Journal articles: 'Nominal Maximum Aggregate Size'

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Zhang, Chen Chen, Guang Yang, Li Jia Zhou, and Jing Hang Wu. "Fine Aggregate Interference on Thermal Stability of Asphalt Mixture." Applied Mechanics and Materials 470 (December 2013): 823–26. http://dx.doi.org/10.4028/www.scientific.net/amm.470.823.

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Fine aggregates are sensitive parts to skeleton structure of mixture and decrease rutting resistance of asphalt mixtures. In order to evaluate the high temperature performance of mixtures with different fine aggregate (2.36mm and 1.18mm) content, 16 gradations were investigated. Flow number test and rutting test was conducted to evaluate anti-rutting performance of mixtures. Then, interference coefficient was put forward to analyze interference rule of high temperature performance. The results show that high temperature performance was improved with the increasing size of nominal maximum aggregate size; the interference effects of fine aggregate ( 2.36mm and 1.18 mm ) is inversely proportional to nominal maximum aggregate size.

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Garcia-Gil, Lívia, Rodrigo Miró, and Félix Pérez-Jiménez. "Evaluating the Role of Aggregate Gradation on Cracking Performance of Asphalt Concrete for Thin Overlays." Applied Sciences 9, no. 4 (February 13, 2019): 628. http://dx.doi.org/10.3390/app9040628.

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Thin asphalt concrete overlays are a maintenance technique that mainly restore the functional properties of pavements. One of the main issues in thin overlays is reflective cracking that can cause early deterioration and reduce their service life. For this reason, the purpose of this investigation is to evaluate the effect of material selection on cracking performance of asphalt concrete mixtures for thin overlays. In particular, this paper evaluates the role of aggregate skeleton gradation. The study of the effect of aggregate gradation was divided into two stages: (1) fine fraction content and (2) maximum nominal aggregate size. Based on this, up to seven asphalt mixture gradations were designed and evaluated through the Fénix test at different test temperatures. The results showed a significant correlation between the fine fraction content, and maximum nominal aggregate size, and the cracking performance of the asphalt concrete mixtures. Mixtures manufactured with a low content of fine aggregates, as well as small nominal maximum size, experienced a further improvement of their toughness. These results reflected the importance of considering not only the effect of asphalt binder and environmental conditions but also aggregate gradation in the design of asphalt concrete mixtures in order to achieve a desirable cracking performance.

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Huang, Wenke, Xu Cai, Xiang Li, Wentian Cui, and Kuanghuai Wu. "Influence of Nominal Maximum Aggregate Size and Aggregate Gradation on Pore Characteristics of Porous Asphalt Concrete." Materials 13, no. 6 (March 17, 2020): 1355. http://dx.doi.org/10.3390/ma13061355.

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Porous asphalt concrete (PAC) has been used to improve the traffic conditions in rainy weather due to its high porosity. Aggregate size and gradation have great impact on the connected pore structure, which ultimately affects the permeability of porous asphalt concrete. In this paper, the topological properties of connective pores including pore area, pore circularity, equivalent pore diameter, and void network of porous asphalt concrete with different nominal maximum aggregate sizes and gradations were analyzed using x-ray computer tomography scans and the image processing technique. It was observed that the maximum aggregate sizes will not have significant effect on the percentage of connected pores to total pores for porous asphalt concrete. Furthermore, the percentage of connected pores to total pores is related to the air void content, but for PAC-13 with 20% target air void content or above, the connectivity does not seem to have a sharp increase. Additionally, porous asphalt concrete with a smaller nominal particle size or lower target air void content seems to generate a more concentrated distribution of Eqdiameter. Moreover, pore circularities for porous asphalt concrete with a maximum aggregate size of 10 mm or above are independent of maximum aggregate sizes. Air void contents ranging from 16% to 21% do not have a significant effect on the voids’ circularity. Furthermore, the branching nodes in porous asphalt concrete with a smaller nominal maximum aggregate size or lower target air void content have a more uniform spatial distribution. However, the percentage of cross-linked number to total node raises as the nominal maximum aggregate size or target air void content increases.

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Prowell, Brian D., L. Allen Cooley, and Richard J. Schreck. "Virginia’s Experience with 9.5-mm Nominal-Maximum-Aggregate-Size Stone Matrix Asphalt." Transportation Research Record: Journal of the Transportation Research Board 1813, no. 1 (January 2002): 133–41. http://dx.doi.org/10.3141/1813-16.

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Nekkanti, Haripriya, Bradley J. Putman, and Behrooz Danish. "Influence of Aggregate Gradation and Nominal Maximum Aggregate Size on the Performance Properties of OGFC Mixtures." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 1 (January 2019): 240–45. http://dx.doi.org/10.1177/0361198118821628.

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The effect of aggregate gradation and nominal maximum aggregate size (NMAS) on the performance properties of open-graded friction courses (OGFC) mixtures was investigated in this research. Several tests which included porosity, surface texture, indirect tensile strength (ITS), shear strength, and Cantabro abrasion loss were used to compare eight different aggregate gradations having two NMAS (9.5 mm and 12.5 mm) all from one aggregate source. For each NMAS, the gradations varied by adjusting the percent passing the No. 4 (4.75 mm) sieve. The results indicated that aggregate gradation does influence the behavior of OGFC mixtures. An increase in percent passing the No. 4 sieve showed significant decreases in porosity, which were more pronounced for the 12.5 mm NMAS compared with the 9.5 mm NMAS. Conversely, the increase in the percent passing the No. 4 sieve generally resulted in increases in the mixture performance properties as measured by the ITS, Cantabro loss, and shear strength. The results of this study provide laboratory-based evidence that adjusting the OGFC gradation by increasing the allowable percent passing the No. 4 sieve toward the higher end of the current specification range (e.g., near 30% for 12.5 mm NMAS) could potentially have positive effects on mixture durability while also maintaining adequate permeability for water drainage.

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Ma, Li Jie, and Jin Yu Zhang. "Uniform Experimental Design of Coarse Aggregate Asphalt Pavement." Advanced Materials Research 753-755 (August 2013): 678–81. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.678.

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Coarse aggregate of asphalt mixture is crucial to the road performance. In this paper, by using the method of uniform design research, particle size of the aggregate were studied influence to CBR value with nominal maximum particle size 13.2mm aggregate. Further to determine the critical particle size grade by gray relational degree theory.

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Liu, Hongying, Peiwen Hao, and Jinzhi Xu. "Effects of Nominal Maximum Aggregate Size on the Performance of Stone Matrix Asphalt." Applied Sciences 7, no. 2 (January 26, 2017): 126. http://dx.doi.org/10.3390/app7020126.

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Li, Xinjun, Nelson Gibson, Xicheng Qi, Trenton Clark, and Kevin McGhee. "Laboratory and Full-Scale Evaluation of 4.75-mm Nominal Maximum Aggregate Size Superpave Overlay." Transportation Research Record: Journal of the Transportation Research Board 2293, no. 1 (January 2012): 29–38. http://dx.doi.org/10.3141/2293-04.

