Permanent Deformation Characterisation of Gap-Graded and Continuous Graded Aggregate Blends for Bituminous Mixtures

Author(s):  
V. T. Thushara ◽  
J. Murali Krishnan
2020 ◽  
Vol 12 (19) ◽  
pp. 8044
Author(s):  
Raffaella Fusco ◽  
Laura Moretti ◽  
Nicola Fiore ◽  
Antonio D’Andrea

This article presents a comparative review of the most commonly used nano-additives for bituminous mixtures: nanoclays (NC), nanosilicates, carbon nanotubes (CNTs), graphene nanoplatelets (GNPs), nano-calcium oxide (CaO), and nano-titanium dioxide (TiO2). In this study, the mechanical behavior of the obtained additive mixture is evaluated. According to the revised literature, the results strongly depend on type, concentration, and dispersal of used nano-additive. In fact, it has been seen that simple shear mixing followed by sonication homogenizes the distribution of the nanoparticles within the bituminous matrix and favors the bonds’ formation. The viscosity of the mixture of bitumen with nanoparticles improves with the increase of the percentage of additive added: it indicates a potential improvement to permanent deformation and rutting. Another benefit is an increased resistance of the binder to aging. Furthermore, it has been shown that the nanoparticles are able to prolong the service life of a bituminous mixture by means of various interdependent chemical–physical mechanisms that can influence the resistance to fatigue failure or the ability to self-heal. However, the effectiveness of these improvements depends on the particle type, added quantity and mixing technique, and the tests carried out.


Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1241
Author(s):  
Giuseppe Piccone ◽  
Giuseppe Loprencipe ◽  
Arminda Almeida ◽  
Nicola Fiore

In the last decades, all technology production sectors reached a high level of development, without neglecting the attention to environmental aspects and safeguarding energy resources. Moreover, in the sector of pavement industry, some alternatives of bituminous mixtures were proposed to reduce the greenhouse gas emissions. One of these is the warm mix asphalt (WMA), a mixture produced and compacted at lower temperatures compared to traditional hot mix asphalt (HMA) (about 40 °C less), to allow a reduction of emissions into the atmosphere and the costs. Other operative benefits concern the health of workers during the whole road construction process, the reduction of distances to which the mixture can be transported, and therefore also the positioning of the plants. However, it is not all benefits, since reduced production temperatures can bring short- and long-term water sensitivity issues, which could threaten the pavement performance. This paper evaluated the performance (water sensitivity, stiffness, fatigue, and permanent deformation) of a WMA produced using a warm mix fabrication bitumen and compared it with an HMA tested in parallel. In general, except for the resistance to permanent deformation, the WMA presented performances comparable to HMA. Regarding the fatigue behavior of asphalt mixtures, the WMA was less affected by ageing conditions, despite it showing lower performance than HMA.


2001 ◽  
Vol 2 (1) ◽  
pp. 7-28 ◽  
Author(s):  
Andrew C Collop ◽  
Shahab Khanzada

2001 ◽  
Vol 2 (1) ◽  
pp. 7-28
Author(s):  
Andrew C. Collop ◽  
Shahab Khanzada

2016 ◽  
Vol 43 (5) ◽  
pp. 402-410 ◽  
Author(s):  
Baha Vural Kök ◽  
Mehmet Yilmaz ◽  
Mustafa Akpolat

Recently, crumb rubber (CR) obtained from waste tires and Fischer–Tropsch paraffin are mostly used in bitumen modification to improve the performance of bituminous mixtures. Each of these additives affects the different properties of mixtures. There are limited studies in the literature about the combined usage of additive in the same mixture to utilize the different characteristics. In this study, the stability, stiffness, fatigue resistance, permanent deformation resistance, and moisture susceptibility characteristics of the stone mastic asphalt prepared with the bitumen modified with CR and paraffin were examined and compared with the control mixture. It was determined that CR-modified mixtures showed significantly more elastic characteristics. The mixture in which the 10% CR and 3% paraffin were used together gave better results in terms of moisture susceptibility and fatigue resistance when compared with the control mixture. It was determined that the use of paraffin together with CR contributed to the improved performance, and was in accordance with the CR in terms of mechanical characteristics of stone mastic asphalt.


2008 ◽  
Vol 9 (3) ◽  
pp. 537-547 ◽  
Author(s):  
Dinis Gardete ◽  
Luís Picado Santos ◽  
Jorge Pais

2021 ◽  
Vol 1203 (3) ◽  
pp. 032093
Author(s):  
Stanisław Majer ◽  
Bartosz Budziński

Abstract The use of additives in bituminous mixtures such as fibers has been the subject of various studies. Different fibres including cellulose fibres, steel fibres, basalt fibres, glass fibres and aramid fibres can be used to improve the properties of bituminous mixtures. Depending on the type of fibres used, different characteristics can be changed. The paper contains results of comparative tests of bituminous mixtures with aramid-polyolefin fibres. Asphalt concrete used for wearing course with maximum aggregate size of 11 mm was evaluated in the study. Reference mix with an average penetration grade of 50/70 was chosen as a base for modifications. Due to difficulty in preparing mixtures with fibers in a laboratory mixer, test specimens were obtained from a stationary plant. The fibers and aggregate mix was prepared before adding the asphalt. The fibers were added at a rate of 0.5 kg per 1000 kg of finished bituminous mixture. This allowed to obtain an even distribution of fibers in the mixture resulting in a homogeneity necessary for planned tests. This allowed to omit the scale effect, that could occur due to differences between laboratory and stationary mixing. Stiffness modulus tests were performed using the IT-CY (Indirect Tension to Cylindrical Specimens) method for a wide temperature range of 0-30°C. The specimen resistance to permanent deformation was evaluated. Obtained results has shown a clear increase in the resistance to permanent deformation of mixtures with aramid- polyolefin fibers, which is especially important for mixtures used for wearing course. The results has also shown a significant increase in the stiffness modulus regardless of temperature range. Results of conducted experiments has shown that it is possible to reduce the thickness of bituminous overlay in case of reinforcement of the existing pavement structure. The analysis of results has shown that the application of aramid-polyolefin fibres in bituminous mixtures can improve the functional features of the pavement and be beneficial to the investors.


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