scholarly journals Structural sensitivity of an asphalt pavement to asphalt binder content and mix design method

TRANSPORTES ◽  
2021 ◽  
Vol 29 (4) ◽  
pp. 2456
Author(s):  
Cássio Alberto Teoro Do Carmo ◽  
Géssica Soares Pereira ◽  
Geraldo Luciano de Oliveira Marques ◽  
Paulo Roberto Borges

The goal of this study was to analyze the structural sensitivity of a flexible pavement, whose asphalt layers underwent variations in its mechanical properties due to the asphalt binder content and the mix design method Marshall and Superpave. A variation of ±0.5% within the optimum asphalt binder contents was used (service tolerance) considering possible permissible variations in the asphalt binder content during the asphalt mixture manufacturing process. The values of resilient modulus and indirect tensile strength (Brazilian test) of the resulting asphalt mixtures were applied to the reference pavement structure analyzed by the me-PADS software. The results show that the variations in the asphalt binder content and the asphalt mixtures design method influence the mechanical properties and corresponding structural responses of the pavement investigated: the asphalt layers designed by the Marshall method presented greater sensitivity to the variation in asphalt binder content, which may constitute a technical differential of asphalt mixtures designed by the Superpave method.

DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 184-191
Author(s):  
Heraldo Nunes Pitanga HERALDO PITANGA ◽  
Tamyres Karla da Silva ◽  
T.O Silva ◽  
Geraldo Luciano De Oliveira Marques

This study aimed to analyze the influence of different methodologies to determine the maximum specific gravity on the Superpave mix design method. The comparative analysis focused on the volumetric parameters, on the choice of the design particle size and, consequently, on the respective design asphalt binder contents of the studied asphalt mixtures. Regarding the particularities of the research, there were no significant differences in the design binder contents obtained using the two adopted methodologies for determining the maximum specific gravity. From a practical point of view, the adoption of any of the methods interfered little with the results of the application of the Superpave mix design method. This fact demonstrates a quality of this method since similar researches based on the Marshall design method evidences the sensitivity of the protocol for determining the asphalt binder content in relation to the used type of maximum specific gravity.


Author(s):  
Shashwath Sreedhar ◽  
Erdem Coleri ◽  
Ihsan Ali Obaid ◽  
Vikas Kumar

Most state Departments of Transportation (DOTs) and asphalt contractors do not think that commonly used asphalt mixture properties, such as voids in mineral aggregate (VMA), voids filled with asphalt (VFA), and dust-to-binder ratio, reflect the long-term performance of asphalt mixtures. In addition, there are several new additives, polymers, rubbers, and high-quality binder types incorporated into asphalt mixtures today. Volumetric mixture design methods are not capable of capturing the benefits of using all these new technologies on asphalt mixture performance. Furthermore, the interaction of virgin binders with reclaimed asphalt pavement (RAP) mixtures with high binder replacement contents and the level of RAP binder blending into the asphalt mixture are still not well understood. Because of all these complications related to the more complex structure of asphalt mixtures, simple volumetric evaluations to determine the optimum binder content may not result in reliable asphalt mixture designs. Two volumetrically identical mixtures may provide completely different rutting and cracking performance according to laboratory tests. For all these reasons, in this study performance tests for rutting and cracking are incorporated into current asphalt mixture design methods to make it possible to validate or revise the optimum binder content determined by the volumetric mix design method (the only method currently used for asphalt mix design).


Author(s):  
Jamilla Emi Sudo Lutif Teixeira ◽  
Aecio Guilherme Schumacher ◽  
Patrício Moreira Pires ◽  
Verônica Teixeira Franco Castelo Branco ◽  
Henrique Barbosa Martins

The influence of steel slag expansion level on the early stage performance of hot mix asphalt (HMA) is evaluated. Initially, samples of Linz-Donawitz type steel slag with different levels of expansion (6.71%, 3.16%, 1.33%) were submitted to physical, mechanical, and morphological characterization to assess the effects of expansion on individual material properties. Steel slag was then used as aggregate in HMA to verify the effects of its expansion characteristics on the volumetric and mechanical performance of the asphalt mixture. Four different asphalt mixtures were designed based on Marshall mix design, using asphalt cement (pen. grade 50/70), natural aggregate (granite), and steel slag (in three different levels of expansion). The mechanical characteristics of the asphalt mixture were evaluated based on results from Marshall stability, indirect tensile strength, and resilient modulus testing. A modified Pennsylvania testing method (PTM) was also performed on the studied asphalt mixtures to verify the potential of asphalt binder film to minimize the expansive reactions of steel slag. It was observed that the level of steel slag expansion changes some of the material’s individual properties, which can affect the volumetric parameters of the mix design. The use of steel slag as aggregate in HMA also improves the mechanical properties of non-aged asphalt mixtures. Moreover, the expansive characteristics of this material could be minimized when combined with other asphalt mixture components.


