scholarly journals Investigation of Moisture Sensitivity and Conductivity Properties of Inductive Asphalt Mixtures Containing Steel Wool Fiber

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Seyed Mohsen Hosseinian ◽  
Vahid Najafi Moghaddam Gilani ◽  
Peyman Mehraban Joobani ◽  
Mahyar Arabani
Keyword(s):  
Electrical Conductivity ◽  
Tensile Strength ◽  
Electrical Resistivity ◽  
Asphalt Mixtures ◽  
Dynamic Resistance ◽  
Moisture Resistance ◽  
Steel Wool ◽  
Moisture Sensitivity ◽  
Optimal Amount ◽  
Marshall Stability

The construction of suitable roads in rainy areas has created problems in the construction process due to the low resistance of asphalt to moisture. To solve this problem, materials are commonly used that make mixtures resistant to moisture; however, these materials may reduce the dynamic resistance of asphalt. Therefore, materials should be used that, in addition to increasing the dynamic resistance, also increase the moisture resistance of asphalt mixtures. One of these materials used in this research is steel wool fiber (SWF), which in addition to creating conductive roads also could have a significant effect on moisture resistance. In this study, the impact of 2%, 4%, 6%, 8%, and 10% SWF on the Marshall stability and moisture sensitivity of mixtures was investigated using the Marshall stability and indirect tensile strength (ITS) tests, respectively. Moreover, using SWF as a conductive fiber, the conductivity properties of asphalt mixtures were explored to find the optimal amount of electrical conductivity. The results of the Marshall stability test indicated that by increasing SWF contents, the stability of mixtures increased, compared with the base sample, and greater amounts of 6% SWF resulted in the reduction of the Marshall stability. The results of ITS showed that modification of bitumen by SWF increased ITS and tensile strength ratio (TSR) amounts of mixtures. 6% SWF was the optimal amount for enhancing the resistance of asphalt mixtures to moisture sensitivity. The results of the electrical resistivity test showed that the resistivity had three phases: high resistivity, transit, and low resistivity. Mixtures containing less than 4% SWF illustrated an insulating behavior, with electrical resistivity greater than 7.62  ×  108  Ω . m . At the transit phase, the resistivity of mixtures had a sharp reduction from 7.62  ×  108  Ω . m to 6.17  ×  104  Ω . m . Finally, 8% SWF was known as the optimal content for the electrical conductivity of mixtures.

scholarly journals Evaluations of Nano-Sized Hydrated Lime on the Moisture Susceptibility of Hot Mix Asphalt Mixtures

2012 ◽  
Vol 174-177 ◽  
pp. 82-90 ◽  
Author(s):  
Ju Nan Shen ◽  
Zhao Xing Xie ◽  
Fei Peng Xiao ◽  
Wen Zhong Fan
Keyword(s):  
Tensile Strength ◽  
Experimental Design ◽  
Hot Mix Asphalt ◽  
Hydrated Lime ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Moisture Resistance ◽  
Strength Ratio ◽  
Moisture Susceptibility ◽  
Indirect Tensile

The objective of this study was to evaluate the effect of nano-sized hydrated lime on the moisture susceptibility of the hot mix asphalt (HMA) mixtures in terms of three methodologies to introduce into the mixtures. The experimental design for this study included the utilizations of one binder source (PG 64-22), three aggregate sources and three different methods introducing the lime. A total of 12 types of HMA mixtures and 72 specimens were fabricated and tested in this study. The performed properties include indirect tensile strength (ITS), tensile strength ratio (TSR), flow, and toughness. The results indicated that the nano-sized lime exhibits better moisture resistance. Introducing process of the nano-sized lime will produce difference in moisture susceptibility.

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
Keyword(s):  
Tensile Strength ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Laboratory Evaluation ◽  
Void Content ◽  
Coarse Aggregates ◽  
Significant Difference ◽  
Indirect Tensile ◽  
Marshall Stability

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.

