scholarly journals An investigation on the effects of flaky particles on the properties of asphaltic mixtures

2015 ◽  
Vol 42 (11) ◽  
pp. 865-871 ◽  
Author(s):  
Babak Kazemi Darabadi ◽  
Hasan Taherkhani
Keyword(s):  
Creep Behaviour ◽  
Permanent Deformation ◽  
Asphaltic Concrete ◽  
Test Results ◽  
Creep Tests ◽  
Air Voids ◽  
Static Creep ◽  
Different Types ◽  
Creep Stiffness ◽  
Marshall Stability

Flaky particles, because of their shape, are considered as inferior aggregates in asphaltic mixtures, and specifications usually set limits on the amount of flaky particles in asphaltic mixtures. In this study, the effects of flaky particles content on the volumetric properties, Marshall Stability and creep behaviour of hot mixed asphaltic concrete have been investigated. Specimens with two different types of gradation and specified amounts of flaky particles were made and used for Marshall Stability and static creep tests. Test results show that the Marshall Stability decreases and the air voids content of asphaltic mixture and the voids in mineral aggregate increase as the flaky particles content increases. It is also found that flaky particles cause increase in permanent deformation and decrease in creep stiffness. The creep tests also show that the recoverable deformation of the mixtures decreases as the flaky particles content increases.

Laboratory Investigate of the Effect of Fine Aggregates on Asphalt Mixture Materials

2011 ◽  
Vol 225-226 ◽  
pp. 577-580
Author(s):  
Yong Ye ◽  
Yi Zhou Cai
Keyword(s):  
Compressive Strength ◽  
Asphalt Mixture ◽  
Aggregate Size ◽  
Asphalt Mixtures ◽  
Fine Aggregate ◽  
Test Results ◽  
Creep Tests ◽  
Aggregate Gradation ◽  
Static Creep ◽  
Fine Aggregates

The objective of this study is to investigate and evaluate the effect of fine aggregates (aggregate size smaller than or equal to 2.36 mm) on the compressive strength and creep behavior of asphalt mixtures. The variables that are considered in the study include the sizes and gradations of fine aggregate. A kind of standant aggregate gradation and four kinds of reduced aggregate gradation mixture specimens are used. Uniaxial compression and static creep tests were realized at different loading conditions. The test results showed that the different fine aggregate sizes do not result in significant differences in compressive strength and creep values using the same percentage of fine aggregates (38.4%). Only the different gradations showed a little differences for mixtures made with different gradations but same aggregate size (between 2.36 and 1.18 mm).

scholarly journals Coal Bottom Ash as Partial Replacement of Fine Aggregate in Asphaltic Concrete

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
H. Mohammed
Keyword(s):  
Fixed Bed ◽  
Bottom Ash ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Asphaltic Concrete ◽  
Air Voids ◽  
Coal Bottom Ash ◽  
Asphalt Mix ◽  
Materials Used ◽  
Marshall Stability

The effect of coal bottom ash (CBA) on the characteristics of asphaltic concrete was investigated with a view to assess its suitability as a partial replacement of fine aggregate. Coal procured from Lafia-Obi coal mines was burnt in a fixed bed combustor until a sand size residual was produced. The properties of the materials used for the study were characterize using standard procedures. The CBA was introduced in the asphalt mix at an increasing rate of 10, 15, 20 and 25% content by weight of the fine aggregate and test samples of asphaltic concrete were prepared. The samples were subjected to Marshall stability test. Results showed that the specific gravity and absorption test for granite dust were 2.45 and 0.25%, respectively, while those of the CBA were 2.86 and 0.58% respectively. The result of stability, flow, bulk density, voids filled in bitumen (VFB), air voids (VA) and voids in mineral aggregate (VMA) of the asphaltic concrete at 0% CBA were 12.02 kN, 3.04 mm, 2.491g/cm3, 66.0%, 4.3%, 12.7% respectively; while the values at 20% CBA content were 16.97 kN, 3.51mm, 2.514g/ cm3 , 71.2%, 3.4%, 11.9% respectively. The result showed that coal bottom ash in asphaltic mix improved its properties.

