Evaluation of the Gradation Effect on the Dynamic Modulus

2005 ◽  
Vol 1929 (1) ◽  
pp. 193-199 ◽  
Author(s):  
Bjorn Birgisson ◽  
Reynaldo Roque
Keyword(s):  
Power Law ◽  
Dynamic Modulus ◽  
Asphalt Mixture ◽  
Design Procedure ◽  
Maximum Size ◽  
Pavement Design ◽  
Aggregate Gradation ◽  
Higher Temperature ◽  
Power Law Parameters ◽  
Selection Of

The importance of aggregate characteristics has been emphasized in the Superpave® asphalt mixture design procedure. However, criteria for guidelines for the selection of suitable aggregate gradations–-other than gradation limits for different nominal maximum size aggregate blends, including the restricted zone–-have been neglected. With the move toward mechanistic–empirical pavement design, the dynamic modulus is used to account for mixture properties in the pavement design. It is of significant importance to mix designers to possess a framework for determining how to optimize a mixture for ensuring an adequate dynamic modulus. This paper presents the results from a study of the effects of gradation characteristics on the dynamic modulus. Power law–based gradation factors are obtained for 13 aggregate gradations (coarse and fine graded) composed of limestone and granite aggregates. These gradation factors were used to identify and evaluate relationships between gradation factors and the dynamic modulus at higher temperature (40°C). Subsequently, a tentative framework was established for optimizing mixture gradations for dynamic modulus values. Findings illustrate that gradation factors based on power law parameters can be used to optimize mixture gradations for key mixture properties, such as the dynamic modulus. Results also demonstrate the critical nature of aggregate gradation in achieving desired mixture properties.

Study on Flexible Base Asphalt Pavement Design System Based on the Dynamic Modulus

2013 ◽  
Vol 788 ◽  
pp. 619-622
Author(s):  
Li Yin
Keyword(s):  
Mechanical Properties ◽  
Dynamic Modulus ◽  
Design Method ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Pavement Design ◽  
Pavement Performance ◽  
Design System ◽  
Determination Method ◽  
Flexible Base

Pavement design adopts the static index pavement design method; it has significant limitations for flexible asphalt pavement. This paper proposes asphalt mixture dynamic modulus determination method on the basis of existing research results at home and abroad. Dynamic modulus effect is studied on the mechanical properties of flexible base asphalt pavement, and the flexible base asphalt pavement performance is preestimated by the use of the dynamic modulus indicators in the paper.

scholarly journals Dynamic Modulus of Porous Asphalt and the Effect of Moisture Conditioning

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1230 ◽  
Author(s):  
Tan Hung Nguyen ◽  
Jaehun Ahn ◽  
Jaejun Lee ◽  
Jin-Hwan Kim
Keyword(s):  
Dynamic Modulus ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Void Content ◽  
Water Tank ◽  
Porous Asphalt ◽  
Air Void ◽  
Frequent Exposure ◽  
Air Void Content ◽  
Selection Of

Porous asphalt has been used for permeable pavement to improve safety of roadways and the effectiveness of storm water management. As a surface drainage layer with frequent exposure to water, this material is affected by moisture. In this study, dynamic modulus tests were performed on both moisture unconditioned and conditioned specimens to characterize viscoelastic properties of porous asphalt mixture. The dynamic modulus values of porous asphalt materials with air void content of 9.0% and 20.5% were investigated at dry condition and after specified moisture conditioning cycles. One cycle of moisture conditioning procedure included placing specimens in water tank at 60 °C for 24 h, and then in another water tank at 25 °C for additional 2 h. The results showed that porous asphalt mixture with lower air void content resulted in higher values of dynamic modulus, and these values of porous asphalt with air void content of 9.0% was about 1.5 to 3.0 times that of porous asphalt with air void content of 20.5%. Higher value of the first number of performance graded binder (average 7-day maximum pavement design temperature) seems to make the dynamic modulus values at high temperatures larger. After moisture conditioning, the dynamic modulus of porous asphalt mixture increased, overall, especially at low temperatures. The appropriated selection of asphalt binder, a weakening of asphalt due to moisture damage can be reduced.

