scholarly journals Volumetric characteristics and compactability of asphalt rubber mixtures with organic warm mix asphalt additives

2017 ◽  
Vol 67 (327) ◽  
pp. 123 ◽  
Author(s):  
A. M. Rodríguez-Alloza ◽  
J. Gallego
Keyword(s):  
Energy Consumption ◽  
Lower Energy ◽  
Laboratory Tests ◽  
Waste Product ◽  
Road Construction ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Organic Additives ◽  
Asphalt Rubber ◽  
Volumetric Characteristics

Warm Mix Asphalt (WMA) refers to technologies that reduce manufacturing and compaction temperatures of asphalt mixtures allowing lower energy consumption and reducing greenhouse gas emissions from asphalt plants. These benefits, combined with the effective reuse of a solid waste product, make asphalt rubber (AR) mixtures with WMA additives an excellent environmentally-friendly material for road construction. The effect of WMA additives on rubberized mixtures has not yet been established in detail and the lower mixing/compaction temperatures of these mixtures may result in insufficient compaction. In this sense, the present study uses a series of laboratory tests to evaluate the volumetric characteristics and compactability of AR mixtures with organic additives when production/compaction temperatures are decreased. The results of this study indicate that the additives selected can decrease the mixing/compaction temperatures without compromising the volumetric characteristics and compactability.

scholarly journals Effects of Selected Warm Mix Asphalt Additives on Viscosity Properties of Binder

2018 ◽  
Vol 1 (1) ◽  
pp. 80-84
Author(s):  
Bekir Aktas ◽  
Şuayıp Aytekin ◽  
Şevket Aslan
Keyword(s):  
Energy Consumption ◽  
Lower Energy ◽  
Asphalt Mixture ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Energy Costs ◽  
Great Effort ◽  
Rotational Viscometer ◽  
Production Temperature ◽  
Emission Ratios

Asphalt industry has spent great effort to reduce mixing and compaction temperatures of the asphalt mixture because of increasing emission ratios and energy costs. The production of Warm Mix Asphalt (WMA) is related to attaining proper viscosity value of the binder to increase aggregate-binder bonding and compaction of the mixture at lower temperatures. The most important advantages of WMA are lower energy consumption and less pollution. Generally, the production temperature of the asphalt mixture depends on the asphalt properties. In this study, effects of selected warm mix asphalt additives of a certain amount by weight are investigated in terms of viscosity in a Brookfield Rotational Viscometer. The reducing viscosity of the binders will increase production and compaction ability of the mixtures. Also, it will allow to reduce mixing and compaction temperature. Therefore, with the decreased cooling rate asphalt mixtures can haul longer distances and give more time for site construction. The findings of this study show that under the same rotational speed viscosity decreases when additives are used.

scholarly journals Evaluation of the Potential of Sasobit REDUX Additive to Lower Warm-Mix Asphalt Production Temperature

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1285 ◽  
Author(s):  
Arminda Almeida ◽  
Michela Sergio
Keyword(s):  
Construction Industry ◽  
Road Construction ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Asphalt Production ◽  
Air Voids ◽  
Health Concerns ◽  
The Road ◽  
Wide Range ◽  
Production Temperature

Environmental and health concerns have been increasing in the road construction industry. This industry has provided several techniques and a wide range of additives to lower the production temperatures of asphalt mixtures, generating, among others, a new mix type called warm-mix asphalt (WMA). This paper aims to evaluate the potential of the Sasobit REDUX additive to lower the production temperatures of WMA. This additive, which is an alternative to the well-known Sasobit, is completely soluble in bitumen at temperatures above 85 °C while the same temperature for the Sasobit is 115 °C. For that reason, three target compaction temperatures were considered (90, 100 and 110 °C) and both Marshall and compactability tests were carried out. A hot-mix asphalt (HMA) was tested in parallel for comparison. It was concluded that the volumetric properties (air voids content about 4%) and the Marshall properties (stability about 11 kN, flow about 4 mm and Marshall quotient higher than 2 kN/km) of the Sasobit REDUX-WMA were globally satisfactory. In relation to the compactability test, the Sasobit REDUX-WMA mixtures were relatively easier to be compacted compared to the HMA mixture. The three Sasobit REDUX-WMA mixtures (90, 100 and 110 °C) exhibited a very similar compactability (differences lower than 0.4%). Therefore, it seems reasonable to conclude that the Sasobit REDUX has potential to lower WMA production temperatures by 20 °C. A reduction of that magnitude would lead to significant environmental gains.

scholarly journals Environmental Impact Assessment of Different Warm Mix Asphalts

2021 ◽  
Vol 13 (21) ◽  
pp. 11869
Author(s):  
Anda Ligia Belc ◽  
Adrian Ciutina ◽  
Raluca Buzatu ◽  
Florin Belc ◽  
Ciprian Costescu
Keyword(s):  
Environmental Impact ◽  
Hot Mix Asphalt ◽  
Raw Materials ◽  
Asphalt Mixture ◽  
Warm Mix Asphalt ◽  
Organic Additive ◽  
Asphalt Mixtures ◽  
Organic Additives ◽  
Chemical Additive ◽  
Production Phase