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A 4.75-mm nominal maximum aggregate size Superpave® mix developed by the Virginia Department of Transportation was placed as a thin treatment over existing, aged sections in an accelerated pavement test facility. Half the loaded wheelpath was paved with and half without the treatment to explore rutting susceptibility and quantify the ability to defer cracking. Loose mix was collected during construction to verify the mix design and for laboratory dynamic modulus, flow number, Hamburg wheel tracking, and axial fatigue testing. The mix was produced according to the volumetric specifications, but the in-place density was higher than the target. Although laboratory tests indicated poor resistance to rutting, full-scale performance illustrated that the total rutting in the treated sections was equal to or less than the total rutting in the sections without the overlay. Top-down cracking was significantly delayed as a result of the presence of the thin overlay, but once the pavement sections were aged and brittle, the treatment could not delay cracking.

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Howell, Ryan, Stephen Muench, James Feracor, Milad Ashtiani, and Jim Weston. "Field Performance of 9.5-mm Nominal Maximum Aggregate Size Asphalt Pavement in Washington State." Journal of Transportation Engineering, Part B: Pavements 146, no. 2 (June 2020): 04020024. http://dx.doi.org/10.1061/jpeodx.0000179.

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Khasawneh, Mohammad Ali, and Mohammad Ahmad Alsheyab. "Effect of nominal maximum aggregate size and aggregate gradation on the surface frictional properties of hot mix asphalt mixtures." Construction and Building Materials 244 (May 2020): 118355. http://dx.doi.org/10.1016/j.conbuildmat.2020.118355.

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11

Gong, X., Y. C. Ai, W. D. Liu, and G. H. Ge. "Analysis of the effect of gradation and maximum nominal particle size on coarse aggregate movement." IOP Conference Series: Earth and Environmental Science 510 (July 14, 2020): 052015. http://dx.doi.org/10.1088/1755-1315/510/5/052015.

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Mohd Hasan, Mohd Rosli, Jia Yih Eng, Meor Othman Hamzah, and J. L. M. Voskuilen. "The effects of break point location and nominal maximum aggregate size on porous asphalt properties." Construction and Building Materials 44 (July 2013): 360–67. http://dx.doi.org/10.1016/j.conbuildmat.2013.02.053.

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13

Ning, Chen, and Ming Hui Wang. "A Measurement Approach for Critical Voids in Mineral Aggregate Based on AC-20." Advanced Materials Research 108-111 (May 2010): 708–12. http://dx.doi.org/10.4028/www.scientific.net/amr.108-111.708.

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The voids in the mineral aggregate (VMA) is considered to be the most important mix design parameter which affects the durability of the asphalt concrete mix. This has traditionally been addressed during mix design by meeting a minimum voids in the mineral aggregate (VMA) requirement, based solely upon the nominal maximum aggregate size without regard to other significant aggregate-related properties. The goal of this study is to determine the validity of the minimum VMA requirement versus nominal maximum aggregate size required in Marshall volumetric mix design. Specimens were compacted using the Superpave Gyratory Compactor (SGC), conventionally tested for bulk and maximum theoretical specific gravities and physically tested using the thiaxial creep test system under a repeated load confined configuration to identify the transition state from sound to unsound. AC-20 was classified in the light of fine, dense and coarse gradation. The AC-20C, AC-20D and AC-20F asphalt mixtures were tested as the object of study. The results clearly demonstrate that the volumetric conditions of an VMA mixture at the stable unstable threshold are influenced by a composite measure of the aggregate size gradation .The currently defined VMA criterion, while significant, is seen to be insufficient by itself to correctly differentiate sound from unsound mixtures. Under current specifications, many otherwise sound mixtures are subject to rejection solely on the basis of failing to meet the VMA requirement. Based on the laboratory data and analysis, a new paradigm to volumetric mix design is proposed that explicitly accounts for aggregate gradation factors.

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14

Romero, Pedro, and Walaa S. Mogawer. "Evaluation of Ability of Superpave Shear Tester To Differentiate Between Mixtures with Different Aggregate Sizes." Transportation Research Record: Journal of the Transportation Research Board 1630, no. 1 (January 1998): 69–76. http://dx.doi.org/10.3141/1630-09.

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A study was conducted to determine whether the results from the Superpave shear tester (SST) could measure the effect of nominal maximum aggregate size on rutting susceptibility of asphalt mixtures without the need of a model. Four mixtures were analyzed using direct measurements from the SST. Two of the mixtures were prepared with AC-5 asphalt cement and nominal maximum aggregate sizes of 19.0 mm and 37.5 mm. The other two were prepared with AC-20 asphalt cement and the same two gradations. The results were analyzed statistically and compared with the performance of the respective mixtures tested by the FHWA Accelerated Loading Facility (ALF). The specimens were compacted to a target air voids of 7 percent using the Superpave gyratory compactor. The testing sequence consisted of performing the simple shear at constant height (SSCH) test followed by the frequency sweep at constant height (FSCH) test at 40°C and 58°C. These temperatures were chosen because they represent, respectively, the highest temperature used in Superpave complete analysis and the target pavement temperature at 20 mm depth used in the ALF tests. After the SSCH and FSCH tests, the repeated shear at constant height (RSCH) test was performed on all samples at 40°C. The ALF provided a significant decrease in rutting susceptibility with increase in aggregate size; however, the SST was unable to separate mixtures with the same binders and the two different nominal maximum aggregate sizes.

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Freire, Reuber A., Lucas F. A. L. Babadopulos, Verônica T. F. Castelo Branco, and Amit Bhasin. "Aggregate Maximum Nominal Sizes’ Influence on Fatigue Damage Performance Using Different Scales." Journal of Materials in Civil Engineering 29, no. 8 (August 2017): 04017067. http://dx.doi.org/10.1061/(asce)mt.1943-5533.0001912.

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16

Wang, Yi, and Wei Li. "Study on High Temperature Performance of Asphalt Mixture Based on Rutting Test." Applied Mechanics and Materials 744-746 (March 2015): 1316–19. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.1316.

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In order to deeply reveal the high temperature stability of asphalt mixture, rutting test was implemented to evaluate the high temperature stability of asphalt mixture, and the evaluation index is dynamic stability. The effect of asphalt type, degree of compaction, gradation type and nominal maximum aggregate size on rutting test results was studied respectively. The results showed that: modified asphalt can improve the high temperature stability of asphalt mixture effectively; the anti-rutting performance of asphalt mixture reduces gradually with decrease of the degree of compaction; the anti-rutting performance of SAC-16 is greater than that of AC-16; and the anti-rutting performance of asphalt mixture is improved with increase of the nominal size of aggregate.

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Diefenderfer, Stacey D., Benjamin F. Bowers, and Kevin K. McGhee. "Impact of Gyration Reduction and Design Specification Changes on Volumetric Properties of Virginia Dense-Graded Asphalt Mixtures." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 28 (July 13, 2018): 143–53. http://dx.doi.org/10.1177/0361198118787940.