Effect of Asphalt Mixture Components on the Uncertainty in Dynamic Modulus Mastercurves

2020 ◽  
Vol 2674 (5) ◽  
pp. 135-148
Author(s):  
Hussein Kassem ◽  
Ghassan Chehab ◽  
Shadi Najjar
Keyword(s):  
Dynamic Modulus ◽  
Asphalt Mixture ◽  
Fundamental Property ◽  
Aggregate Size ◽  
Pavement Design ◽  
Experimental Program ◽  
Maximum Aggregate Size ◽  
Pavement Materials ◽  
Material Sources ◽  
Key Factor

Practitioners and researchers in the paving industry have highlighted the importance of the adoption of reliability-based pavement design. The goal of developing reliable pavements with optimum performance over their design life has become a key factor to be considered during both pavement design and construction processes. This requires the adoption of statistical and probabilistic-based analyses for the formulation of the properties and behavior of pavement materials. Thus, many researchers worked on the quantification and modeling of the uncertainty caused by the inherent variability in pavement materials in general and that of asphalt concrete (AC) in particular. The dynamic modulus (| E*|), a fundamental property for mechanistic-empirical and purely mechanistic pavement designs, has been proven to have a significant level of uncertainty that is dependent on climatic and traffic loading conditions. The main objective of this study is to investigate the effect of the AC mixture properties and components on the uncertainty in the | E*| mastercurve. This objective is achieved by conducting an experimental program incorporating four different mixtures having the same material sources but different binder types and gradations. Monte Carlo simulations are used to model the uncertainty of | E*| for each of these mixtures. The paper shows that the uncertainty is dependent on mixture type, as the presence of larger nominal maximum aggregate size, modified binder, or additive can increase the uncertainty in the | E*| mastercurve, especially at high temperatures or slow loading rates. The uncertainty is proven to be material related and not imposed by the testing instrumentation.

Development of a Performance-Related Framework for Asphalt Mixture Design for the Illinois Tollway

2021 ◽  
pp. 036119812110148
Author(s):  
Behnam Jahangiri ◽  
Punyaslok Rath ◽  
Hamed Majidifard ◽  
William G. Buttlar
Keyword(s):  
Asphalt Mixture ◽  
Field Performance ◽  
Compact Tension ◽  
T Test ◽  
Novel Approach ◽  
Final Adjustment ◽  
Development And Validation ◽  
High Degree ◽  
Selection Of

Various agencies have begun to research and introduce performance-related specifications (PRS) for the design of modern asphalt paving mixtures. The focus of most recent studies has been directed toward simplified cracking test development and evaluation. In some cases, development and validation of PRS has been performed, building on these new tests, often by comparison of test values to accelerated pavement test studies and/or to limited field data. This study describes the findings of a comprehensive research project conducted at Illinois Tollway, leading to a PRS for the design of mainline and shoulder asphalt mixtures. A novel approach was developed, involving the systematic establishment of specification requirements based on: 1) selection of baseline values based on minimally acceptable field performance thresholds; 2) elevation of thresholds to account for differences between short-term lab aging and expected long-term field aging; 3) further elevation of thresholds to account for variability in lab testing, plus variability in the testing of field cores; and 4) final adjustment and rounding of thresholds based on a consensus process. After a thorough evaluation of different candidate cracking tests in the course of the project, the Disk-shaped Compact Tension—DC(T)—test was chosen to be retained in the Illinois Tollway PRS and to be presented in this study for the design of crack-resistant mixtures. The DC(T) test was selected because of its high degree of correlation with field results and its excellent repeatability. Tailored Hamburg rut depth and stripping inflection point thresholds were also established for mainline and shoulder mixes.

scholarly journals Laboratory Investigation of Compaction Characteristics of Plant Recycled Hot-Mix Asphalt Mixture

2021 ◽  
Vol 13 (6) ◽  
pp. 3005
Author(s):  
Jiangang Yang ◽  
Chen Sun ◽  
Wenjie Tao ◽  
Jie Gao ◽  
Bocheng Huang ◽  
...  
Keyword(s):  
Regression Model ◽  
Hot Mix Asphalt ◽  
Orthogonal Experiment ◽  
Asphalt Mixture ◽  
Material Design ◽  
Void Content ◽  
Range Analysis ◽  
Aggregate Gradation ◽  
Compaction Characteristics ◽  
Compaction Energy

In this study, the compaction characteristics of recycled hot-mix asphalt (RHMA) were evaluated using the void content (VV), compaction energy index (CEI), slope of accumulated compaction energy (K), and lock point (LP). Then, the effects of the compaction parameters, including the gradation of the RHMA, reclaimed asphalt pavement (RAP) content, temperature of gyrations, and number of gyrations, on the compaction characteristics of RHMA were investigated. An orthogonal experiment was designed and the data collected were analyzed via range analysis; then, a regression model was generated relying on a quadratic polynomial. Furthermore, the regression model was used for the comparison and prediction of the mixture’s compactability during the material design. Finally, the compaction mechanism of RHMA was discussed from the perspective of the void content of RAP particles. The results showed that a finer aggregate gradation, a higher gyration temperature, a greater number of gyrations, and a higher RAP content were effective for increasing the compactability of RHMA. The range analysis results suggest that the gradation of RHMA has the greatest influence on compactability, followed by the RAP content. The RAP aggregate cannot diffuse to a new mixture completely, so the remained RAP particle reduces the void content of RHMA. Therefore, a higher RAP content up to 50% can help RHMA to achieve the designed void content with higher efficiency.