2020 ◽  
Vol 41 (2) ◽  
pp. 157
Author(s):  
Fernanda Gadler ◽  
Leonardo Fagundes Rosemback Miranda ◽  
Joe Villena

The main purpose is to evaluate the performance of asphalt regarding resilient modulus and fatigue curve.The asphalt was produced with two wastes, reclaimed asphalt pavement (RAP) and recycled concrete aggregate (RCA), using the technique of warm mixtures. The evaluation includes, based on these parameters, the thickness differences in the design of asphalt layer for each mixture. Five asphalt mixtures were produced with incorporation of RAP and RCA, in different gradation fractions (fine and/or course), without adding any natural aggregate. In view of the aim of the article, the mixtures were evaluated through tests of resilient modulus and fatigue life, in order to support the design, establishing the necessary thickness to meet traffic demands of each mixture. The design was performed using MeDiNa software. Among all results, it is highlighted that asphalt binder content is the component that exerts the greatest influence on the resilient modulus of the mixtures. As for fatigue, in addition to the binder content, the possible anchoring of the asphalt binder in the pores of the RCA may have favored the performance of the GARC_MRAP mixture. Still, all mixtures with RAP, both in fine or course fraction, resulted in lower coating thicknesses compared to the REF, for the same load request, with better performance of the GARC_MRAP mixture produced with 100 % waste material and incorporation of only 3.1 % neat binder.


Author(s):  
Ahmed Saidi ◽  
Ayman Ali ◽  
Wade Lein ◽  
Yusuf Mehta

The objective of this paper is to present a procedure for designing cold in-place recycling (CIR) mixtures through balancing rutting and cracking for these mixtures. Four CIR mixtures were prepared using two recycling agents (foamed and emulsified asphalts), and compacted at two gyration levels (30 and 70 gyrations). The CIR mixtures were prepared at a constant water content of 3% and a constant cement content of 1% while curing of the compacted samples was conducted by placing them in an oven for three days at 140°F (dry curing). The CoreLok device was used for measuring air voids in compacted samples. The rutting susceptibility of these mixtures was then evaluated using the asphalt pavement analyzer (APA) and dynamic complex modulus (|E*|) while resistance to cracking was assessed using the indirect tensile strength (ITS) test and fracture energy as determined using the semi-circular bend (SCB-FE) test. A demonstration of how these tests were utilized to select a performance balanced optimum binder content for each of the four CIR mixes was also presented. The developed balanced mix design approach was used successfully for designing four CIR mixtures and selecting the optimum binder content for each mix. The results also showed that using a higher compaction level leads to increasing both foamed and emulsified asphalt CIR mixtures’ ability to resist rutting. In terms of cracking, SCB-FE results showed that foamed asphalt mixtures were better at resisting cracking than emulsified asphalt CIR mixtures.


2016 ◽  
Vol 78 (7-2) ◽  
Author(s):  
Khairil Azman Masri ◽  
Ahmad Kamil Arshad ◽  
Mohamad Saifullah Samsudin

This paper evaluates the mechanical properties of porous asphalt (PA) with nanosilica (NS) modified binder in terms of its Abrasion Loss, Binder Draindown, Resilient Modulus and Moisture Susceptibility. These tests are essential to evaluate the performance of NS-PA towards the resistance of moisture induced damage, external loads, abrasion and interlocking structure of PA. Due to porous nature of PA, it is expose to moisture damage and binder draindown. Besides that, raveling is another major problem that closely related to PA. Thus, nanotechnology was promoted in this study in order to enhance the performance of PA. Six different percentages of nanosilica were mixed with PEN 60-70 type of binder in this study. Then, all these blended modified binder were used to prepare PA samples using Marshall Mix Design Method. Nanoparticle used in this study was Nanosilica with the average size of 10 to 15 nanometer. Binder Draindown Test was done using a metal basket with 3mm perforation. Then, abrasion loss value was evaluated using Los Angeles Abrasion Machine without steel ball. In accordance to Public Work Department of Malaysia Specification (JKR/SPJ/2008), it is stated that binder draindown for PA should not be more than 0.3% of total weight of sample, while abrasion loss should not be more than 15% also by weight of total sample. The results for Cantabro Loss Test and Binder Draindown Test indicated that 4% NS was the effective amount of NS to reduce the abrasion loss and binder drained of NS-PA. The maximum resilient modulus value for NS-PA was 4362 MPa while TSR value 91% (2% NS). Meanwhile, for conventional PA (0% NS), resilient modulus value was only 3036 MPa and TSR value 74%. From both tests were also concluded that the optimum amount of NS required for PA to archieved both value was 2%. It can be concluded that with proper concentration, the existence of NS is capable to enhance the physical and rheological properties of asphalt binder and at the same time it dispersed well in asphalt binder. Thus, the performance of PA with NS modified binder is also enhanced.


2020 ◽  
Vol 12 (7) ◽  
pp. 2716
Author(s):  
Ali Babalghaith ◽  
Suhana Koting ◽  
Nor Sulong ◽  
Mohamed Karim ◽  
Syakirah Mohammed ◽  
...  