Evaluation of Moisture Susceptibility of Asphalt Mixtures: Conventional and New Methods

2000 ◽  
Vol 1728 (1) ◽  
pp. 43-51 ◽  
Author(s):  
N. Khosla ◽  
Brian G. Birdsall ◽  
Sachiyo Kawaguchi
Keyword(s):  
Tensile Strength ◽  
Friction Angle ◽  
Hydrated Lime ◽  
Asphalt Mixtures ◽  
Degree Of Saturation ◽  
Phosphate Ester ◽  
Simple Method ◽  
Moisture Sensitivity ◽  
Moisture Susceptibility ◽  
New Apparatus

Evaluation of a mixture’s moisture sensitivity is currently the final step in the Superpave® volumetric process. This step is accomplished by using AASHTO T-283, which tolerates a range of values in the test variables of sample air voids and degree of saturation. The tensile strength ratios determined for the mixes in this study varied with the air void level and degree of saturation. Although the levels of conditioning were within the specifications for AASHTO T-283, test results both passed and failed the 80 percent criterion, depending on the severity of conditioning. An alternative to measuring indirect tensile strength is a test that evaluates a mixture’s fundamental material properties. A relatively simple test is proposed that measures the cohesion and friction angle for asphalt mixtures. In addition, the Superpave shear tester (SST) was incorporated as a tool in evaluating moisture sensitivity. The proposed axial test determined the cohesion and angle of friction of the mix. The friction angle remained constant for the conditioned and unconditioned samples. Hence, conditioning of the samples had practically no effect on the mixture’s internal friction. The cohesion of the mix decreased when the mix was subjected to conditioning. The reduction in cohesion was greater in the case of the Fountain aggregate, which is known to be highly moisture susceptible. The shear tests to failure performed on the SST confirmed the results of the new apparatus, which provides a simple method for determining a mixture’s cohesion. The loss of cohesion due to conditioning can be used to determine a mixture’s moisture susceptibility. The three antistrip additives used in this study were hydrated lime, a liquid amine, and a liquid phosphate ester.

scholarly journals Selecting warm mix asphalt additives by the properties of warm mix asphalt mixtures - China experience

2015 ◽  
Vol 10 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Xinsheng Li ◽  
Zhaoxing Xie ◽  
Wenzhong Fan ◽  
Lili Wang ◽  
Junan Shen
Keyword(s):  
Tensile Strength ◽  
Dynamic Stability ◽  
Asphalt Concrete ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Air Voids ◽  
Mastic Asphalt ◽  
Stone Mastic Asphalt ◽  
Crushed Aggregate ◽  
Marshall Stability

The objective of this research was to select the most effective warm asphalt additives for mix practice based on a series of laboratory testing programs such as density, Marshall stability, freeze-thaw splitting strength, dynamic stability, and bending beam strain. The experimental design of warm mix asphalt included the use of three commonlyused additives, two typical aggregate gradations, one crushed aggregate, and one modified asphalt. Results showed that: (1) the bulk specific gravity and air voids of all the mix specimens were similar to those of controls; (2) the Marshall stability and flow values of the warm stone mastic asphalt were 6.8%–26.6% and 3.5%–10.3%% higher than those of controls, respectively, and those of the warm asphalt concrete were 6.1%–15.6% and 6.5%–9.7% higher than those of controls, respectively; (3) the indirect tensile strength of two types of mixtures was 1.7%–14.4% lower than that of controls, and the average tensile strength ratio of the warm stone mastic asphalt and asphalt concrete was 4.3% and 1.3% higher than that of controls, respectively; (4) the dynamic stability of warm mix specimens was 10.8%–16.6% lower than that of the controls; (5) the average bending failure strain of warm stone mastic asphalt was 7.6% higher than that of the controls, and that of warm asphalt concrete was 12.8% lower than that of the controls; (6) Overall, warm asphalt mixtures with Sasobit and Rediset had relatively best performances required in Southeast China, where rutting and stripping are the main failures of asphalt pavements.

scholarly journals Influence of Natural Fibers on the Performance of Hot Mix Asphalt for the Wearing Course of Pavement

2020 ◽  
Vol 8 (2) ◽  
pp. 57-63
Author(s):  
Omar T. Mahmood ◽  
Sheelan A. Ahmed
Keyword(s):  
Tensile Strength ◽  
Hot Mix Asphalt ◽  
Natural Fiber ◽  
Natural Fibers ◽  
Flexible Pavement ◽  
Asphalt Mixtures ◽  
Palm Fiber ◽  
Marshall Test ◽  
Indirect Tensile ◽  
Marshall Stability

