scholarly journals Laboratory Evaluation of Mechanical Properties of Modified Asphalt and Mixture Using Graphene Platelets (GnPs)

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5599
Author(s):  
Mohamed Samir Eisa ◽  
Ahmed Mohamady ◽  
Mohamed E. Basiouny ◽  
Ayman Abdulhamid ◽  
Jong R. Kim

Recently, nanomaterials have attracted attention in the field of pavement construction as modifiers to endure heavy loads and climate changes. In this study, conventional asphalt (bitumen) of penetration grade AC (60/70) was modified with graphene platelets (GnPs) at three different contents: 0.5%, 1.0%, and 1.5% by weight of asphalt content. Kinematic viscosity, softening point, penetration, and dynamic shear rheology tests were performed to evaluate the mechanical properties of modified binder. The results showed that adding GnPs improves the mechanical properties of asphalt binder; the kinematic viscosities, softening points, and rutting parameters increased but penetrations decreased with the contents of GnPs. Hot mix asphalt specimens with GnPs-modified asphalt were prepared and characterized with Marshall tests, thermal stress restrained specimen tests (TSRST), wheel tracking tests, and indirect tensile tests. Similar to the results of asphalt binder, the mechanical properties of asphalt mixture were improved by GnPs. Marshall stability increased by 21% and flow decreased by 24% with accepted value of 2.8 mm in penetration when the mixture was modified with 1.0 wt% of GnPs. At the same GnPs content, modified asphalt mixture led to lower failure temperature by 2 °C in comparison with unmodified asphalt mixture and the cryogenic failure stress was improved by 12%. The wheel tracking tests showed that GnPs-modified asphalt mixture has outstanding deformation resistance in comparison with unmodified asphalt mixtures: after 5000 cycles, 1.0 wt% of GnPs reduced the rut depth of asphalt mixture by 60%—the rut depth of unmodified asphalt mixture was 6.9 mm compared to 2.75 mm for modified asphalt mixture. After 10,000 cycles, the modified asphalt mixture showed rut depth of 3.24 mm in comparison with 8.12 mm in case of unmodified asphalt mixture. Addition of GnPs into asphalt mixture significantly improved the indirect tensile strength: 1.0 wt% of GnPs increased the indirect tensile strength of unmodified asphalt mixture from 0.79 to 1.1 MPa recording ~40% increment. The results of this study can confirm that graphene platelets enhance the mechanical properties of asphalt mixture and its performance.

CivilEng ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 370-384
Author(s):  
Hossein Noorvand ◽  
Kamil Kaloush ◽  
Jose Medina ◽  
Shane Underwood

Asphalt aging is one of the main factors causing asphalt pavements deterioration. Previous studies reported on some aging benefits of asphalt rubber mixtures through laboratory evaluation. A field observation of various pavement sections of crumb rubber modified asphalt friction courses (ARFC) in the Phoenix, Arizona area indicated an interesting pattern of transverse/reflective cracking. These ARFC courses were placed several years ago on existing jointed plain concrete pavements for highway noise mitigation. Over the years, the shoulders had very noticeable and extensive cracking over the joints; however, the driving lanes of the pavement showed less cracking formation in severity and extent. The issue with this phenomenon is that widely adopted theories that stem from continuum mechanics of materials and layered mechanics of pavement systems cannot directly explain this phenomenon. One hypothesis could be that traffic loads continually manipulate the pavement over time, which causes some maltenes (oils and resins) compounds absorbed in the crumb rubber particles to migrate out leading to rejuvenation of the mastic in the asphalt mixture. To investigate the validity of such a hypothesis, an experimental laboratory testing was undertaken to condition samples with and without dynamic loads at high temperatures. This was followed by creep compliance and indirect tensile strength testing. The results showed the higher creep for samples aged with dynamic loading compared to those aged without loading. Higher creep compliance was attributed to higher flexibility of samples due to the rejuvenation of the maltenes. This was also supported by the higher fracture energy results obtained for samples conditioned with dynamic loading from indirect tensile strength testing.


Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7060
Author(s):  
Mohammad Alharthai ◽  
Qing Lu ◽  
Ahmed Elnihum ◽  
Asad Elmagarhe

This study investigates the substitution of conventional aggregate with a Florida washed shell in open-graded asphalt mixtures and evaluates the optimal substitution percentage in aggregate gradations of various nominal maximum aggregate sizes (NMASs) (i.e., 4.75, 9.5, and 12.5 mm). Laboratory experiments were performed on open-graded asphalt mixture specimens with the coarse aggregate of sizes between 2.36 and 12.5 mm being replaced by the Florida washed shell at various percentages (0, 15, 30, 45, and 100%). Specimen properties relevant to the performance of open-graded asphalt mixtures in the field were tested, evaluated, and compared. Specifically, a Marshall stability test, Cantabro test, indirect tensile strength test, air void content test, and permeability test were conducted to evaluate the strength, resistance to raveling, cracking resistance, void content, and permeability of open-graded asphalt mixtures. The results show that there is no significant difference in the Marshall stability and indirect tensile strength when the coarse aggregates are replaced with Florida washed shell. This study also found that the optimum percentages of Florida washed shell in open-graded asphalt mixture were 15, 30, and 45% for 12.5, 9.5, and 4.75 mm NMAS gradations, respectively.


2012 ◽  
Vol 204-208 ◽  
pp. 3934-3937 ◽  
Author(s):  
Bao Yang Yu ◽  
Yu Wang ◽  
Min Jiang Zhang

The objectives of this paper are to characterize the mechanical properties of porous asphalt pavement mixtures containing RAP and a WMA additive using Super pave gyratory compactor and dynamic modulus testing. Four types of asphalt mixtures were evaluated in this study. This study evaluated compaction energy index, permeability, indirect tensile strength, and dynamic modulus for all types of porous asphalt mixtures. All of the asphalt mixtures meet the typical minimum coefficient of permeability in this study. In addition, only a slight decrease in was found when WMA additive was added to the porous asphalt mixture containing RAP. For indirect tensile strength testing, WMA containing RAP was found to have the highest tensile strength among all of the mixtures tested.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yongjoo Kim ◽  
Tae-Soon Park

This paper presents the reinforcing effects of the inclusion of short polypropylene fibers on recycled foamed asphalt (RFA) mixture. Short polypropylene fibers of 10 mm length with a 0.15% by weight mixing ratio of the fiber to the asphalt binder were used. The Marshall stability test, the indirect tensile strength test, the resilient modulus test, and wheel tracking test of the RFA mixtures were conducted. The test results were compared to find out the reinforcing effects of the inclusion of the fiber and the other mixtures, which included the conventional recycled foamed asphalt (RFA) mixtures; the cement reinforced recycled foamed asphalt (CRFA) mixtures; the semihot recycled foamed asphalt (SRFA) mixtures; and recycled hot-mix asphalt (RHMA) mixtures. It is found that the FRFA mixture shows higher Marshall stability than the RFA and SRFA mixtures, higher indirect tensile strength than the RFA mixture, and higher rut resistance than the RFA, SRFA, and RHMA mixtures as seen from the wheel tracking test.


Author(s):  
Shaban Ismael Albrka Ali ◽  
Riyadh Abdulwahid ◽  
Muhamed Laith Eidan ◽  
Nur Izzi Md Yusoff

Flexible pavements deteriorate and crack with time due to the frequent traffic load imposed upon it. Many studies have been done to predict the effects of frequent traffic load and environmental conditions on pavements in the effort to find the best pavement design which resist deterioration and ensure longer pavement service time. This study investigates the effect of mixing asphalt with varying percentages of nano calcium carbonate (CaCO3), namely 0, 2, 4, and 6 %. The mixtures were designed based on the Superpave mix design criteria. Investigation was done using several tests, namely resilient modulus, indirect tensile strength, moisture susceptibility, and dynamic modulus tests. Samples were subjected to aging to determine their resilient modulus. The results of the investigation show that resilient modulus and indirect tensile strength increased when higher percentages of nanoparticles were added to asphalt mixture, with improvement of 138 and 48.18% respectively. Modified binders showed up to 17% improvement in moisture susceptibility comparison to base asphalt mixture, while the result of dynamic modulus test showed that the stiffness of modified asphalt increased 76.69%. The investigation also found that adding 6% CaCO3 nanoparticles to asphalt produced modified asphalt with the best performance. In addition, the results show that the modified asphalt with CaCO3 is suitable for hot and humid regions (tropical countries) in the field of highways construction, as the modifier was able to mitigate the influences of high-temperature rutting and moisture damage.


