The effect of nanoclay as bitumen modifier on rutting performance of asphalt mixtures containing high content of rejuvenated reclaimed asphalt pavement

Using some kinds of rejuvenators to restore the characteristics of aged binder in reclaimed asphalt pavement might lead to reduction in rutting resistance. In this research, nanocaly was used as virgin bitumen modifier to compensate for the negative effect of rejuvenator in asphalt mixtures containing high percentages of reclaimed asphalt pavement. For this purpose, dynamic creep test was conducted on the mixtures containing 2%, 4% and 6% modified NC and 25%, 50%, 75% RAP. Laboratory test results indicated that the reduction of flow number due to adding rejuvenator in the mixture can be compensated by using nanoclay modified virgin bitumen.     

The effect of bitumen types on the performance of high-modulus asphalt mixtures

The objective of this study was the evaluation of high-modulus asphalt mixtures (HMAM). Two types of hard-penetration bitumen (HPB) and conventional bitumen were used to fabricate Enrobés à Module Elevé Class 2 (EME2) and Grave Bitumen Class 5 (GB5)) and control mixtures, respectively. In this study, complex modulus, fatigue, dynamic creep and moisture sensitivity tests and also, Witczak and Zhou models were used to evaluate the performance of the prepared mixtures. Results showed that hard-penetration bitumen (HPB) improved the performance of asphalt mixtures compared to conventional bitumen.     

The influence of nanoclay on the performance properties and moisture susceptibility of rubberized asphalt mixture

The authors investigated the effect of nanoclay (NC) on the performance properties and moisture susceptibility of rubberized asphalt mixtures. Two percent crumb rubber modifier (CRM) and NC in both combined and separate modes and the effects of each additive on bitumen performance were examined through administering tests of penetration grade, softening point and temperature susceptibility. Also, indirect tensile strength tests in both dry and saturated states were performed to allow for measuring the moisture susceptibility of asphalt mixtures. Moreover, the effect size of both additives on improving the bitumen performance and asphalt mixtures was assessed by running analysis of variance method and sensitivity analysis. The results of the laboratory test and statistical analyses revealed that CRM and NC improved the properties of bitumen and asphalt mixtures. This improvement was associated with the content and type of the additives applied, and also bitumen and asphalt mixtures had the best performance in presence of a combination of CRM and NC.     

Effect of different rejuvenators on the properties of aged SBS modified asphalt

The styrene-butadiene-styrene copolymer (SBS)–modified asphalt was aged by pressure aging vessel test. The effect of different content of rejuvenators on the physical and rheological properties of aged SBS-modified asphalt was investigated. The results showed that with the increase of the content, the physical and rheological properties of the aged SBS-modified asphalt are restored more significantly. Three kinds of rejuvenators were used to rejuvenate the properties of aged SBS-modified asphalt. It can be concluded that the improvement of rejuvenator-III on the properties of aged SBS-modified asphalt is the most obvious. The results also indicate that the rheological behavior of the aged SBS-modified asphalt is improved obviously by the rejuvenator.     

The effect of nano-SiO2 and the styrene butadiene styrene polymer on the high-temperature performance of hot mix asphalt

The production of modified asphalt mixtures with appropriate performance in high temperature has always been under the attention of researchers. One of these modifiers is Styrene Butadiene Styrene (SBS) polymer. Since the application of SBS polymer in bitumen and asphalt mixture does not have expected performance of field due to phase separation of bitumen and polymer, oxidation, and aging, the present study tries to not only improve the polymer defects, but also analyzes its high-temperature performance by using nano-SiO₂ and SBS polymer in bitumen modification. According to the study results, adding nano-SiO₂ and SBS polymer with 3 and 4.5 bitumen weight percent, respectively, to bitumen in asphalt mixture leads to an increase of flow number in dynamic creep test at 50°C for 399 times and at 60°C for 1,015 times compared to unmodified asphalt mix. This, in turn, indicates the considerable improvement of asphalt mixture high-temperature performance.     

