Considerations for Design of Aggregate Gradation in Pavement Drainage Layers

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.

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Evaluation of Bleeding Resistance in Chip Seal and Asphalt Emulsion Residue Rheology

Coatings ◽

10.3390/coatings9100670 ◽

2019 ◽

Vol 9 (10) ◽

pp. 670

Author(s):

Preeda Chaturabong

Keyword(s):

Influence Factors ◽

Application Rate ◽

Test Methods ◽

Test Results ◽

Asphalt Emulsion ◽

Aggregate Gradation ◽

Factors Affecting ◽

Promising Tool ◽

Chip Seal ◽

Asphalt Emulsions

Chip seal bleeding is influenced by many factors, including design inputs, material properties, and project-specific conditions. It reduces the surface texture of the pavement and thus compromises the safety of the traveling public. Even though factors that bring about premature bleeding are known, currently, no laboratory test methods for evaluating bleeding in chip seals have been specified. The objective of this paper is to present the results of an investigation of the influence factors of asphalt emulsion residue properties measured by the ASTM D7405 multiple stress creep and recovery (MSCR) test, as well as other factors related to chip seal bleeding resistance as measured by the modified loaded wheel test (MLWT). In this study, the MSCR test was used as a tool for evaluating the performance of asphalt emulsions because it has been identified as a potential test related to bleeding in the field. In addition, MLWT was selected as a tool for evaluating chip seal bleeding performance in the laboratory. The results of the MLWT showed that the emulsion application rate (EAR), aggregate gradation, and emulsion properties were significant factors affecting bleeding. The MSCR test was found to be a promising tool for the performance evaluation of asphalt emulsion residue, as the test was able to differentiate between emulsion chemistries and modifications in terms of sensitivity to both temperature and stress. In relation to chip seal bleeding resistance, only the creep compliance (Jnr) obtained from the MSCR test results was identified as a significant property affecting potential for bleeding.

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Numerical Investigation on Shear Failure of Concrete Beam Strengthened by Bonded Steel Plate

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.351-352.1552 ◽

2013 ◽

Vol 351-352 ◽

pp. 1552-1557

Author(s):

Da Guo Wang ◽

Zhi Xiu Wang ◽

Bing Xu

Keyword(s):

Numerical Investigation ◽

Concrete Beam ◽

Shear Failure ◽

Steel Plate ◽

Damage Model ◽

Adhesive Layer ◽

Aggregate Gradation ◽

Brittle Damage ◽

Plastic Yield ◽

Final Failure

Based on micromechanics, an elastic-plastic-brittle damage model of concrete beam reinforced with stick steel is proposed by considering the aggregate gradation curve algorithms and the heterogeneity. In the model, the concrete beam reinforced with stick steel is taken as a five-phase composite material that consists of the mortar matrix, coarse aggregate, bonds between mortar and aggregate, steel plate, and the adhesive layer between steel plate and concrete beam. Through the numerical investigation on shear failure of concrete beam reinforced with stick steel under external force, the results show that the model can clearly simulate microscopic plastic yield, and the initiation and extension of crack. The strength of the steel plate is relatively stronger, so it cant enhance the shear capability of the each side of the beam and the concrete beam bears the larger shear stress, which results that a large number of elements, from the supports to the load points, begin to yield. When the strain of the elements exceeds the yield strength, the elements will produce failure until the failure of the whole specimen. The final failure mode of concrete beam reinforced with stick steel is the shear failure.

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Effect of aggregate gradation on the cracking performance of wearing course mixtures

Construction and Building Materials ◽

10.1016/j.conbuildmat.2017.07.009 ◽

2017 ◽

Vol 152 ◽

pp. 520-528 ◽

Cited By ~ 4

Author(s):

Nhat Thanh Tran ◽

Osamu Takahashi

Keyword(s):

Aggregate Gradation ◽

Cracking Performance

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2D Image based sieving for particle aggregate gradation

Journal of Electronics (China) ◽

10.1007/s11767-007-0123-z ◽

2008 ◽

Vol 25 (2) ◽

pp. 277-282 ◽

Cited By ~ 1

Author(s):

Chen Ken ◽

John Zaniewski ◽

Pan Zhao ◽

Ren’er Yang

Keyword(s):

Aggregate Gradation ◽

Particle Aggregate

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1047.179 ◽

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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