Modeling of Polypropylene Modified Bitumen Mix Design Results Using Regression Analysis

2017 ◽  
pp. 256-275
Author(s):  
Kaval Chhabra ◽  
Divesh Agrawal ◽  
Saladi S. V. Subbarao
Keyword(s):  
Unit Weight ◽  
Waste Plastics ◽  
Test Results ◽  
Modified Bitumen ◽  
Modeling Framework ◽  
Air Voids ◽  
Marshall Test ◽  
Input Variables ◽  
Marshall Stability ◽  
Plastic Content

This study investigates the effects of mixing Polypropylene waste plastics in the bituminous mix for the design of Flexible Pavement. Since, obtaining Marshall Test results from the bituminous mix is time-consuming, so if the practitioners measure the values of stability and flow by mechanical testing, other computations can be done by applying simple mathematical calculations. So, this study carried out stability and flow tests on different specimens made with varying bitumen and polypropylene plastic content. From the initial test results, the optimum bitumen and plastic contents are found. Further, the test results obtained from Marshall Test are modelled by identifying various input variables, which are various physical properties of the mix such as plastic content, bitumen content, air voids and unit weight. The regression modeling framework is adopted in this study to predict the Marshall stability and flow value. Since the developed models have yielded good results, these can be effectively used in parameter estimation, and thus aids the future researchers.

scholarly journals Application of WMA Technology to Bituminous Base Course Mixes

2018 ◽  
Vol 13 (2) ◽  
pp. 94-103 ◽  
Author(s):  
Rajan Choudhary ◽  
Asho Julaganti ◽  
Abhinay Kumar ◽  
Dipak Arjun Ugale
Keyword(s):  
Hot Mix Asphalt ◽  
Permanent Deformation ◽  
Warm Mix Asphalt ◽  
Strength Ratio ◽  
Test Results ◽  
Base Course ◽  
Marshall Stability ◽  
Rheological Test ◽  
Stability Results ◽  
Different Doses

Warm Mix Asphalt, due to lower mixing and compaction temperatures, provides some engineering benefits over conventional Hot Mix Asphalt. In this study, an attempt is made to assess the viability of using Warm Mix Asphalt technology in bituminous base courses. An organic wax-based Warm Mix Asphalt additive was used in this study to produce Dense Bituminous Macadam, a commonly used bituminous base course mix in India. Experimental variables included three additive contents and four mixing temperatures. Rheological properties of binder modified with different doses of additive were examined. In all, twelve Warm Mix Asphalt Dense Bituminous Macadam mix types were prepared, evaluated and compared with Hot Mix Asphalt Dense Bituminous Macadam (control) mix. Rheological test results showed the addition of wax-based additive improved stiffness and resistance against permanent deformation of the base binder. Tensile Strength Ratio and retained Marshall Stability results indicated that Warm Mix Asphalt Dense Bituminous Macadam mixes were resistant to moisture-induced damage.

scholarly journals Effects of Carbon Fibre on Performance Properties of Asphalt Mixtures

2020 ◽  
Vol 15 (2) ◽  
pp. 49-65 ◽  
Author(s):  
Tacettin Geckil ◽  
Perviz Ahmedzade
Keyword(s):  
Carbon Fibre ◽  
Permanent Deformation ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Positive Contribution ◽  
Stiffness Modulus ◽  
Performance Properties ◽  
Creep Stiffness ◽  
Indirect Tensile ◽  
Marshall Stability

In this study, the effects of carbon fibre on improving the performance characteristics of asphalt mixtures were investigated. To this end, four percentages of carbon fibre (0%, 0.3%, 0.5%, and 0.7% by weight of bitumen) were used as an additive in asphalt mixtures. The mechanical properties of prepared mixture specimens were investigated using tests such as Marshall Stability and flow, Indirect Tensile Stiffness Modulus, Creep Stiffness, Indirect Tensile Strength, and moisture resistance. The results of tests applied to asphalt mixtures showed that the carbon fibre additive increased the resistance to shear stress by 25%, the fatigue life by 51% at 40 °C and the permanent deformation resistance by 2.25 times at 60 °C. It also improved the resistance of mixtures to moisture damage by increasing the durability and cohesion of asphalt mixtures. Experimental results indicated that the carbon fibre provided a positive contribution to the performance properties of asphalt pavements.

