scholarly journals Laboratory Evaluation of the Use of Florida Washed Shell in Open-Graded Asphalt Mixtures

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.

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 575
Author(s):  
Sanja Dimter ◽  
Miroslav Šimun ◽  
Martina Zagvozda ◽  
Tatjana Rukavina

Today, the road construction profession is more than ever facing limited and increasingly expensive resources for component materials of asphalt mixtures, which has also led to the need for continuous research on the use of waste materials. One such potentially usable waste material is ash obtained by the combustion of wood biomass that is used to produce heat and electricity. The goal of this paper is to ascertain the possibility of using wood ash (WA) as the filler in asphalt concrete mixtures for the base-wearing layers of a pavement. The properties of Marshall stability (MS), quotient (MQ) and deformations, and the indirect tensile strength of water-conditioned samples and dry samples were tested on asphalt samples of an AC16 surf mixture with different contents of wood ash as the filler. The obtained values of MS and MQ indicate that a 50% content of bio ash in the filler results in an increase in asphalt’s resistance to the appearance of plastic deformations and greater tensile strength and in good asphalt resistance to the action of water.


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.


2011 ◽  
Vol 255-260 ◽  
pp. 3432-3436
Author(s):  
Xian Yuan Tang ◽  
Jie Xiao

This paper systematically elaborates the impact upon performance of emulsion asphalt cold reclaimed asphalt mixture by different RAP contents, through a series of testing on six cold reclaimed asphalt mixtures with various RAP contents, such as single axle compression test, 15°C indirect tensile strength (ITS) test, 40°C rutting test and -10°C low-temperature bending beam test. Testing results indicate that 15°C ITS decreases from around 0.75 MPa to 0.58 MPa with the RAP content of mixture increasing from 0% to 100%. 40°C dynamic stabilities reduce considerably from around 19,000 time/mm of 0% RAP mixture to 3,600 time/mm of 100% RAP mixture. -10°C failure strains only change from 1500με to 2000με.


2016 ◽  
Vol 700 ◽  
pp. 227-237 ◽  
Author(s):  
Siti Nur Amiera Jeffry ◽  
Ramadhansyah Putra Jaya ◽  
Norhafizah Manap ◽  
Nurfatin Aqeela Miron ◽  
Norhidayah Abdul Hassan

Significant quantities of coconut shell (CS), a by-product of agriculture, can be used as an artificial source of coarse aggregates. In this study, four CSs were used as coarse aggregates replacement in asphalt concrete with 0%, 10%, 20%, 30%, and 40% weight volumes. The particle sizes of the CSs used as main coarse aggregates range from 5 mm to 20 mm. The Marshall Stability test shows that the optimum bitumen content for asphalt mixtures is 5.1%. The engineering properties investigated include the volumetric, dynamic creep, indirect tensile strength, and resilient modulus. Test results show that stability decreases with increasing CS content because of high water absorption. Considering that CSs absorb bitumen, a further detailed investigation is needed to assess the performance of modified bitumen on mixture. Furthermore, the use of CSs as coarse aggregates in asphalt concrete help increase the resilient modulus, stiffness, and indirect tensile strength up to 30%. Generally, a 10% replacement of coarse aggregates with CSs is the optimal limit.


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.


2020 ◽  
Vol 38 (5A) ◽  
pp. 789-800
Author(s):  
Duaa A. Khalaf ◽  
Zaynab I. Qasim ◽  
Karim H. Al Helo

This research investigates the behavior of Stone Matrix Asphalt mixtures (SMA) modified with styrene-butadiene-styrene (SBS) polymer at four percentages (1, 2, 3 and 4%) by weight of asphalt cement. The moisture susceptibility and rutting were taken into consideration in this study. To achieve the objective of this research the superpave system is conducted to design the asphalt mixtures. The physical properties of aggregate, bitumen and other mix materials were assessed and evaluated with the laboratory tests. The mixtures were prepared using penetration Graded (40-50) bitumen and a chemical named Polypropylene Fibers was used as a stabilizing additive. Fibers have been used in SMA mixtures for two main reasons: To increase the toughness and fracture resistance of hot mix asphalt (HMA) and to act as a stabilizer to prevent drain down of the asphalt binder. The laboratory tests include indirect tensile strength test, Marshall stability and retained Marshall Stability test (RMS). For rutting test the Roller wheel compactor is used for preparing the asphaltic samples and Wheel tracking device is used to evaluate the rutting of asphaltic slabs. The results showed that the SBS polymer asphalt mixture gave better moisture sensitivity and better fracture resistance according to the study.It is noted that indirect tensile strength ratio (TSR) increases by 93.1 % and the rut depth decreases by 32.5 % when adding 3% SBS polymer to SMA.