不同粘度等级的再生剂对老化沥青再生性能的影响

研究了不同粘度等级的再生剂对老化沥青再生性能的影响。结果表明,不同粘度等级的再生剂对老化沥青的再生效果有明显差异。粘度低的再生剂对老化沥青软化点的降低、延度的提高、针入度的增大和粘度的减小更为明显。然而,对于轻度老化沥青,低粘度再生剂使其软化点和粘度降低幅度较大,对再生沥青的高温性能影响明显,因此轻度老化沥青宜选用粘度较高的再生剂,而重度老化沥青应选用低粘度的再生剂。     

Investigating the influence of using nano-composites on storage stability of modified bitumen and moisture damage of HMA

In this study, a composite of styrene butadiene rubber (SBR) and nano-clay was made with different ratios and used for bitumen modification. The results show that using nano-composites improves storage stability at high temperature. However, pure SBR modified bitumen is proved not to be stable at high temperature. Investigating the results of indirect tensile strength and indirect tensile strength ratio also indicates that nano-composites improve moisture sensitivity of hot mix asphalt (HMA). Further, according to the results, increasing the content of nano-clay enhances the resistant of asphalt mixtures against moisture damage.     

Influence of Fly Ash on the Properties of Asphalt

Abstract

In this study, we investigated fly ash replacement of the fine aggregate in hot-mix asphalt concrete mixtures. Fly ash was obtained from the Soma thermal power plant. Fly ash in amounts of 5, 6, 7, and 8% by total aggregate weight was added as an additive to asphalt concrete mixtures. Mixtures were prepared without additives containing filler, which had the same percentages as the fly ash mixtures, and briquette samples were prepared from mixtures with fly ash and with filler. Marshall tests were applied to the samples, and optimum asphalt contents were determined. In the optimum conditions, parameters were determined, which were stability, practical specific gravity, void, flow, and max theoretical specific gravity. The results indicate that the stability values obtained from mixtures with fly ash are higher than mixtures from filler. The highest stability value was obtained from 5% fly ash added mixture, which was 1,630 kg in optimal conditions.     

废食用油用于沥青再生的应用前景分析

我国废食用油已成为环境污染物,并冲击食品安全,如近年来地沟油事件频发,严重危害着人们身心健康。废食用油中含有大量不饱和脂肪酸,类似于沥青中的油分,而沥青老化后其油分会减少。根据沥青再生理论与相关研究,废食用油可作为低粘度油分用于沥青再生,有望通过以废治废的方式,实现废食用油与废旧沥青路面材料的同时利用,有利于环境保护,具有广阔的应用前景。为了实现废食用油在沥青再生领域的应用,应该重点开展废食用油的分类与处理技术、废食用油对老化沥青的再生效果、再生机理以及应用技术等方面的研究。     

A HIGH PRESSURE METHOD OF BITUMEN EXTRACTION FROM ASPHALT PAVEMENT

ABSTRACT

A new. less costly method of extracting bitumen from asphalt pavament mixtures has been developed which gives bitumen contents essentially the same as those obtained by the currently used centrifuge method. The preferred solvent is cyclohexane (although cyclopentane may be used) at high temperatures and pressures. The new method uses these non-chlorinated solvents at high temperatures and pressures (but sub-critical) to dissolve and extract asphalt from the mix in a stainless steel extractor vessel. Although these solvents are less hazardous to the health of the laboratory personnel than chlorinated solvents, they can be a fire hazard unless reasonable precautions are exercised     

不同掺量岩沥青改性沥青混合料性能试验研究

利用天然岩沥青作改性剂,对AH-70基质沥青进行改性,采用AC-13型沥青混合料进行配合比设计,分别对0、5％、7．5％、10％掺量的岩沥青改性沥青混合料的动态模量进行试验研究,结果表明在一定温度控制下,掺加不同剂量的岩沥青改性剂,对沥青混合料动态模量均有较大的改善。在相同温度和频率下,随着岩沥青掺量的增加,动态模量逐渐增大,当岩沥青掺量达5％时,混合料动态模量满足法国高模量沥青混凝土的标准。     

STUDY ON THE PREPARATION OF ASPHALT WITH SPECIAL USES FROM CHINESE TAR SANDS

ABSTRACT

Tar sand heavy oil ( TSHO ) was extracted from Xinjiang Xiaoxigou and Fengcheng tar sands. The basic properties of the TSHO were investigated. It is found that the TSHOs are not suitable to produce paving asphalt. However, some asphalt products with special uses were prepared from the TSHOs. The results show that Xiaoxigou TSHO can be used to produce anticorrosion asphalt for pipeline. Fengcheng TSHO, blended with kramai vacuum residuum and Gudao vacuum residuum, can be used to produce painting and polishing asphalt. The influence of the blending asphalt's SARA compositions on their qualities was also investigated.     