2018 ◽  
Vol 206 ◽  
pp. 02015
Author(s):  
Martin Bitolog ◽  
Mouhamed Bayane Bouraima ◽  
Xiao-hua Zhang ◽  
Christian Magloire Ndjegwes ◽  
Yanjun Qiu

In this study, an effect of temperature on both indirect tensile strength (ITS) test and Marshall Stability Test of foam asphalt mixture using Shell #70 A asphalt is firstly investigated. A detailed investigation of the mechanical properties of foam asphalt mixture was then carried out using two different asphalt binders. The experimental work compares the mechanical properties of foam asphalt mixes including water stability test, indirect tensile strength (ITS) test, and freeze-thaw splitting test. The test results indicate that the foam asphalt mixture is temperature dependent and also temperature sensitive material. The foaming properties of asphalt have an important effect on the properties of the foam asphalt mixture for the strength and water stability of the foam asphalt mixture.


2019 ◽  
Vol 81 (6) ◽  
Author(s):  
Norfazira Mohd Azahar ◽  
Norhidayah Abdul Hassan ◽  
Ramadhansyah Putra Jaya ◽  
Hasanan Md. Nor ◽  
Mohd Khairul Idham Mohd Satar ◽  
...  

The use of cup lump rubber as an additive in asphalt binder has recently become the main interest of the paving industry. The innovation helps to increase the natural rubber consumption and stabilize the rubber price. This study evaluates the mechanical performance of cup lump rubber modified asphalt (CMA) mixture in terms of resilient modulus, dynamic creep and indirect tensile strength under aging conditions. The CMA mixture was prepared using dense-graded Marshall-designed mix and the observed behavior was compared with that of conventional mixture. From the results, both mixtures passed the volumetric properties as accordance to Malaysian Public Work Department (PWD) specification. The addition of cup lump rubber provides better resistance against permanent deformation through the enhanced properties of resilient modulus and dynamic creep. Furthermore, the resilient modulus of CMA mixture performed better under aging conditions.  


Author(s):  
Mohammadreza Kamali ◽  
Mahmoud Khalifeh ◽  
Arild Saasen ◽  
Laurent Delabroy

Abstract Integrated zonal isolation is well-known as a key parameter for safe drilling operation and well completion of oil and gas wells. An extensive research on alternative materials has been conducted in the past concerning primary cementing, overcoming annular leaks, and permanent well abandonment. The present article focuses on geopolymers, expansive cement, pozzolan based sealant and thermosetting resins. The viscous behavior and the pumpability of the different materials have been investigated and benchmarked with the properties of neat class G Portland cement. The current study includes short-term mechanical properties of the above-mentioned materials. These properties include compressive strength development, Young’s modulus, indirect tensile strength, and sonic strength. The tests are performed in accordance with API 10B-2 and ASTM D3967-16 for all the materials for 1, 3, 5, and 7-day of curing at 90°C and elevated (172 bar) and atmospheric pressures. Our results show a mixed behavior from the materials. According to uniaxial compressive test results, all the candidate barrier materials developed strength during the considered period; however, the geopolymer and pozzolanic-based mixture did not develop early strength. The expansive cement showed an acceptable early compressive strength, but strength reduction was noticed after some time. The strength reduction of expansive cement was also observed for the indirect tensile strength. All the materials become stiffer overtime as they made more strength. For the neat class G cement and expansive cement, the Young’s modulus showed a minimum after 5 days, but it was increased.


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