanced the pavement performance.

The use of compressible packing model and modified asphalt binders in high-modulus asphalt mix design

High-modulus asphalt mix, Enrobé à Module Élevé (EME) in French, is a type of HMA representing high modulus or stiffness. Traditionally, EME mixes are fabricated with straight-run hard grade asphalt cement which has poor performance at lower temperatures and is very susceptible to low-temperature cracking in cold regions. The main objective of this study is therefore developing a new approach to EME mix design that contributes to good performance at high, medium and low temperatures. EME mixes have a dense structure. In this regard, Compressible Packing Model (CPM) was used to optimise the packing degree of EME mixes for two different mix types based on nominal maximum aggregate size (EME 12.5 and EME 19). In addition, three types of modified asphalt binders, namely: PG 88-28, PG 82-28 and PG 58-28 plus 10% Elastomer additives were used in this study. Thermo-mechanical tests were conducted to evaluate the performance of EME mixes in terms of stiffness, rutting, fatigue and low-temperature cracking. Obtained results showed that the developed mixes had acceptable performance at all levels, and that the mixes could satisfactorily perform at lower temperatures.