Evaluating the rheological effect of asphalt binder modification using soybean oil

Brazil is a highlight in the ranking of maize cooking oil production, which after consumption generates a significant amount of waste that the improper disposal of it, which could seriously affect the sewage pipes, groundwater, and soil. This research study the incorporation of 1%, 2%, and 3% of soybean (new and waste) in asphalt binder. The samples were analyzed by FTIR and frequency sweep tests. The results indicate that the optimum oil content is in the range of 1–2%, regardless of being new or residual. In the temperature sweep, it was found that the asphalt binder 55/75-E showed a smaller phase angle in all mixtures compared to the asphalt binder 50/70, thus having a better elastic recovery.     

The Evaluation of Oil Sand Bitumen Produced From Inner Mongolia

On the basis of an analysis, the bitumen produced from Inner Mongolia oil sand belongs to a kind of sour naphthenic based oil with the properties of high density (ρ₂₀ = 0. 9996 g·cm^?3), high viscosity (υ₁₀₀ = 1553/(mm²·sec^?1)), rich resin, and asphalt. After a series of fractions is cut by true boiling distillation (TBP) SBD-β instrument and analyzed by corresponding instruments, the processing scheme of tar sand bitumen is proposed. The initial boiling point is 281°C, and the yield of diesel, lube oil, and residual oil is 4.54%, 16.73%, and 38.06%, respectively.     

塔河稠油沥青改性及应用研究

介绍了以塔河稠油沥青为原料的SBR改性、SBS改性沥青工艺，重点阐述了根据路面应用要求设计生产的改性沥青性能，选定AC-13级配进行混合料性能研究，表明塔河稠油SBR改性沥青和SBS改性沥青路用性能优良，满足高等级公路建设要求。     

Adhesion of Recycled Concrete Aggregates,Demolition Debris,and Asphalt

In this investigation, rolling bottle tests and boiling water tests were conducted to evaluate the effect of different fillers and treatments on the adhesion between recycled concrete aggregates (RCA) and asphalt. The test results when 100% RCA loose mixtures were evaluated indicated that the filler that achieves the best asphalt aggregate bond was grey Portland cement. Curing the mixture in an oven for 4 h at mix temperature before compacting and coating RCA with bitumen emulsion are treatments that achieved satisfactory adhesion results as well.     

The rheological behavior of bitumen and moisture susceptibility modified with SBS and nanoclay

The effect of styrene–butadiene–styrene (SBS) and nanoclay additive on performance of pure bitumen and stone matrix asphalt (SMA) mixture was investigated. Different samples with various percentages of nanoclay (2%, 3%, 4%, and 5%) and SBS (0% and 5%) by weight of bitumen were prepared, and the rheological and chemical behavior of bitumen (rotational viscosity, dynamic shear rheometer, SEM, and FTIR), the indirect tensile strength and moisture susceptibility of different mixtures were evaluated. Based on the results, using nanoclay and SBS polymer can improve the rheological behavior of base binder and the resistance of SMA mixtures against moisture damage.     

Moisture susceptibility of warm mixed-reclaimed asphalt pavement containing Sasobit and Zycotherm additives

In this research, the influence of Sasobit and Zycotherm on the properties of reclaimed asphalt pavement (RAP)-warm mix asphalt (WMA) was investigated. Moisture susceptibility was evaluated applying the resilient modulus ratio, the indirect tensile strength ratio, and the fracture energy ratio. Laboratory testing results indicated that Zycotherm mixtures had more resistance to moisture damage than Sasobit WMA and hot mix asphalt (HMA) mixtures. The stiffness of mixtures increased dramatically by increasing the amount of RAP and using Sasobit exacerbated this problem.     

Evaluation of rutting resistance of asphalt binders and asphalt mixtures modified with polyphosphoric acid

In this research, a polyphosphoric acid (PPA) additive was used to modify a performance graded binder (PG 58-22). Experimental program included use of three PPA contents (0.5%, 1%, and 1.5%) by weight of bitumen and use of antistripping limestone aggregates. High-temperature rheological properties of asphalt binders were evaluated through the frequency sweep test. Complex modulus test was also used to evaluate rutting characteristics of asphalt mixtures. Results showed that PPA significantly improved rutting resistance of both unmodified asphalt binder and unmodified asphalt mixture, especially for the asphalt binder.     

RHEOLOGICAL PROPERTIES OF COAL OIL MIXTURES: INFLUENCE OF COAL PROPERTIES

ABSTRACT

The effect of coal properties on the rheological properties of coal oil mixtures (COM) has been studied. Coal samples having different ash and moisture contents have been used to study the effect of these components on rheological properties of coal oil mixtures. It has been observed that coals having higher ash content give rise to less viscous coal oil mixtures and viscosity of the COM decreases as moisture content of coal is reduced.