Modeling of Polypropylene Modified Bitumen Mix Design Results Using Regression Analysis

2020 ◽  
pp. 1644-1663
Author(s):  
Kaval Chhabra ◽  
Divesh Agrawal ◽  
Saladi S. V. Subbarao
Keyword(s):  
Unit Weight ◽  
Waste Plastics ◽  
Test Results ◽  
Modified Bitumen ◽  
Modeling Framework ◽  
Air Voids ◽  
Marshall Test ◽  
Input Variables ◽  
Marshall Stability ◽  
Plastic Content

This study investigates the effects of mixing Polypropylene waste plastics in the bituminous mix for the design of Flexible Pavement. Since, obtaining Marshall Test results from the bituminous mix is time-consuming, so if the practitioners measure the values of stability and flow by mechanical testing, other computations can be done by applying simple mathematical calculations. So, this study carried out stability and flow tests on different specimens made with varying bitumen and polypropylene plastic content. From the initial test results, the optimum bitumen and plastic contents are found. Further, the test results obtained from Marshall Test are modelled by identifying various input variables, which are various physical properties of the mix such as plastic content, bitumen content, air voids and unit weight. The regression modeling framework is adopted in this study to predict the Marshall stability and flow value. Since the developed models have yielded good results, these can be effectively used in parameter estimation, and thus aids the future researchers.

scholarly journals The Relationship between the Air Content in the Mortar and Concrete for Different Types of Cement

2019 ◽  
Author(s):  
Beata Łaźniewska-Piekar ◽  
Jacek Gołaszewski
Keyword(s):  
Cement Paste ◽  
Air Entrainment ◽  
Hardened Concrete ◽  
Test Results ◽  
Air Voids ◽  
Air Content ◽  
Air Volume ◽  
Spacing Factor ◽  
Different Types ◽  
The Relationship

Research results of the relationships between air-volume in air-entrained cement paste, mortar and concrete, all designed according to PN-EN 480-1 guidelines are presented in the paper. The cement paste, mortar and concrete, with w/c=0,5 ratio, were prepared using innovative air-entraining cement CEM II/B-V. The air-entraining cement CEM II/B-V was produced using two methods: mixed together with natural or synthetic aerated admixture. The air volume test of the volumetric method was carried out in case of fresh cement paste, mortar and concrete mix. Fresh concretes were evaluated in terms of stability of air entrainment and consistency for 5, 20 and 40 min. The porosity structure parameters, like summarized air-content, specific surface of air voids, air-voids spacing factor and micropores content of hardened concrete, were estimated using computed tomography with a resolution of 2-5 μm. The aim of the research was to determine the dependence between air-content of cement paste, mortar and concrete on the measurement of air-entrainment of cement paste or mortar with the same w/c ratio and type of cement, all designed according to PN-EN 480-1 guidelines. Test results proved that there is a good correlation between the measured air-content of the cement paste, mortar and concrete. Therefore, it is possible to predict the aeration of concrete on the air-entrainment of the mortar.

scholarly journals Study on Creep Behavior Of Asphalt Mixture Based on Discrete Element Method

2020 ◽  
Vol 15 (4) ◽  
pp. 174-195
Author(s):  
Youlin Ye ◽  
Yazhen Sun ◽  
Lin Gao ◽  
Zhuang Ma ◽  
Xingwei Xue
Keyword(s):  
Uniaxial Compression ◽  
Creep Behaviour ◽  
Viscoelastic Model ◽  
Asphalt Mixture ◽  
Discrete Element ◽  
Creep Tests ◽  
Burger Model ◽  
Air Voids ◽  
Compression Creep ◽  
Asphalt Mortar