Within the last decade, much attention has been focused on determining viable techniques for producing sustainable asphalt mixtures and minimizing fuel use and greenhouse gas emissions. Thus, warm mix asphalt (WMA) has become a topic of significant interest among road specialists as it offers a potential solution for reducing the environmental impact of the asphalt mixtures due to the decreased temperatures they require for mixing and compaction compared to hot mix asphalt (HMA). The present study is focused on the Life Cycle Assessment (LCA), according to a “Cradle-to-Gate” approach, of hot mix asphalt and warm mix asphalt prepared with locally available materials and different warm mix additives such as organic additives, chemical additive, and synthetic zeolite. For the analysis of the environmental impact of the warm mix asphalts was used a dedicated software for modeling and evaluating the LCA. The WMA prepared with chemical additive or organic additive led to a decrease of the environmental impact, in the production phase, compared to HMA. The study reveals that the raw materials extraction has the greatest impact on the environment in all studied cases, followed by the actual production phase of the asphalt mixture. For WMA produced with additives there was a decrease in the global impact on the environment compared to HMA.

scholarly journals Building Sustainable Pavements: Investigating the Effectiveness of Recycled Tire Rubber as a Modifier in Asphalt Mixtures

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7099
Author(s):  
Christina Plati ◽  
Brad Cliatt
Keyword(s):  
Asphalt Concrete ◽  
Mechanical Characterization ◽  
Waste Product ◽  
Road Construction ◽  
Asphalt Mixtures ◽  
Social Benefits ◽  
Innovative Materials ◽  
Overall Performance ◽  
Binder Material ◽  
Compaction Degree

Building more sustainable pavements for the future requires knowledge of alternative and innovative materials for utilization in future road construction and maintenance activities. Being mindful of this need, the present study investigates a Reacted and Activated Rubber (RAR) compound modifier with the aim of defining an optimal RAR percentage in Asphalt Concrete (AC) mixes. It is acknowledged that when this type of modifier is incorporated within an AC mix as an alternative for the bituminous binder material, the associated economic, environmental and social benefits are significant. Simply put, the use of RAR modifiers provides the potential to utilize a waste product (rubber tires) as a more sustainable alternative to bitumen within AC mixtures. However, it seems that the information about the overall performance of AC mixes modified with RAR is currently limited. On these grounds, the present study focuses on the surface course layer and evaluates (a) achieved physical characteristics (compaction degree/voids), (b) mechanical characterization results (stiffness moduli) and (c) friction-based properties of tested mixtures incorporating varying RAR levels and different test temperatures. From the evaluation, it is concluded that for the case of the surface course mixture under investigation, the optimal percentage by weight of bitumen for inclusion of the RAR modifier is 10%.

scholarly journals “Warm Mix Asphalt’’ for Airport Use

2016 ◽  
Vol 5 (2) ◽  
pp. 50-60
Author(s):  
Claudia Petcu ◽  
Carmen Răcănel
Keyword(s):  
Fatigue Test ◽  
Compression Test ◽  
Laboratory Tests ◽  
Hot Mix Asphalt ◽  
Triaxial Compression ◽  
Asphalt Mixture ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Stiffness Modulus ◽  
Fuel Resistance

Abstract “Warm Mix Asphalt” (WMA) is a technology developed to obtain an asphalt mixture at lower temperatures. The method has significant benefits for the economic and environmental area. As known, “warm mix asphalt” uses additives in bitumen having the purpose to reduce the viscosity in order to decrease the mixing and compaction temperatures. Hot mix asphalt used in the airport area, especially the area of taxiway and the apron must satisfy beside usual requirements for roads, some requirements related to fuel resistance and de-icing agents according to European norms. Does warm mix asphalt for airport use meet the requirements according to European norms? This is the question from this paper which aims to determine the characteristics of asphalt mixtures for airports BBA16 when using or not using an additive, considering a series of laboratory tests: cyclic triaxial compression test, fatigue test, stiffness modulus test and resistances to fuels test.

scholarly journals Performance Evaluation of WMA Containing Re-Refined Acidic Sludge and Amorphous Poly Alpha Olefin (APAO)

2021 ◽  
Vol 13 (6) ◽  
pp. 3315
Author(s):  
Mansour Fakhri ◽  
Danial Arzjani ◽  
Pooyan Ayar ◽  
Maede Mottaghi ◽  
Nima Arzjani
Keyword(s):  
Resilient Modulus ◽  
Permanent Deformation ◽  
Road Construction ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Modified Bitumen ◽  
Alternative Source ◽  
The Road ◽  
Marshall Test ◽  
Alpha Olefin