Cracking in the flexible pavement is a serious problem that reduces the service life of the roads pavement unless they are treated with great care. Since flexible pavement is very weaker in tension than in compression, it is usually necessary to consider the tensile stresses and some type of additives to improve asphaltpavement performance, and one of the most effective ways of improving asphalt pavement performance is to reinforce asphalt mixtures by incorporating natural fibers. The main objective of this study is to use palm fiber, which is locally available, in hot mix asphalt mixtures. To achieve this objective, the Marshall test and indirect tensile strength test were conducted on four asphalt mixtures with different types of natural fibers (Coconut, Corn, Palm, and Sisal), added in varying percentages 0.1, 0.2, 0.3, 0.4, and 0.5% and different lengths of fiber 0.5, 1, 1.5, and 2 cm. Based on the analyzed results, it can be concluded that the use of palm fiber increased the Marshall stability by 20% as compared with the conventional mixture and raised up the retained tensile strength ratio up to 92%. Finally, the use of 0.2% content of natural fiber at 1.5 cm length gave a better performance for the mixtures.

Effect of Modified Asphalt Cement of the Performance of Stone Matrix Mixtures

2020 ◽  
Vol 38 (5A) ◽  
pp. 789-800
Author(s):  
Duaa A. Khalaf ◽  
Zaynab I. Qasim ◽  
Karim H. Al Helo
Keyword(s):  
Tensile Strength ◽  
Fracture Resistance ◽  
Laboratory Tests ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Asphalt Cement ◽  
Indirect Tensile ◽  
Marshall Stability ◽  
Stone Matrix

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.

Laboratory Evaluation of Electrically Conductive Asphalt Mixtures for Snow and Ice Removal Applications

2021 ◽  
pp. 036119812199582
Author(s):  
Rahaf Hasan ◽  
Ayman Ali ◽  
Christopher Decarlo ◽  
Mohamed Elshaer ◽  
Yusuf Mehta
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Carbon Fiber ◽  
Asphalt Mixtures ◽  
Laboratory Evaluation ◽  
Particle Sizes ◽  
Rutting Resistance ◽  
Air Voids ◽  
Modified Asphalt ◽  
Performance Grade

The study evaluates the electrical conductivity and mechanical performance of graphite modified asphalt mixtures. The effects of air voids, carbon fiber, and binder performance grade (PG) on the electrical resistivity of graphite modified asphalt mixtures are also assessed. Three graphite grades, two asphalt binders (polymer-modified PG 76-22 and neat PG 64-22), one aggregate type, and one carbon fiber were used to produce graphite modified asphalt mixtures. The mixtures were produced without graphite (control mix, PG 76-22), with only graphite (three grades and PG 76-22), with both graphite and 1% carbon fiber (three grades and PG 76-22), and with graphite (all three grades) and PG 64-22. The electrical conductivity, resistance to rutting, resistance to cracking, and durability of these mixes were evaluated using electrical resistivity (using a multi-meter), asphalt pavement analyzer, Hamburg wheel tracking device, semi-circular bend, indirect tension cracking, and Cantabro loss tests. Test results showed that graphite improves the electrical conductivity of asphalt mixtures when added at dosages of 10% to 15% or higher by volume of binder. Graphite grades with larger particle sizes helped improve the conductivity of asphalt mixtures better than graphite grades with smaller particle sizes. Air voids (higher air voids increased resistivity), carbon fiber dosage (decreased resistivity), and binder performance grade (neat binders had lower resistivity) affected the electrical resistivity of graphite modified asphalt mixtures. Furthermore, graphite modified mixes had better rutting resistance but higher susceptibility to breakdown and cracking when compared with unmodified mixtures.

Evaluation of Moisture Susceptibility of Asphalt Mixtures Containing Bottom Ash

2003 ◽  
Vol 1832 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Menglan Zeng ◽  
Khaled Ksaibati
Keyword(s):  
Tensile Strength ◽  
Power Plants ◽  
Early Stage ◽  
Bottom Ash ◽  
Asphalt Mixtures ◽  
Moisture Resistance ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Dry Conditions ◽  
Lime Addition