A three-dimensional (3D) microstructure-based discrete element (DE) model was developed to study the creep behaviour of high viscoelastic asphalt sand (HVAS) with the uniaxial compression creep tests. The three-point bending creep tests of asphalt mortar were carried out in order to obtain the parameters of the Burger model, to determine the transformation method of macroscopic parameters and microscopic parameters of the model in theory, to obtain the parameters used in the discrete element model, and then establish the discrete element analysis model for the asphalt mixture. A 3D-DE digital specimen was composed of coarse aggregates, asphalt mortar and air voids, which could also take gradation, irregular shape, random distribution of aggregate and air voids into consideration, and the boundary conditions of the model were set through the simulation of the uniaxial compression creep tests. An accurate and extensive mapping model of HVAS was built by 3D-PFC (Particle Flow Code), which can provide a simple alternative to the laboratory tests. This method can simulate a series of numerical examples based on different stress levels, coarse aggregate homogenizations, mortar homogenizations and temperatures in a single factor method. Comparison of results of laboratory and numerical tests shows that the 3D-PFC-viscoelastic model can reflect the creep mechanical behaviour of asphalt mixture accurately. It provides the theoretical basis and auxiliary means for analysing the mechanical properties of asphalt mixtures using PFC software. The research on creep behaviour of the asphalt mixture by numerical simulation opens up a new way for the research on creep behaviour of the asphalt mixture, it is of considerable theoretical value and has broad application prospects.

scholarly journals Sensitivity of the Flow Number to Mix Factors of Hot-Mix Asphalt

2019 ◽  
Vol 4 (2) ◽  
pp. 34 ◽  
Author(s):  
Md Rashadul Islam ◽  
Sylvester A. Kalevela ◽  
Shelby K. Nesselhauf
Keyword(s):  
Hot Mix Asphalt ◽  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Flexible Pavement ◽  
Binder Content ◽  
Flow Number ◽  
Air Voids ◽  
Different Types ◽  
Asphalt Content ◽  
Mineral Aggregates

In the design of pavement infrastructure, the flow number is used to determine the suitability of a hot-mix asphalt mixture (HMA) to resist permanent deformation when used in flexible pavement. This study investigates the sensitivity of the flow numbers to the mix factors of eleven categories of HMAs used in flexible pavements. A total of 105 specimens were studied for these eleven categories of HMAs. For each category of asphalt mixture, the variations in flow number for different contractors, binder types, effective binder contents, air voids, voids in mineral aggregates, voids filled with asphalt, and asphalt contents were assessed statistically. The results show that the flow numbers for different types of HMA used in Colorado vary from 47 to 2272. The same mix may have statistically different flow numbers, regardless of the contractor. The flow number increases with increasing effective binder content, air voids, voids in mineral aggregates, voids filled with asphalt, and asphalt content in the study range of these parameters.

The Effect of Coarse Aggregate Gradation Degradation on the Mechanical Behavior of Asphalt Mixture

2013 ◽  
Vol 811 ◽  
pp. 223-227
Author(s):  
Yong Ye ◽  
Hong Kai Chen ◽  
Yi Zhou Cai
Keyword(s):  
Compressive Strength ◽  
Creep Behavior ◽  
Coarse Aggregate ◽  
Asphalt Mixture ◽  
Aggregate Size ◽  
Test Results ◽  
Creep Tests ◽  
Aggregate Gradation ◽  
Coarse Aggregates ◽  
Static Creep

The objective of this study is to investigate and evaluate the effect of coarse aggregates (aggregate size bigger than 2.36 mm) on the compressive strength and creep behavior of asphalt mixture. The variable that is mainly considered in the study is the gradation degradation of coarse aggregates. A kind of standard aggregate gradation and three kinds of degraded aggregate gradation mixture specimens are used. Uniaxial compression and static creep tests were realized at different loading conditions and temperatures. The test results on asphalt mixture showed that the compressive strength and creep behavior of asphalt mixture are significant affected by the different coarse aggregate gradations.

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