Aggregate composition has a pivotal role in ensuring the quality of pavement materials. The use of waste materials to replace the aggregate composition of asphalt pavement leads to green, sustainable, and environmentally friendly construction, which ultimately preserves nature by reducing the need to harvest materials from natural sources. Using the Marshall mix design, the main objective of this paper is to investigate the effects of waste palm oil clinker (POC) as fine aggregates replacement on the properties of stone mastic asphalt (SMA) mixture. Six groups of asphalt mixtures were prepared using different percentages of palm oil clinker content (0%, 20%, 40%, 60%, 80%, and 100%). To determine the Marshall properties and select the optimum binder content, asphalt mixture samples with different percentages of asphalt binder content (5.0%, 5.5%, 6.0%, 6.5%, and 7.0%) were prepared for each group. The results showed that the palm oil clinker was appropriate for use as a fine aggregate replacement up to 100% in SMA mixture and could satisfy the mix design requirements in terms of Marshall stability, flow, quotient, and volumetric properties. However, the percentage of palm oil clinker replacement as fine aggregate has merely influenced the optimum binder content. Furthermore, there were improvements in the drain down, resilient modulus and indirect tensile fatigue performances of the SMA mixture. In conclusion, the use of POC as fine aggregates replacement in SMA mixture indicates a good potential to be commercialized in flexible pavement construction.


CivilEng ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 396-405
Author(s):  
Kazem Jadidi ◽  
Mehdi Khalili ◽  
Moses Karakouzian

The non-destructive ultrasound technique is an easy and inexpensive technique widely used in industry to evaluate the properties of engineering materials. Despite its popularity in industrial applications, such as evaluating steel materials, the ultrasound technique has not been thoroughly investigated for the purpose of characterizing asphalt materials in general, nor specifically determining the asphalt binder content of asphalt mixtures. The purpose of this study was to explore the feasibility of utilizing measurements based on the non-destructive ultrasound technique to detect changes in the asphalt binder content in asphaltic mixture specimens. Two performance-grade binders, PG64-28 and PG76-22, and two rubber-modified binders were selected. The rubber-modified binders were produced by adding crumb rubber to the two performance-grade binders, PG64-28 and PG76-22, and were designated as PG64-28R and PG76-22R. The amount of crumb rubber added to these rubber-modified binders was 15% by weight of the PG64-28 and PG76-22 binders. The aggregate gradations for all of the asphalt mixtures were the same. The asphalt mixture specimens were used to obtain measurements for: (1) the ultrasound wave speed through the specimens; and (2) and the integrated response (IR) of the specimens. The results indicated that, generally, the ultrasound wave speed decreases with an increase in binder content. This is expected due to the binder’s attenuation and slowing effect on the wave speed. The results also indicated that, generally, the integrated response (IR) decreases with an increase in binder content. This can be explained by the fact that the increased binder content in asphalt mixture specimens increases their tendency to absorb more energy.


2012 ◽  
Vol 490-495 ◽  
pp. 2540-2545
Author(s):  
Wen Yuan Xu ◽  
Chun Yao Deng ◽  
Hong Yu Yang

The stress-absorbing interlayer of modified asphalt mixture studied in this report is a special asphalt pavement mixture. Capable of delaying the occurrence of reflection cracks, the asphalt mixture is mainly composed of aggregate passing through a 9.5 mm sieve, machine-made or natural sand, and modified asphalt binder.


2021 ◽  
Vol 8 ◽  
Author(s):  
Hasanain Radhi Radeef ◽  
Norhidayah Abdul Hassan ◽  
Ahmad Razin Zainal Abidin ◽  
Mohd Zul Hanif Mahmud ◽  
Nur Izzi Md. Yusoffa ◽  
...  

In recent years, the proliferation of plastic waste has become a global problem. A potential solution to this problem is the dry process, which incorporates plastic waste into asphalt mixtures. However, the dry process often has inconsistent performance due to poor interaction with binder and improper distribution of plastic waste particles in the mixture skeleton. This inconsistency may be caused by inaccurate mixing method, shredding size, mixing temperature and ingredient priorities. Thus, this study aims to improve the consistency of the dry process by comparing the control asphalt mixture and two plastic waste-modified asphalt mixtures prepared using the dry process. This study used crushed granite aggregate with the nominal maximum aggregate size of 14 mm whereas the shredded plastic bag is in the range of 5–10 mm. Quantitative sieving analysis and performance tests were carried out to examine the effects of plastic waste added into the asphalt mixture. The volumetric and performance properties combined with image analysis of the modified mixtures were obtained and compared with the control mixture. In addition, the moisture damage, resilient modulus, creep deformation and rutting were evaluated. This study also highlighted in detail the distribution of plastic particles in the final skeleton of the asphalt mixture. Based on the analysis, an enhanced dry process of mixing procedure was proposed and evaluated. Results showed that the addition of plastic particles using the conventional dry process leads to the deviation in the aggregate structure as high plastic content is added. Furthermore, the enhanced dry process developed in this study presents substantial enhancement in the asphalt performance, particularly with plastic waste that accounts for 20% of the weight of the asphalt binder.


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