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In 2015, the Virginia Department of Transportation (VDOT) proposed changes to their specification for asphalt mix design. The changes incorporated a reduction of design gyrations from 65 to 50; the addition of constraints on the No. 4 (4.75 mm) and No. 30 (600 µm) sieves; and adjustments to the production value for voids filled with asphalt and minimum voids in mineral aggregate. Before these modifications were fully adopted, a study was performed to assess the effect of the changes on mixture properties and laboratory performance. Eleven pairs of asphalt mixtures were evaluated; the pairs consisted of a typical VDOT 65-gyration mixture produced under the specification current at the time and a companion 50-gyration mixture designed and produced in accordance with the proposed specification. Mixtures were evaluated to determine the effect of the design parameters on volumetric properties, gradation, and permeability. The changes had very little effect on volumetric properties or gradation. Permeability effects were mixed, with 9.5 mm nominal maximum aggregate size mixtures requiring greater compaction to meet permeability requirements and 12.5 mm nominal maximum aggregate size mixtures showing improved permeability even at higher air-void contents. For the 50-gyration mixtures, core air voids were reduced, indicating the potential for increased durability attributable to improved densification in the field.

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Lou, Keke, Peng Xiao, Aihong Kang, Zhengguang Wu, and Pengcheng Lu. "Suitability of Fiber Lengths for Hot Mix Asphalt with Different Nominal Maximum Aggregate Size: A Pilot Experimental Investigation." Materials 13, no. 17 (August 20, 2020): 3685. http://dx.doi.org/10.3390/ma13173685.

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Fiber length is a key parameter for the mixture design of basalt fiber-reinforced hot mix asphalt (HMA), which significantly affects the mix performance. To evaluate the suitability of fiber lengths for HMA with different nominal maximum aggregate size (NMAS), basalt fiber with the lengths of 3, 6, 9, 12, and 15 mm were selected for dense graded gradations with different NMASs (namely, SUP-13, SUP-20, and SUP-25), so as to prepare the fiber-reinforced HMA mixtures. Then, the mix performance was evaluated by an indirect tensile asphalt cracking test (IDEAL-CT), a four-point bending beam fatigue test, a wheel tracking test, a uniaxial penetration test, a low temperature bending beam test, and a freeze-thaw splitting test. Based on the performance results, the optimum fiber length for each mix gradation was proposed by the normalization method. The results showed that adding basalt fiber can enhance the comprehensive performance of all three types of HMA to a great extent. Furthermore, fiber length presented remarkable impact on the crack resistance, the fatigue resistance of the HMA, and the low temperature crack resistance, but it had limited influence on the high temperature deformation resistance, and water stability. The optimum fiber length for SUP-13, SUP-20, and SUP-25 was 6, 9, and 12 mm, respectively.

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Chun, Sanghyun, Kukjoo Kim, and Bongsuk Park. "Evaluation of 4.75-mm Nominal Maximum Aggregate Size (NMAS) Mixture Performance Characteristics to Effectively Implement Asphalt Pavement System." International Journal of Highway Engineering 18, no. 1 (February 15, 2016): 33–41. http://dx.doi.org/10.7855/ijhe.2016.18.1.033.

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Hurley, Graham C., and Brian D. Prowell. "Evaluation of Infrared Ignition Furnace for Determination of Asphalt Content." Transportation Research Record: Journal of the Transportation Research Board 1861, no. 1 (January 2003): 44–50. http://dx.doi.org/10.3141/1861-06.

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The Troxler Model 4730 infrared ignition furnace was compared with a standard Thermolyne ignition furnace. Comparisons conducted with a single unit of each furnace type were based on the correction factor for aggregate loss during ignition, accuracy, and the variability of the measured asphalt content and aggregate degradation during ignition. Forty-eight samples representing two nominal maximum aggregate sizes (9.5 and 19.0 mm), four aggregate types (granite, crushed gravel, limestone, and dolomite), and two asphalt contents (optimum and optimum plus 0.5% asphalt content) were tested in each furnace. The results indicated that the correction factors for aggregate loss during ignition were significantly different for each type of furnace, thus requiring a separate calibration for each type of furnace. In practical terms, the differences for all but the 9.5-mm nominal maximum aggregate size (NMAS) limestone and both dolomite mixtures were less than 0.1%. The samples with the optimum plus 0.5% asphalt content were tested by using the calibration factors developed for a particular mix–furnace combination. The results were analyzed in terms of accuracy (bias) and variability (standard deviation). Neither the measured biases nor the standard deviations for the two types of furnaces were significantly different. The results obtained with four sieve sizes (NMAS and 4.75, 2.36, and 0.075 mm) were evaluated for aggregate breakdown. A comparison of the aggregate gradations recovered from both furnaces indicated no significant difference in the degree of aggregate degradation. A round-robin investigation should be conducted to confirm that the precision of the infrared furnace is similar to the precision of the standard furnace.

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Luo, Sang, Zhen-dong Qian, and Yong-chao Xue. "Performance evaluation of open-graded epoxy asphalt concrete with two nominal maximum aggregate sizes." Journal of Central South University 22, no. 11 (November 2015): 4483–89. http://dx.doi.org/10.1007/s11771-015-2996-6.

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Lou, Keke, Xing Wu, Peng Xiao, Aihong Kang, Zhengguang Wu, and Yan Xia. "Comprehensive Study about Effect of Basalt Fiber, Gradation, Nominal Maximum Aggregate Size and Asphalt on the Anti-Cracking Ability of Asphalt Mixtures." Applied Sciences 11, no. 5 (March 4, 2021): 2289. http://dx.doi.org/10.3390/app11052289.

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There are many parameters that could affect the properties of asphalt mixtures, such as the fiber additive, gradation type, nominal maximum aggregate size (NMAS), and asphalt. To evaluate the influence of these factors on the crack resistance of asphalt mixture, 10 different types of asphalt mixtures were prepared. The indirect tensile asphalt cracking test (IDEAL-CT) and semi-circle bending test (SCB) were adopted to test the anti-cracking ability of the test samples. The parameters of these two test results were also used to conduct the correlation analysis to find the correlation between different parameters, and scanning electron microscope (SEM) test was also used to analyze the micro cracks of asphalt mixture. The results showed that basalt fiber could further enhance the anti-cracking ability of asphalt mixture. Stone matrix asphalt (SMA) showed better anti-cracking performance than Superpave (SUP) asphalt mixtures. The increase in the nominal maximum aggregate size could decrease the anti-cracking ability of asphalt mixtures. Styrene-Butadiene-Styrene (SBS) modified asphalt could better reinforce the anti-cracking ability than pure asphalt. The CTindex of IDEAL-CT test and Flexibility index (FI) value of SCB test results showed better correlation. This paper has certain significance in guiding the design of asphalt mixtures having good crack resistance.

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Guo, Zhaoyang, Junyan Yi, Sainan Xie, Jianpeng Chu, and Decheng Feng. "Study on the Influential Factors of Noise Characteristics in Dense-Graded Asphalt Mixtures and Field Asphalt Pavements." Shock and Vibration 2018 (August 28, 2018): 1–13. http://dx.doi.org/10.1155/2018/5742412.

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Determining the influential factors of noise characteristics in dense-graded asphalt mixtures and field asphalt pavement is important in constructing highways that are both low noise and environmentally friendly. In this study, the effects of nominal maximum aggregate size, asphalt binder type, air void percentage, and the service life of pavement on the noise absorption characteristics of asphalt mixtures were first investigated in laboratory. Thereafter, tire/pavement noise measurements were conducted on different types of dense-graded asphalt pavements. The effects of the service lives of the pavements, the types of the pavements, driving speeds, and test temperatures on the noise levels of the pavements were also studied. The Zwicker method is used to calculate psychoacoustic parameters on the tire/pavement noise spectrum. The laboratory results indicate that reducing the nominal maximum aggregate size, using rubber asphalt, and increasing air void percentage as well as surface texture depth improve the sound absorption performance of asphalt mixtures. The field measurements show that laying down asphalt pavements with a shorter service life or larger texture depth, using rubber asphalt, reducing traffic speed, and increasing air temperature can reduce noise.