Bottom ash, as a by-product of coal-fired electric power plants, has recently been used in constructing transportation facilities. However, the use of bottom ash in asphalt mixtures is still in an early stage. The moisture resistance of asphalt mixtures containing bottom ash, which has not been adequately researched, is investigated in this study. Eight asphalt mixtures produced with one type of asphalt cement, two types of aggregate, three sources of bottom ash, and lime additive were evaluated using the principles in AASHTO T283. Analysis of test data indicated that granite mixtures had higher tensile strength values than did limestone mixtures in dry conditions. Addition of lime or bottom ash did not substantially change these values. All mixtures tested met the Superpave volumetric mix design requirement of tensile strength ratio ( TSR) after one freeze–thaw cycle. The addition of lime significantly improved the moisture resistance of the asphalt mixtures as measured by the TSR. With lime addition, aggregate type, bottom ash addition, and bottom ash source were all insignificant with respect to TSR. On the basis of TSR rate ( TSRR), the addition of lime significantly improved the moisture resistance of the asphalt mixtures subjected to multiple freeze–thaw cycles. Without lime addition, bottom ash played a role similar to that of lime in improving the TSRR for the materials tested.

scholarly journals Laboratory comparative assessment of warm and hot mixes Asphalt containing reclaimed Asphalt pavement

2020 ◽  
Vol 8 (2) ◽  
pp. 15-26
Author(s):  
Hasan H Joni ◽  
Aqeel Y M Alkhafaji
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Reclaimed Asphalt Pavement ◽  
Moisture Resistance ◽  
Recycled Asphalt ◽  
Reclaimed Asphalt ◽  
Marshall Stability ◽  
The Impact

Warm mix Asphalt (WMA) could be mixed and used in paving at low temperatures to minimize the consumption of energy and the emissions of greenhouse gas. Recycled Asphalt pavement (RAP) could save Asphaltic cement and aggregate, which could achieve the better effects of recycling. However, both of the two WMA and RAP technologies have some deficiencies. Warm mix Asphalt and Reclaimed Asphalt pavement (WMA-RAP) technique may solve these issues and deficiencies when they are utilized together. This study investigated the implementations of WMA-RAP and its impacts on the performance of the Asphalt mixture. Under the framework of this study, four percentages of RAP (0%, 20%, 30%, and 40%) were added to the hot mix Asphalt (HMA) and WMA containing 4% Sasobit to study the impact of increasing RAP content on Marshall stability and moisture resistance of Asphalt mixtures. In summary, the Marshall stability of HMA and WMA mixtures is higher than the control mixtures. A small decrease in moisture resistance of both (HMA and WMA) containing RAP comparing to control mixtures Asphalt was observed, as shown by reduced the tensile strength ratios (TSR), but it is still much higher than the minimum of 80%.

scholarly journals Improving the Moisture Sensitivity of Asphalt Mixtures by Simultaneous Modification of Asphalt Binder and Aggregates with Carbon Nanofiber and Carbon Nanotube

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Mohammad Nikookar ◽  
Mojtaba Bagheri Movahhed ◽  
Jalal Ayoubinejad ◽  
Vahid Najafi Moghaddam Gilani ◽  
Seyed Mohsen Hosseinian
Keyword(s):  
Tensile Strength ◽  
Free Energy ◽  
Carbon Nanotube ◽  
Carbon Nanofiber ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Moisture Sensitivity ◽  
Tensile Strength Test ◽  
Indirect Tensile

Moisture sensitivity of asphalt mixtures may cause damage due to cohesion in asphalt binder membrane and adhesion between aggregate and asphalt binder that result in considerable damage to the pavements. Therefore, by determining the adhesion quality in a modified aggregate-asphalt binder system, one can choose the suitable material compositions to decrease the moisture sensitivity of mixtures. In this study, the effects of modified asphalt binder with carbon nanofiber and modified aggregates with carbon nanotube on the moisture sensitivity of asphalt mixtures were simultaneously explored. For investigating the moisture sensitivity, the indirect tensile strength test and surface free energy concept were implemented. The results of the indirect tensile strength test revealed that modification of asphalt binder and aggregates with carbon nanofiber and carbon nanotube, respectively, increased the indirect tensile strength and tensile strength ratio values of mixtures. The results of surface free energy indicated that using carbon nanofiber and carbon nanotube enhanced the adhesion free energy of the aggregate-asphalt binder system. Moreover, utilizing carbon nanofiber to modify asphalt binder enhanced the cohesion free energy values in the asphalt binder membrane. Also, carbon nanofiber and carbon nanotube brought detachment energy of the system toward zero, indicating less desire for the mixtures to be stripped. Generally, investigations performed by the two methods showed that covering aggregates by carbon nanotube as well as utilizing carbon nanofiber as an asphalt binder modifier had a positive impact on decreasing moisture sensitivity of asphalt mixtures.

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