The use of waste materials has been increasingly conceived as a sustainable alternative to conventional materials in the road construction industry, as concerns have arisen from the uncontrolled exploitation of natural resources in recent years. Re-refined acidic sludge (RAS) obtained from a waste material—acidic sludge—is an alternative source for bitumen. This study’s primary purpose is to evaluate the resistance of warm mix asphalt (WMA) mixtures containing RAS and a polymeric additive against moisture damage and rutting. The modified bitumen studied in this research is a mixture of virgin bitumen 60/70, RAS (10, 20, and 30%), and amorphous poly alpha olefin (APAO) polymer. To this end, Marshall test, moisture susceptibility tests (i.e., tensile strength ratio (TSR), residual Marshall, and Texas boiling water), resilient modulus, and rutting assessment tests (i.e., dynamic creep, Marshall quotient, and Kim) were carried out. The results showed superior values for modified mixtures compared to the control mix considering the Marshall test. Moreover, the probability of a reduction in mixes’ moisture damage was proved by moisture sensitivity tests. The results showed that modified mixtures could improve asphalt mixtures’ permanent deformation resistance and its resilience modulus. Asphalt mixtures containing 20% RAS (substitute for bitumen) showed a better performance in all the experiments among the samples tested.

scholarly journals Effects of the Geometric Parameters of Mixer on the Mixing Process of Foam Concrete Mixture and Its Energy Efficiency

2020 ◽  
Vol 10 (22) ◽  
pp. 8055
Author(s):  
Sergey A. Stel’makh ◽  
Evgenii M. Shcherban’ ◽  
Anatolii I. Shuiskii ◽  
Al’bert Yu. Prokopov ◽  
Sergey M. Madatyan ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Lower Energy ◽  
Geometric Parameters ◽  
Concrete Mixture ◽  
Mixing Process ◽  
Conical Part ◽  
Foam Concrete ◽  
Optimal Range ◽  
Optimal Values

The paper studies the influence of the geometric parameters of the mixer on the mixing process, the construction of the mixing body, its location in the mixer bulk, and the mixer shape and geometry. The technique of calculating the power spent on mixing the foam concrete mixture is described. The effects of the ratio of the mixture height to the mixer diameter, the number and width of reflective partitions, and the shape of the conical part of the mixer on the homogeneity of the foam concrete mixture and the power consumption are considered. The optimal ratios of the foam concrete mixture height to the mixer diameter have been determined. Moreover, the optimal range of the ratios of the partition width to the mixer diameter has been established, in order to obtain a homogeneous foam concrete mixture throughout the volume with lower energy consumption. The optimal values of the angle of the mixer conical part for the preparation of a foam concrete mixture have been determined.

One-pot three-step mechanically assisted synthesis and catalytic performance of tripodal metallic complexes

2021 ◽  
Author(s):  
Rima Tedjini ◽  
Raquel Viveiros ◽  
Teresa Casimiro ◽  
Vasco D.B. Bonifácio
Keyword(s):  
Energy Consumption ◽  
Lower Energy ◽  
Catalytic Performance ◽  
Green Technology ◽  
Waste Reduction ◽  
One Pot ◽  
Reaction Conversion

Mechanosynthesis is an emergent green technology that proceeds under solventless or vestigial solvent conditions. Major advantages relay in waste reduction and lower energy consumption, without compromising or enhancing reaction conversion....

Use of Superpave Technology for Design and Construction of Rubberized Asphalt Mixtures

1997 ◽  
Vol 1583 (1) ◽  
pp. 71-81 ◽  
Author(s):  
H. Barry Takallou ◽  
Hussain U. Bahia ◽  
Dario Perdomo ◽  
Robert Schwartz
Keyword(s):  
Fatigue Behavior ◽  
Permanent Deformation ◽  
Performance Testing ◽  
Fatigue Cracking ◽  
Asphalt Mixtures ◽  
Mix Design ◽  
Asphalt Rubber ◽  
Constant Height ◽  
Overlay Design ◽  
Gyratory Compaction

The effect of different mixing times and mixing temperatures on the performance of asphalt-rubber binder was evaluated. Four different types of asphalt-rubber binders and neat asphalt were characterized using the Strategic Highway Research Program (SHRP) binder method tests. Subsequently, mix designs were carried out using both the SHRP Levels I and II mix design procedures, as well as the traditional Marshall mix design scheme. Additionally, performance testing was carried out on the mixtures using the Superpave repetitive simple shear test at constant height (RSST-CH) to evaluate the resistance to permanent deformation (rutting) of the rubberized asphalt mixtures. Also, six rectangular beams were subjected to repeated bending in the fatigue tester at different microstrain levels to establish rubberized asphalt mixtures’ resistance to fatigue cracking under repeated loadings. The results indicate that the Superpave mix design produced asphalt-rubber contents that are significantly higher than values used successfully in the field. Marshall-used gyratory compaction could not produce the same densification trends. Superpave mixture analysis testing (Level II) was used successfully for rubberized asphalt mixtures. Results clearly indicated that the mixture selected exhibited acceptable rutting and fatigue behavior for typical new construction and for overlay design. Few problems were encountered in running the Superpave models. The results of the RSST-CH indicate that rubber-modified asphalt concrete meets the criteria for a maximum rut depth of 0.5 in.; and more consistent results were measured for fatigue performance analysis using the repeated four-point bending beam testing (Superpave optional torture testing). The cycles to failure were approximately 26,000 at 600 microstrain.

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