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Hurley, Graham C., and Brian D. Prowell. "Refinement of the Hot-Mix Asphalt Ignition Method for High-Loss Aggregates." Transportation Research Record: Journal of the Transportation Research Board 1907, no. 1 (January 2005): 128–34. http://dx.doi.org/10.1177/0361198105190700115.

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Four methodologies for determining the asphalt content of mixtures containing high-loss aggregates in the ignition furnace were evaluated: the standard method using the Thermolyne furnace (control), the Troxler NTO infrared furnace, the Ontario method, and a Tempyrox glass-cleaning oven. Six aggregate sources with high ignition furnace aggregate corrections were obtained from around the country: four dolomites, a basalt, and a serpentine/chlorite. Calibration factors were determined for each method at optimum asphalt content. Additional samples were then tested at optimum plus 0.5% asphalt content, and the measured asphalt content was calculated by using the correction factor determined for that method and aggregate source. The Tempyrox Pyro-Clean furnace, commonly used for cleaning laboratory glassware, produced the lowest aggregate correction factors. The standard method and the Ontario method, both using the Thermolyne ignition furnace, produced the smallest bias or error in measured asphalt content. The standard deviation of the corrected asphalt contents for these high-loss sources was higher than the within-laboratory standard deviation reported for AASHTO T308. The only exception was the Alabama source using the standard method. The Ontario method and Tempyrox oven generally reduced the variability of asphalt content measurements for high-loss aggregates. None of the methods evaluated statistically reduced aggregate breakdown on the nominal maximum aggregate size and 4.75-mm sieves. The Ontario method significantly reduced, but did not eliminate, aggregate breakdown on the 0.075-mm sieve. The Ontario method is the best method for immediate implementation for determining the asphalt content by the ignition method for high-loss aggregates.

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Birgisson, Bjorn, and Reynaldo Roque. "Evaluation of the Gradation Effect on the Dynamic Modulus." Transportation Research Record: Journal of the Transportation Research Board 1929, no. 1 (January 2005): 193–99. http://dx.doi.org/10.1177/0361198105192900123.

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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.

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Akita, Hiroshi, Dariusz Alterman, and Hideo Koide. "Size Effect of Concrete in Uniaxial Tension." Advanced Materials Research 41-42 (April 2008): 227–32. http://dx.doi.org/10.4028/www.scientific.net/amr.41-42.227.

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In order to investigate the size effect of concrete, four sizes of rectangular prisms were tested in uniaxial tension. The cross sections of the prisms were 50x100mm, 100x100mm, 200x100mm and 400x100mm. The concrete was an ordinary one with the compressive strength of 34 MPa and the maximum aggregate size of 20mm. Notches were applied on four side faces and secondary flexure was completely eliminated during the test in order to obtain the exact nominal tensile strength. The size effect was analyzed by four factors, namely tensile strength, fracture energy, critical crack opening displacement and tension softening curves. Clear size dependence was observed in critical crack opening displacement and initial convexity of tension softening curves, and a slight size dependence was observed in tensile strength. On the other hand, size effect was unclear in fracture energy and other part of tension softening curves because of their scatters.

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Ismael, Mohammed Qadir, and Reem Fouad Ahmed Al-Harjan. "Evaluation of Job-Mix Formula Tolerances as Related to Asphalt Mixtures Properties." Journal of Engineering 24, no. 5 (May 1, 2018): 124. http://dx.doi.org/10.31026/j.eng.2018.05.09.

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The current Iraqi standard specifications for roads and bridges allowed the prepared Job-Mix Formula for asphalt mixtures to witness some tolerances with regard to the following: coarse aggregate gradation by ± 6.0 %, fine aggregate gradation by ± 4.0 %, filler gradation by ± 2.0 %, asphalt cement content by ± 0.3 % and mixing temperature by ± 15 oC. The objective of this work is to evaluate the behavior of asphalt mixtures prepared by different aggregates gradations (12.5 mm nominal maximum size) that fabricated by several asphalt contents (40-50 grade) and various mixing temperature. All the tolerances specified in the specifications are taken into account, furthermore, the zones beyond these tolerances are also observed. The evaluation process is illustrated by volumetric properties such as density, air voids, voids in mineral aggregate and voids filled with asphalt. Marshall test is carried out to find stability and flow values. The resistance to moisture effect is investigated by conducting the compressive test for dry and water immersed conditions to find the index of retained strength. The experimental results supported the recommendations to increase tolerances of coarse and fine aggregate gradations to ± 7.0 % and ± 5.0 % respectively. The optimum asphalt content tolerance can be increased to ± 0.5 %. The tolerances of filler gradation and mixing temperature are preferable to keep their current values.

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Ghimire, Anjana, and Sanjeev Maharjan. "Experimental Analysis on the Properties of Concrete Brick With Partial Replacement of Sand by Saw Dust and Partial Replacement of Coarse Aggregate by Expanded Polystyrene." Journal of Advanced College of Engineering and Management 5 (December 11, 2019): 27–36. http://dx.doi.org/10.3126/jacem.v5i0.26674.

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An experimental study had been conducted to study the effects of saw dust and EPS as partial replacement of sand and coarse aggregate in various percentages such as 0%, 10%, 20% and 30% in concrete brick samples of M20 and M15 Grade. Compressive strength, Bulk density and Water absorption of prepared saw dust and EPS M20 and M15 concrete brick were determined. The properties of materials were first determined before the conduction of experimental works. The normal consistency, initial and final setting time and compressive strength of cement used for the experiment were found as 31%,115 minutes, 265 minutes and 39.5 N/mm2 respectively. Sieve analysis to determine the particle size distribution of sand, coarse aggregates, saw dust and EPS was performed. From the sieve analysis, the nominal maximum size of sand, coarse aggregate, saw dust and EPS used for preparing concrete brick sample were 2.36 mm, 12.5 mm, 2.36 mm and 4.75 mm respectively. Impact value of coarse aggregate obtained was 11.20 %.The experimental results showed that water absorption of prepared M15 and M20 concrete brick samples increased with increase in percentage replacement of sand by saw dust and EPS by coarse aggregate. Compressive strength and Bulk density of prepared M15 and M20 concrete brick sample decreased with increase in percentage content of saw dust and EPS. The results showed that the partial replacement of sand by saw dust and coarse aggregate by EPS in concrete brick sample had sufficient strength as compared to common bricks.

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Norhidayah, Abdul Hassan, Mohd Zul Hanif Mahmud, and Putra Jaya Ramadhansyah. "Air Void Characterisation in Porous Asphalt Using X-Ray Computed Tomography." Advanced Materials Research 911 (March 2014): 443–48. http://dx.doi.org/10.4028/www.scientific.net/amr.911.443.

