Performance Evaluation of Plant Produced Warm Mix Asphalt

2018 ◽  
Vol 24 (5) ◽  
pp. 145 ◽  
Author(s):  
Amjad H. Albayati

Warm mix asphalt (WMA) is relatively a new technology which enables the production and compaction of asphalt concrete mixtures at temperatures 15-40 °C lower than that of traditional hot mix asphalt HMA. In the present work, six asphalt concrete mixtures were produced in the mix plant (1 ton each) in six different batches. Half of these mixes were WMA and the other half were HMA.  Three types of fillers (limestone dust, Portland cement and hydrated lime) were used for each type of mix. Samples were then taken from these patches and transferred to lab for performance testing which includes: Marshall characteristics, moisture susceptibility (indirect tension test), resilient modulus, permanent deformation (axial repeated load test) and fatigue characteristics (third point flexural beam test). The obtained results indicated that the performance of WMA is enhanced when using the hydrated lime as filler in comparison with the limestone dust and Portland cement fillers. Better fatigue life was obtained for WMA using hydrated lime filler in comparison with HMA. Regardless the filler type, the Marshall properties of WMA satisfy the requirement of local specification, other properties of WMA were relatively lower than the HMA.  

2015 ◽  
Vol 4 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Ahmed F. Al-Tameemi ◽  
Yu Wang ◽  
Amjad Albayati

Abstract Flexible or asphalt concrete pavement is the paving system most widely adopted all over the world. It has been recognized that there are many different types of the factors affecting the performance and durability of asphalt concrete pavement, including the service conditions, such as: the variation of temperature from mild to extremes and the repeated excessive axle loading as well as the inadequate quality of the raw materials. All of these when combined together are going to accelerate the occurrence of distresses in flexible pavement such as permanent deformation and fatigue cracking. As the result, there has an urgent need to enhance the ability of asphalt concrete mixture to resist distresses happened in pavement. Use of additives is one of the techniques adopted to improve pavement properties. It has been found that hydrated lime might be one of the effective additives because it is widely available and relatively cheap compared to other modifiers like polymers. This paper presents an experimental study of the hydrated-lime modified asphalt concrete mixtures. Five different percentages of the hydrated lime additive were investigated, namely (1, 1.5, 2, 2.5 and 3 percent). The hydrated lime additive was used as partial replacement of limestone filler by total weight of the aggregate. The designed Hot Mix Asphalt (HMA) concretes are for the application of three pavement courses, i.e. Surface, Leveling and Base. These mixtures are designed and tested following Marshall procedure and uniaxial repeated loading to evaluate permanent deformation at different temperatures of 20°C, 40°C and 60°C. The experimental results show that the addition of hydrated lime as a partial replacement of ordinary limestone mineral filler results a significant improvement on mechanical properties and the resistant to permanent deformation of the designed asphalt concrete mixtures.


Author(s):  
Ahmed M. Mohammed ◽  
Aqeel T. Fadhil

Mineral filler is the finest fraction of aggregate (smaller than 75 gm) used in the production of asphalt paving mixed. It is essential for producing a mixture that is dense, cohesive, durable, and resistant to water penetration. In spite of the fact that filler is very small proportion of the total aggregates in the mix, due to its rather high affinity for asphalt, the changes in the type of the filler can cause the paving mixture to perform satisfactorily during the design life or deteriorate rapidly under the effect of traffic and environmental impact. The objective of this study is to investigate the effect of mineral filler types (three types, limestone dust, Portland cement and hydrated lime) in the durability of asphalt concrete mixture. To achieve the objective of this study, Marshall mix design method was utilized to produce asphalt concrete mixes at their optimum asphalt content. The mixes were, then, tested to investigate their durability properties including moisture damage and fatigue characteristics. The results indicated that the mixes prepared with hydrated lime have superior resistance to moisture damage in comparison with Portland cement and lime stone dust. On the other hand, the mixes prepared with Portland cement type of filler showed better resistance to the fatigue failure of asphalt concrete pavement.


2021 ◽  
Vol 27 (2) ◽  
pp. 59-72
Author(s):  
Zahraa Ahmed Samor ◽  
Saad Issa Sarsam

Laboratory experience in Iraq with cold asphalt concrete mixtures is very limited. The design and use of cold mixed asphalt concrete had no technical requirements. In this study, two asphalt concrete mixtures used for the base course were prepared in the laboratory using conventional cold-mixing techniques to test cold asphalt mixture (CAM) against aging and moisture susceptibility. Cold asphalt mixtures specimens have been prepared in the lab with cutback and emulsion binders, different fillers, and curing times. Based on the Marshal test result, the cutback proportion was selected with the filler, also based on the Marshal test emulsion. The first mixture was medium setting cationic emulsion (MSCE) as a binder, hydrated lime, and ordinary portland cement as a filler (7.95% MSCE + 2%HL + 3% OPC). The second mixture used was medium curing cutback (MC-250) as a binder and ordinary portland cement as a filler (5.18% MC 250 + 5% OPC). The indirect tensile strength (ITS) of the samples was measured at 25 ° C. It was found that the cold mix with the MSCE binder had a high ITS value relative to the cold mix with the cutback asphalt binder (MC-250). The dry mixture of MSCE  ITS was approximately 3.77 times the dry mixture of MC-250. The MSCE wet mix was about 4.2 times the wet MC-250 mix. Tensile strength ratio result (TSR %) for the MSCE binder mix and the cutback MC-250 binder mix showed that the MSCE mix has a reasonable moisture resistance (77% ) compared to the MC-250 mix (69.2 %). The aging test and aging ratio result showed that asphalt binder oxidation has a significant effect on age-related pavement degradation as it changes the time-temperature relationship depending on the viscoelastic properties of the asphalt binder. The result clearly showed that the MSCE binder mix had a high resistance to aging (440 Kpa) compared to the cutback (MC-250) binder mix (110 Kpa). In contrast, the MSCE aging ratio (90 %) was higher than the MC-250 ratio (85 %).