scholarly journals Power-law bounds for critical long-range percolation below the upper-critical dimension

2021 ◽  
Author(s):  
Tom Hutchcroft
Keyword(s):  
Long Range ◽  
Power Law ◽  
Upper Bound ◽  
Mean Field ◽  
Maximum Size ◽  
Finite Graph ◽  
Critical Dimension ◽  
Point Function ◽  
Upper Critical Dimension ◽  
Infinite Cluster

AbstractWe study long-range Bernoulli percolation on $${\mathbb {Z}}^d$$ Z d in which each two vertices x and y are connected by an edge with probability $$1-\exp (-\beta \Vert x-y\Vert ^{-d-\alpha })$$ 1 - exp ( - β ‖ x - y ‖ - d - α ) . It is a theorem of Noam Berger (Commun. Math. Phys., 2002) that if $$0<\alpha <d$$ 0 < α < d then there is no infinite cluster at the critical parameter $$\beta _c$$ β c . We give a new, quantitative proof of this theorem establishing the power-law upper bound $$\begin{aligned} {\mathbf {P}}_{\beta _c}\bigl (|K|\ge n\bigr ) \le C n^{-(d-\alpha )/(2d+\alpha )} \end{aligned}$$ P β c ( | K | ≥ n ) ≤ C n - ( d - α ) / ( 2 d + α ) for every $$n\ge 1$$ n ≥ 1 , where K is the cluster of the origin. We believe that this is the first rigorous power-law upper bound for a Bernoulli percolation model that is neither planar nor expected to exhibit mean-field critical behaviour. As part of the proof, we establish a universal inequality implying that the maximum size of a cluster in percolation on any finite graph is of the same order as its mean with high probability. We apply this inequality to derive a new rigorous hyperscaling inequality $$(2-\eta )(\delta +1)\le d(\delta -1)$$ ( 2 - η ) ( δ + 1 ) ≤ d ( δ - 1 ) relating the cluster-volume exponent $$\delta $$ δ and two-point function exponent $$\eta $$ η .

Palm Kernel Shell as Partial Coarse Aggregate Replacement in Asphalt Mixture: Optimum Binder Content and Volumetric Properties Investigation

2021 ◽  
Vol 1047 ◽  
pp. 179-185
Author(s):  
Siti Zubaidah Mohd Asri ◽  
Faridah Hanim Khairuddin ◽  
Choy Peng Ng ◽  
Noor Aina Misnon ◽  
Nur Izzi Md Yusoff ◽  
...  
Keyword(s):  
Coarse Aggregate ◽  
Asphalt Mixture ◽  
Control Sample ◽  
Palm Kernel ◽  
Binder Content ◽  
Partial Replacement ◽  
Volumetric Properties ◽  
Aggregate Gradation ◽  
Palm Kernel Shell ◽  
Mixture Samples

Pavement failures such as fatigue, rutting, cracking, bleeding, and stripping are typical pavement deterioration. Researchers have been experimenting with pavement modification to overcome these problems. This study determines the optimum binder content (OBC) for modifying an asphalt mixture with a partial replacement of coarse aggregate (5mm-14mm sieve size) with palm kernel shell (PKS). A 60/70 penetration grade bitumen was mixed with 10, 20 and 30% PKS at selected aggregate gradation following the Public Work Department of Malaysia (JKR/SPJ/2008-S4) specification. The preparation of 60 samples of unmodified and modified asphalt mixture employed the Marshall Method compacted with 75 blows. The OBC was determined based on five volumetric properties of asphalt mixture namely stability, flow, bulk density, void filled with asphalt, and void in total mix. The OBC and volumetric properties of the modified PKS asphalt mixture samples were compared with unmodified asphalt mixture samples in accordance to the specification. Results showed that the OBC sample with 30% aggregate replacement produced the highest OBC value of 5.53% relative to the control sample with 5.40% OBC. The trend for OBC with PKS replacement begins with 10% PKS with 5.30% OBC, 20% PKS with 5.32% OBC and 30% PKS. All volumetric properties of the PKS samples are within the specification limit. Thus, PKS has a promising potential as a coarse aggregate replacement in asphalt mixture.

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