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This study presents the characterisation of the air voids distribution for porous asphalt mixtures compacted using gyratory compactor. The distribution of voids content and voids shape within the porous asphalt were characterised for different nominal maximum aggregate size (NMAS) and specimen height. This is to evaluate the effect of different aggregate size composition and lift thickness on the air voids characteristics of the compacted porous asphalt. Two types of gradations were adopted i.e. Grading A (with NMAS=10 mm) and Grading B (with NMAS=14 mm) and they were fabricated for two different heights (50 and 100 mm). The internal structure was captured using X-ray Computed Tomography and image analysis techniques were used to process and analyse the images. It was found that mixture with coarse aggregate gradation produced larger void size with an elongated shape, which indicates voids connectivity within the mixture compared to fine gradation with more circular and smaller void size.For lift thickness, itacts differentlyfor different aggregate gradations. The specimen produced greater voids connectivity when the fine and coarse gradations were compacted at 100 mm and 50 mm respectively. These show that NMAS and lift thickness influence the mobility of the aggregate particles during compaction which affect the voids formation and determine the effectiveness of the compaction.

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Pan, Tongyan, Erol Tutumluer, and Samuel H. Carpenter. "Effect of Coarse Aggregate Morphology on the Resilient Modulus of Hot-Mix Asphalt." Transportation Research Record: Journal of the Transportation Research Board 1929, no. 1 (January 2005): 1–9. http://dx.doi.org/10.1177/0361198105192900101.

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The resilient modulus measured in the indirect tensile mode according to ASTM D 4123 reflects effectively the elastic properties of asphalt mixtures under repeated load. The coarse aggregate morphology quantified by angularity and surface texture properties affects resilient modulus of asphalt mixes; however, the relationship is not yet well understood because of the lack of quantitative measurement of coarse aggregate morphology. This paper presents findings of a laboratory study aimed at investigating the effects of the material properties of the major component on the resilient modulus of asphalt mixes, with the coarse aggregate morphology considered as the principal factor. With modulus tests performed at a temperature of 25°C, using coarse aggregates with more irregular morphologies substantially improved the resilient modulus of asphalt mixtures. An imaging-based angularity index was found to be more closely related to the resilient modulus than an imaging-based surface texture index, as indicated by a higher value of the correlation coefficient. The stiffness of the asphalt binder also had a strong influence on modulus. When the resilient modulus data were grouped on the basis of binder stiffnesses, the agreement between the coarse aggregate morphology and the resilient modulus was significantly improved in each group. Although the changes in aggregate gradation did not significantly affect the relationship between the coarse aggregate morphology and the resilient modulus, decreasing the nominal maximum aggregate size from 19 mm to 9.5 mm indicated an increasing positive influence of aggregate morphology on the resilient modulus of asphalt mixes.

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Wu, Kuang Huai, Guo Liang Yang, and Ai Yu Zeng. "Design of Rubberized Asphalt Concrete by Means of Coarse Aggregate Void Filling Method." Advanced Materials Research 463-464 (February 2012): 215–20. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.215.

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In order to find a convenient approach to design the mix of rubberized asphalt concrete (RAC) and make full use of the properties of RAC, a kind of RAC-13 (13 is the nominal maximum aggregate size of the mixture) was designed by means of coarse aggregate void filling method (CAVF). A series of conventional tests of asphalt mixture with five asphalt-rubber aggregate ratio(ARAR) were carried out to check the target mix design and evaluate the performance of RAC. Performance evaluation tests such as Marshall and submerged Marshall stability test, moisture damage test and wheel tracking test were included. Test results show that the high temperature stability, moisture susceptibility and road performance of RAC-13 designed with CAVF method are all favorable. The recommended optimum asphalt-rubber aggregate ratio(OARAR) is 7.1% under the condition of skeleton structure. CAVF is a good means for designing RAC to ensure its stone-on-stone contact structure.

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Dang, Dang Tung, Manh Tuan Nguyen, Ngoc Tram Hoang, and Anh Thang Le. "Laboratory Assessment of Dense Graded Asphalt Concrete Incorporating Coal Furnace Ash in South of Vietnam." Key Engineering Materials 879 (March 2021): 117–25. http://dx.doi.org/10.4028/www.scientific.net/kem.879.117.

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Currently, application of industrial waste or by-product in road construction industrials is a major interest by researchers, government officers and engineers. Coal ashes by-product from industrial parks negatively impact environment, costly in treatment, and require large ground for disposing areas. Therefore, this paper proposes on using the coal ash from furnace products of an industrial park in South of Vietnam to be incorporated into dense graded asphalt concrete using Nominal Maximum Aggregate Size 12.5mm. Laboratory performance tests including Marshall stability, indirect tensile strength, Cantabro loss, and dynamic fatigue test were conducted. The effects of coal ash contents in replacement of fine aggregate which is passing 4.75mm sieve from asphalt mixture into laboratory performance of mixture is also discussed in detail.

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Khasawneh, Mohammad Ali, and Mohammad Ahmad Alsheyab. "Corrigendum to “Effect of nominal maximum aggregate size and aggregate gradation on the surface frictional properties of hot mix asphalt mixtures” [Constr. Build. Mater. 244 (2020) 118355]." Construction and Building Materials 273 (March 2021): 121983. http://dx.doi.org/10.1016/j.conbuildmat.2020.121983.

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Fu, Hao, Chaohui Wang, GongXin Yu, Qian Chen, and Luqing Liu. "Design Optimization and Performance Evaluation of the Open-Graded Friction Course with Small Particle Size Aggregate." Advances in Civil Engineering 2021 (February 11, 2021): 1–11. http://dx.doi.org/10.1155/2021/6668378.

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This study aims to optimize the bonding performance between the wearing course and the used pavement or the underlying layer and further improve the service quality and durability of the open-graded friction course with small particle size aggregate (ultrathin OGFC). The ultrathin OGFC including waterborne epoxy resin emulsified asphalt (WEA) bonding layer and open-graded asphalt concrete with 9.5 mm nominal maximum aggregate size gradation was optimized. The construction timing of the open-graded asphalt mixture was determined. The road performance, wear resistance, and interlaminar bonding durability of the ultrathin OGFC were comprehensively evaluated. The results show that, based on the basic properties of the open-graded asphalt mixture, its asphalt aggregate ratio is recommended to be 5.0–5.5%. Based on interlaminar shear strength, it is recommended that the open-graded asphalt mixture is paved immediately after WEA bonding material was sprayed, and the bonding layer does not spread aggregate. The WEA containing 20% waterborne epoxy resin (WER) is recommended as bonding layer for the ultrathin OGFC, and the optimized spraying amount is 1 kg/m2. The ultrathin OGFC has good antisliding, drainage, and wear resistance properties. The interlaminar bonding performance, water stability, and durability of WEA bonding layer are obviously better than those of high viscosity asphalt (HVA) and SBS-modified asphalt. The WEA bonding layer can better resist interlaminar shear failure and improve the service quality and service life of the ultrathin OGFC.

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Mrawira, Donath M., and Joseph Luca. "Effect of aggregate type, gradation, and compaction level on thermal properties of hot-mix asphalts." Canadian Journal of Civil Engineering 33, no. 11 (November 1, 2006): 1410–17. http://dx.doi.org/10.1139/l06-076.