2019 ◽  
Vol 5 (2) ◽  
pp. 320
Author(s):  
Gholam Hossein Hamedi

Several parameters affect asphalt mix performance against loading and environmental conditions. Minor changes in the filler amount or type can cause obvious changes in the asphalt mixture properties. Accordingly, in this research attempts have been made to optimally make asphalt mixture strong against loading and environmental conditions by changing the type, size and percentage of filler used in asphalt mixture. In this line, the effect of two types of cement and nano-silica fillers in two different percentages was investigated and compared as an alternative for part of the main filler in asphalt mixture samples made by two types of limestone and granite aggregate. Cement filler by 2% and 4% of the aggregate mass as the alternative for part of the main filler is added to stone materials before mixing with binder, but nano-silica filler by 2% and4 % of weight of the binder as the alternative for part of the main filler is added to binder and a modified and homogeneous binder is produced using a high speed mixer. In the following, considering the optimum binder content for each mixture, resilient modulus tests were conducted to determine the strength performance against loading and indirect tensile strength ratio was used to determine moisture sensitivity of asphalt mixtures. Results obtained from resilient modulus tests show that the use of nano-silica and cement has been capable of favorably improving the resilient modulus of samples containing these two types of fillers. The improvement of the resilient modulus of samples containing nano-silica is very significant. Additionally, the studies conducted based on the indirect tensile strength ratio show that both types of alternative fillers, especially cement has been capable of desirably improve the strength of asphalt mixtures against moisture damage.


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.


2021 ◽  
Vol 28 (3) ◽  
pp. 129-145
Author(s):  
Ahmed Almuhmdi ◽  
 Abdulbasit Muhmood ◽  
Abdulhakim Salih

The recycling of waste requires large areas; besides recycling wastes to their origin is often economically and environmentally costly. Glass is considered as a solid waste that is difficult to dispose of; it doesn't degrade nor burn. Since glass is a silicic substance with similar properties to aggregates, it can be recycled in asphalt mixtures. This research aims to determine optimum binder content (OBC) of conventional hot asphalt mixture (HMA), (control mixture), and investigate the effect of crushed glass waste (CGW), on its properties. In this work, several percentages of CGW (10%, 15%, 20%, and 25%) have been used as a partial substitution for the weight of fraction size 2.36-0.075mm of natural aggregate to prepare glass-contained asphalt mixtures and compare their properties with the control mixture. Mix design by Marshall method was used, and the properties according to Iraqi standards (SORB/R9,2003), for binder layer, were found, as well as conducting of Retained Marshall stability (RMS), indirect tensile strength (IDT), and tensile strength ratio (TSR), tests on mixtures, as performance tests. The results showed that the OBC of the control mixture was 5% wt., and the Marshall stability and flow values of glass-contained asphalt mixtures were oscillating around the values of the control mixture. The air voids, voids in mineral aggregate, and bulk density were reduced regularly as CGW increased. Also, it was observed from the results that the glass-contained mixtures have good performance properties. However, all results conformed to the standards (SORB/R9, 2003). So, the incorporation of CGW in HMA for the binder layer is feasible.


2018 ◽  
Vol 773 ◽  
pp. 271-277
Author(s):  
Kang Hun Lee ◽  
Man Ho Kook ◽  
Dong Ho Ha ◽  
Soo Ahn Kwon ◽  
Moon Sup Lee

Recently, potholes have drawn attention as a major pavement distress. In Korea and other countries, slaked lime is used to improve the moisture resistance of asphalt mixtures in order to prevent road damages by moisture. The present study was conducted to evaluate the moisture resistance of asphalt mixtures containing air-cooled slag having a chemical composition similar to that of slaked lime. To evaluate the moisture resistance of asphalt mixtures containing air-cooled slag, a moisture resistance test that is applied in Korea and other countries was performed. The evaluation of the moisture resistance of asphalt mixtures containing air-cooled slag showed that the coverage ratio measured by the dynamic immersion test was about 80%, which was similar to that of the asphalt mixtures containing slaked lime. In the case of the indirect tensile strength test, the TSR value tends to increase with increasing the air-cooled slag content of the specimens. But the indirect tensile strength was slightly lower in the specimen containing 3% air-cooled slag. The Hamburg wheel tracking test showed that the moisture resistance of the specimens produced in a laboratory and in a plant was good but that of the specimen containing 3% air-cooled slag was slightly lower. The laboratory experiment performed in the present study showed that the moisture resistance was improved by the addition of air-cooled slag, which has a similar composition with slaked lime, to asphalt mixtures. However, when the entire filler of the asphalt mixture was replaced by air-cooled slag, the strength was slightly decreased, indicating that an appropriate amount of air-cooled slag should be added. The applicability of air-cooled slag to asphalt pavement material may need to be studied through a microstructure analysis and a long-term pavement performance test to investigate the mechanism more accurately.


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