2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Saad Issa Sarsam ◽  
Zahraa Ahmed Samor

Cold mix asphalt concrete is considered as a sustainable and green pavement, the aggregates and the binder can be mixed, laid, and compacted without consumption of energy. In this investigation, an attempt has been made to prepare cold mix asphalt concrete for base course construction. Two types of liquid binder, named Cationic emulsion Medium Setting CMS and Medium Curing cutback MC-250 have been implemented in preparation of Marshall specimens. Four types of additives, named Portland cement, coal fly ash, limestone dust and hydrated lime have been tried. Mixtures were subjected to aeration, then compacted. However, Specimens were subjected to curing before testing. It was concluded that mixtures with (optimum cutback content + 5% cement and 4 hours aeration and 24 hours curing at 60°C) and (optimum emulsion content +2% hydrated lime +3% cement or fly ash and 4 hours aeration at 25°C and 24 hours curing at 60°C) satisfies the volumetric and Marshall properties requirements for base course. It was recommended that increasing the aeration and curing periods is beneficial for the cold mix asphalt concrete in satisfying the specification requirements for base course. Keywords:Cold Mix; Asphalt Concrete; Cement; Lime; Fly ash; Marshall; Aeration; Curing;


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4731
Author(s):  
Mateusz M. Iwański

Half-warm mix asphalt (HWMA) mixtures can be produced at temperatures ranging from 100 °C to 130 °C, depending on the production methods used. The lowest mixing temperature can be achieved by using water-foamed bitumen. The mixture should be characterized by a long service life, defined by the resistance to permanent deformation and high stiffness modulus at temperatures above zero. It is therefore important to ensure the adequately high quality of the bitumen binder. Bitumen 50/70 was provided with appropriate quality foaming characteristics (expansion ratio, ER, half-life, t1/2) by adding a surface-active agent (SAA) at 0.6 wt % before foaming. Then asphalt concrete (AC) 8 S was designed and produced with the recommended water-foamed binder. Hydrated lime, an additive substantially affecting asphalt concrete mechanical parameters, was used at 0, 15, 30, and 45 wt % as a partial replacement for the limestone filler. The influence of the amount of hydrated lime on the content of voids, indirect tensile stiffness modulus at −10 °C, 0 °C, +10 °C, +20 °C, and +30 °C, and the resistance to permanent deformation was investigated. Statistical analysis of the test results showed the quantity of 30% to be the optimum hydrated lime content. The AC 8 S resistance to permanent deformation was determined at the optimum hydrated lime content. The comprehensive evaluation revealed a synergistic effect between bitumen 50/70, modified before foaming with 0.6 wt % SAA and 30 wt % hydrated lime as the limestone filler replacement, and the half warm mixture AC 8 S, in terms of the standard requirements and durability of the HWMA concrete in pavement applications.


2016 ◽  
Vol 28 (5) ◽  
pp. 04015205 ◽  
Author(s):  
Akshay Gundla ◽  
Jose Medina ◽  
Padmini Gudipudi ◽  
Ryan Stevens ◽  
Ramadan Salim ◽  
...  

2013 ◽  
Vol 646 ◽  
pp. 90-96 ◽  
Author(s):  
Aboelkasim Diab ◽  
Zhan Ping You ◽  
Hai Nian Wang

Two Nano Hydrated Lime (NHL) materials with particle sizes of 50 nm and 100 nm were used in this study to investigate to the effect of NHL modification on the creep and recovery of Warm Mix Asphalt (WMA) binders foamed using Advera® with respective to rutting. The NHL was added to the asphalt binder at ratios of 20%, 10%, and 5% by weight of the asphalt binder. The creep and recovery tests were performed at three different stress levels, 3Pa (creep for 100 sec. and 600 sec. recovery), 10Pa (creep for 20 sec. and 600 sec. recovery), and 50Pa (creep for 1 sec and 300 sec. recovery). The tests were performed at a temperature of 58oC. The results were also compared with the Regular Hydrated Lime (RHL) results. The overall results reveal that the neat asphalt binders foamed using advera® showed larger permanent deformation (rutting) potential compared to the binder modified with RHL and NHL foamed using Advera®. As the NHL dose increases, the non-recoverable compliance decreases (rutting decreases). It was also concluded that the application of the RHL with the normal dose (20% by weight of binder) can be replaced by adding 5% (by weight of binder) of 50 nm NHL with respective to rutting.


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