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This paper investigates the effects of mix design factors on the thermal properties of Superpave asphalt concrete. The thermal properties were measured using a guarded testing device (k-alpha device) developed recently at the University of New Brunswick. Two aggregate types, three gradations (determined by the material retained on a 4.75 mm sieve), and four compaction levels (at 35, 70, 100, and 160 gyrations) were investigated. The aggregate was 12.5 mm maximum nominal size with PG58-34 asphalt binder used for all mixes. The findings show that the thermal conductivity of the asphalt concrete ranged from 1.7 to 2.1 W/m·K. The specific heat capacity varied with the aggregate source and ranged from 940 to 2000 J/kg·K. The thermal diffusivity was found to vary with aggregate source. The aggregate type was found to have the most significant effect on the thermal properties. The compaction level had an effect but not a statistically significant one. The range of thermal properties determined in this paper is comparable to that found in the literature.Key words: thermal properties, asphalt concrete, pavement temperature prediction, heat conduction, transient state, thermal conductivity, thermal diffusivity, heat capacity.

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Salari, Saman, Samuel Cooper, Louay N. Mohammad, and Peyman Barghabany. "Development of a 4.75 mm asphalt mixture design for Implementation in Louisiana DOTD Specifications." International Journal of Pavement Research and Technology 13, no. 6 (November 2020): 637–44. http://dx.doi.org/10.1007/s42947-020-6014-5.

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AbstractThe Louisiana Department of Transportation and Development (DOTD) and other state agencies are continuously looking for techniques to reduce roadway maintenance and construction costs. A common consideration is to introduce asphalt mixtures with a smaller nominal maximum aggregate size (NMAS) for utilization in roadways. In a previous study, DOTD concluded that mixtures with a 4.75 mm NMAS provided acceptable performance as a surface layer. Excessive stockpiles of unused smaller aggregates can result in an economically competitive source to be consi dered for asphalt mixtures. The DOTD developed mixtures with four aggregate types and two binder types. A comprehensive evaluation of performance was conducted through volumetric and mechanistic testing. Performance testing consisted of the Loaded Wheel Tracking (LWT) test to determine rutting resistance, Semi-Circular Bend (SCB) test to evaluate intermediate temperature cracking resistance, and dynamic modulus (E*) to ascertain the stiffness at intermediate temperatures. As expected, asphalt binder grade, aggregate type and mixture composition affected the performance of mixtures evaluated. Gravel mixtures were susceptible to cracking, while limestone mixtures were susceptible to rutting. An economic analysis was conducted to determine the viability of 4.75 mm mixtures. The cost per ton of 4.75 mm mixtures in Louisiana was higher than conventional 12.5 mm mixtures. However, when considering the lift thickness of potential overlays, the 4.75 mm aggregate mixtures became more viable. Further, a life-cycle analysis of a designed pavement using AASHTO Pavement-ME was performed to compare the lifetime durability of the 4.75 mm NMAS mixtures to a conventional 12.5 mm mixture.

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Lee, Seong-Hyeok, Dae-Wook Park, Hai Viet Vo, and Samer Dessouky. "Asphalt Mixture for the First Asphalt Concrete Directly Fastened Track in Korea." Advances in Materials Science and Engineering 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/701940.

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The research has been initiated to develop the asphalt mixtures which are suitable for the surface of asphalt concrete directly fastened track (ADFT) system and evaluate the performance of the asphalt mixture. Three aggregate gradations which are upper (finer), medium, and below (coarser). The nominal maximum aggregate size of asphalt mixture was 10 mm. Asphalt mixture design was conducted at 3 percent air voids using Marshall mix design method. To make impermeable asphalt mixture surface, the laboratory permeability test was conducted for asphalt mixtures of three different aggregate gradations using asphalt mixture permeability tester. Moisture susceptibility test was conducted based on AASHTO T 283. The stripping percentage of asphalt mixtures was measured using a digital camera and analyzed based on image analysis techniques. Based on the limited research results, the finer aggregate gradation is the most suitable for asphalt mixture for ADFT system with the high TSR value and the low stripping percentage and permeable coefficient. Flow number and beam fatigue tests for finer aggregate asphalt mixture were conducted to characterize the performance of asphalt mixtures containing two modified asphalt binders: STE-10 which is styrene-butadiene-styrene (SBS) polymer and ARMA which is Crum rubber modified asphalt. The performance tests indicate that the STE-10 shows the higher rutting life and fatigue life.

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Ismael, Mohammed Qadir, and Ahmed Hussein Ahmed. "Effect of Hydrated Lime on Moisture Susceptibility of Asphalt Mixtures." Journal of Engineering 25, no. 3 (February 28, 2019): 89–101. http://dx.doi.org/10.31026/j.eng.2019.03.08.

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Moisture induced damage can cause a progressive deterioration in the performance of asphalt pavement by the loss of adhesion between asphalt binder and aggregate surface and/or loss of cohesion within the binder in the presence of water. The objective of this paper is to improve the asphalt mixtures resistance to moisture by using hydrated lime as an anti-stripping additive. For this purpose, two types of asphalt binder were utilized; asphalt grades (40-50) and (60-70) with one type of aggregate of 19.0 mm aggregate nominal maximum size, and limestone dust as a mineral filler. Marshall method was adopted to find the optimum asphalt content. Essentially, two parameters were determined to evaluate the moisture susceptibility, namely: The Index of Retained Strength and the Tensile Strength Ratio. The hydrated lime was added by 1.0, 1.5, and 2.0 percentages (by weight of aggregate) using the saturated surface dry method. It was concluded that using hydrated lime will improve the moisture damage resistance. This was adopted as the value of tensile strength ratio increased by 24.50 % and 29.16% for AC (40-50) and AC (60-70) respectively, furthermore, the index of retained strength also increased by 14.28 % and 17.50 % for both asphalt grades. The optimum hydrated lime content founded to be 1.5 %.

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Ma, Xiang, Hao Wang, and Peisheng Zhou. "Novel Gradation Design of Porous Asphalt Concrete with Balanced Functional and Structural Performances." Applied Sciences 10, no. 20 (October 9, 2020): 7019. http://dx.doi.org/10.3390/app10207019.

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To improve the permeability of porous asphalt concrete (PAC) with a small nominal maximum aggregate size (NMAS) of 10 mm (PAC10), a novel gradation design by excluding the 0.075–3 mm aggregate was developed. This study aims to evaluate the functional and structural performances of the novel PAC10 with various mineral filler contents, using the conventional PAC10 and 13 mm NMAS PAC (PAC13) as reference, and develop the optimum gradation of the novel PAC10. The performance properties evaluated include moisture susceptibility, durability, high-temperature stability, low-temperature cracking resistance and permeability. The results indicated that for the two conventional PACs with the same fine aggregate and mineral filler content, PAC10 had worse permeability and rutting resistance, similar moisture susceptibility and durability, and better low-temperature cracking resistance, compared with the PAC13. The novel PAC10 showed better permeability than the conventional PAC10. With the increase of the mineral filler content, the structural performance of the novel PAC10 is improved, but its permeability is decreased. With a mineral filler content of 6%, the novel PAC10 can have balanced functional and structural performances, which are equivalent to those of the conventional PAC13.

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Cocconcelli, Cristian, Bongsuk Park, Jian Zou, George Lopp, and Reynaldo Roque. "Fracture-Tolerant and Shear-Resistant Interlayers for Mitigation of Reflective Cracking." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 10 (May 12, 2019): 35–46. http://dx.doi.org/10.1177/0361198119847622.

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Reflective cracking is frequently reported as the most common distress affecting resurfaced pavements. An asphalt rubber membrane interlayer (ARMI) approach has been traditionally used in Florida to mitigate reflective cracking. However, recent field evidence has raised doubts about the effectiveness of the ARMI when placed near the surface, indicating questionable benefits to reflective cracking and increased instability rutting potential. The main purpose of this research was to develop guidelines for an effective alternative to the ARMI for mitigation of near-surface reflective cracking in overlays on asphalt pavement. Fourteen interlayer mixtures, covering three aggregate types widely used in Florida, and two nominal maximum aggregate sizes (NMAS) were designed according to key characteristics identified for mitigation of reflective cracking, that is, sufficient gradation coarseness and high asphalt content. The dominant aggregate size range—interstitial component (DASR-IC) model was used for the design of all mixture gradations. A composite specimen interface cracking (CSIC) test was employed to evaluate reflective cracking performance of interlayer systems. In addition, asphalt pavement analyzer (APA) tests were performed to determine whether the interlayer mixtures had sufficient rutting resistance. The results indicated that interlayer mixtures designed with lower compaction effort, reduced design air voids, and coarser gradation led to more cost-effective fracture-tolerant and shear-resistant (FTSR) interlayers. Therefore, preliminary design guidelines including minimum effective film thickness and maximum DASR porosity requirements were proposed for 9.5-mm NMAS (35 µm and 50%) and 4.75-mm NMAS FTSR mixtures (20 µm and 60%) to mitigate near-surface reflective cracking.

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Zhu, Feng, and De Dong Guo. "Influence of Graduation on Road Performance of Fibers-Reinforced Asphalt Pavement." Advanced Materials Research 753-755 (August 2013): 754–57. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.754.

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Rutting test, residual stability test and freeze-thaw split test were used to measure the properties of asphalt mixture with different graduation and same mixing amount of fibers, the results were analyzed to obtain the influence of graduation types in the road performance of fiber-reinforced asphalt mixture. The results showed as follows: fibers could obvious improve the high temperature property and water stability of asphalt mixture; the graduation types have visible impact on the improvement of all properties of fibers-reinforced asphalt mixture; SMA-13 has the greatest influence in improving the performance of fibers-reinforced mixture; the improving effect of dense graduation AC mixture will gradually decrease when the nominal maximum aggregate size was becoming bigger; graduation optimization design should be used in mix design of fibers-reinforced mixture to enhance its road performance.

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42

Chen, Jian-Shiuh, Yang-Chou Sun, Min-Chih Liao, and Chien-Chung Huang. "Effect of Binder Types on Engineering Properties and Performance of Porous Asphalt Concrete." Transportation Research Record: Journal of the Transportation Research Board 2293, no. 1 (January 2012): 55–62. http://dx.doi.org/10.3141/2293-07.

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Porous asphalt concrete (PAC) has an open-graded aggregate mixture to yield high air voids; PAC is mainly applied to the surface drainage layer on high-speed trafficked highway pavements. The objective of the study was to investigate the effect of binder types on the engineering properties and field performance of PAC mixtures. Three binder types were selected for a 19-mm nominal maximum aggregate size gradation: conventional asphalt AR-80, polymer-modified asphalt, and high-viscosity asphalt. A series of laboratory tests were conducted to evaluate the engineering properties of the PAC mixture, including permeability, resistance to draindown, resistance to disintegration, resistance to rutting, and resistance to indirect traction. A 3-km in-service test road was constructed to monitor the performance of PAC pavements using these three binders. Polymer-modified binder was shown to minimize abrasion loss and enhance the durability of the PAC mixture. Test results indicated that the use of polymer-modified binder, instead of unmodified binder, reduced rutting and raveling. When the mixture contained high-viscosity binder, it showed the best performance in the field. Field measurements indicated improved drainage as a result of replacement of the conventional asphalt AR-80 binder with the polymer-modified and high-viscosity binders. PAC pavement surfaces provided good frictional characteristics once the asphalt binder film was worn from the aggregate.

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43

Chun, Sanghyun, Kukjoo Kim, James Greene, and Bouzid Choubane. "Evaluation of top-down cracking potential for asphalt pavements with 4.75 mm nominal maximum aggregate size mixture layer using full-scale field tests and finite element analysis." Road Materials and Pavement Design 19, no. 5 (March 13, 2017): 1089–101. http://dx.doi.org/10.1080/14680629.2017.1300596.

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44

Idham, Mohd Khairul, Hainin Mohd Rosli, Haryati Yaacob, M. Naqiuddin M. Warid, and Mohd Ezree Abdullah. "Effect of Aging on Resilient Modulus of Hot Mix Asphalt Mixtures." Advanced Materials Research 723 (August 2013): 291–97. http://dx.doi.org/10.4028/www.scientific.net/amr.723.291.

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Asphalt hardens as a result of an aging process. This study was undertaken to determine the effect of field aging simulated by laboratory aging method of different hot mix asphalt (HMA) mixture. Three types HMA mixtures were used for this study namely Asphaltic Concrete with 10 mm nominal maximum aggregate size (AC 10), Aspaltic Concrete 28 mm (AC 28) and Porous Asphalt 10 mm (PA 10). The resilient modulus test was carried out as an indicator of the performance at a 25 °C and 40 °C. Generally, all samples show similar trend which aged mixture produced slightly higher resilient modulus compared to unaged mixture while an increase in temperature from 25 °C to 40 °C might reduced the resilient modulus up to 88%. This study also found that the difference increment of resilient modulus after the aging process attributed by asphalt content, air void and gradation of respective mixtures.

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KHABIRI, Mohammad Mehdi, Pooya AFKHAMY MEYBODI, and Ali Mohammad MONTAZERI. "EVALUATION OF THE EFFECT OF VARIOUS SURFICIAL POLLUTANTS AND ENVIRONMENTAL CONDITION ON SURFACE FRICTION PERFORMANCE OF ROAD PAVEMENT." Scientific Journal of Silesian University of Technology. Series Transport 112 (September 1, 2021): 99–111. http://dx.doi.org/10.20858/sjsutst.2021.112.7.8.

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Skip resistance of asphalt is an important parameter that can influence the safety of drivers on roads. Although there is a linear relationship between slipping on road surfaces and accidents, the impacts of pollutants for decreasing friction of roads is clear to researchers. Moisture and temperature influence friction and safety. In this research in SMA samples, three different gradations with the maximum nominal sizes of 19, 12.5 and 9.5, based on international standards were used. For polluting the surface, five materials that are found on roads were used, including fine-grained soil, sand, oil, soot and rubber powder. To measure the skip resistance, the British pendulum tester was used and for analysing macro-texture, the sand patch method was used. The results of this research showed that by increasing the maximum nominal size of aggregates, the depth of macro-texture in surfaces are grown and this is due to the decrease of fine aggregates in larger gradations. Because of the higher flexibility of pure bitumen, the applied compression pressure on rigid aggregates can cause indentations in the substrate and result in declining the roughness height of aggregates in the mixed surface. This leads to declining the hysteresis part of friction by increasing temperature.

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Liu, Guoqiang, Dongdong Han, and Yongli Zhao. "Quantitative Investigation of Aggregate Skeleton Force Chains of Asphalt Mixtures Based on Computational Granular Mechanics." Advances in Civil Engineering 2020 (May 11, 2020): 1–14. http://dx.doi.org/10.1155/2020/2196503.

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For asphalt mixtures, the difference between strong force chains (SCF) can reflect the skeleton performance. In this paper, six kinds of mineral mixture discrete element model were established. And various SCF evaluation indices of different mineral mixtures were calculated. Results indicate that the short length SCF number proportions of dense-skeleton type mineral mixtures are higher than that of dense-suspended type mineral mixtures under the same nominal maximum aggregate size (NMAS). And the NMAS has a great influence on the SCF length cumulative proportions, and different NMAS can significantly change the stress transfer path for dense-suspended type mixture. Nevertheless, the SCF length cumulative proportions have consistency for dense-skeleton type mixtures. The small SCF alignment coefficient proportions of dense-suspended type mixtures are higher than that of dense-skeleton type mixtures. In particular, under larger NMAS, the difference is more obvious. The SCF that is close to straight line is conducive to transfer loading. Therefore, dense-skeleton type mixture has better rutting resistance. The SCF bears the main loading for mixtures. Mixtures stone matrix asphalt (SMA) has a stronger bearing capacity than that of mixtures AC under the same NMAS. These findings provide insight into the mechanics of skeleton structure.

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Khan, Md Zahid Hossain, Suhana Koting, Herda Yati Binti Katman, Mohd Rasdan Ibrahim, Ali Mohammed Babalghaith, and Obada Asqool. "Performance of High Content Reclaimed Asphalt Pavement (RAP) in Asphaltic Mix with Crumb Rubber Modifier and Waste Engine Oil as Rejuvenator." Applied Sciences 11, no. 11 (June 4, 2021): 5226. http://dx.doi.org/10.3390/app11115226.

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The utilisation of reclaimed asphalt pavement (RAP) as a suitable substitute for natural aggregate and binder offers an energy-saving and cost-effective approach to enhance the performance of asphalt mix. Realising the potential use of RAP as a promising recycling technique, many countries are seeking to recycle RAP as part of the global effort to address the rising challenge of climate change and contribute to a sustainable environment. This study aimed to develop an integrated approach to determine the amount of RAP to be used in an asphaltic concrete wearing course with 14 mm nominal maximum aggregate size (ACW14). The RAP was incorporated with two waste materials comprising waste engine oil (WEO) as a rejuvenator and Crumb Rubber (CRM) as a binder modifier. A total of five different mixes, which include R0 (control mix), R30, R50, R70, and R100 (replacement of 30%, 50%, 70%, and 100% of RAP aggregates in the mix, respectively) were evaluated. The Marshall parameters, resilient modulus (MR), indirect tensile fatigue, moisture susceptibility, and mass loss (ML) tests were conducted to investigate the performance of each mix. Finally, an arbitrary scale was developed to optimise the RAP content. The results showed that the Marshall parameters, moisture susceptibility, and ML values of the RAP mixes met the criteria outlined in the standard. According to the MR performance, the R50, R70, and R100 mixes were more resilient than the R0. In terms of fatigue resistance, the R30, R50, and R70 mixes showed better performance than the R0. Overall, the collective performance of all RAP mixes was above the R0 and it increased with the increment of RAP content. Therefore, it was possible to design ACW14 mixes with up to 100% RAP in combination with WEO and CRM.

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Bowers, Benjamin F. "Laboratory Evaluation of Mixture Type on Highly Modified Asphalt Mixtures in Virginia." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 28 (September 9, 2018): 59–68. http://dx.doi.org/10.1177/0361198118792998.

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The work presented attempts to address reflective cracking of asphalt-surfaced pavements through binder modification with a highly polymer (HP)-modified asphalt binder. Nine asphalt mixtures ranging from fine dense-graded mixtures to stone matrix asphalt (SMA) mixtures were investigated with conventional polymer modified binders and HP binder. The dynamic modulus test, overlay test (OT), and semi-circular bend (SCB) test were used to evaluate the mixtures. In the cracking tests, HP mixtures outperformed the conventionally modified control mixtures for the same mixture type. For HP mixtures, in general, SMA mixtures performed better in the cracking test than dense-graded mixtures. One of the dense-graded mixtures having larger nominal maximum aggregate size (NMAS) performed better than the mixture with a smaller NMAS, whereas the other having a larger NMAS was not significantly different in crack testing. Further, a discussion on the calculation of bulk specific gravity and percent air voids in a cut OT and SCB specimen using saturated surface dry or vacuum sealing methods is presented.

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Long, Wu-Jian, Kamal Henri Khayat, and Feng Xing. "Correlations Among Various Self-Consolidating Concrete Workability Responses." Open Civil Engineering Journal 6, no. 1 (March 22, 2012): 38–47. http://dx.doi.org/10.2174/1874149501206010038.

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Self-consolidating concrete (SCC) mixtures designated for precast, prestressed applications should be highly workable to flow easily through restricted spacing and completely encapsulate reinforcements without any mechanical vibration. Key workability characteristics of SCC can be described in terms of filling ability, passing ability, and resistance to segregation. These properties are typically characterized by data that relate to specific testing methods. In general, these methods include the components required for evaluating simultaneously filling ability, passing ability, and resistance to segregation, since these properties are rather interrelated. In this investigation, 33 SCC mixtures made with various mixture proportioning parameters, including maximum size and type of aggregate, type and content of binder, and w/cm were evaluated. The mixtures were prepared using crushed aggregate and gravel of three different nominal sizes, w/cm of 0.33 and 0.38, and three binder compositions: Type MS cement, Type HE cement with 30% of slag replacement, and Type HE cement with 20% of Class F fly ash. Comparisons and correlations among various test results used in evaluating the workability responses obtained for these mixtures are established. This is done to highlight advantages and limitations of the various test methods that can be used to assess workability of SCC designated for prestressed applications. Appropriate combinations of test methods that can be used to assess workability of SCC at the precast plant are recommended, and ranges of acceptance of the various test methods are established.

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Al-Khateeb, Ghazi, Xicheng Qi, Aroon Shenoy, Kevin Stuart, and Terry Mitchell. "Assessment of Aging at FHWA's Pavement Testing Facility." Transportation Research Record: Journal of the Transportation Research Board 1940, no. 1 (January 2005): 146–55. http://dx.doi.org/10.1177/0361198105194000116.

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Field cores were taken in 1995 and 2002 from eight asphalt pavements constructed in 1993 at FHWA's pavement testing facility to evaluate in situ pavement aging. Dynamic mechanical properties of these cores were evaluated by using the Superpave® shear tester. The moduli of aged pavements were also predicted from binder, aggregate, and mixture properties with available prediction models, and the aging severity levels of all pavements were compared between the lab-measured and model-predicted. Eight pavements with two polymer-modified and six unmodified binders were evaluated in this study. Polymer-modified asphalt pavements showed comparatively lower aging than unmodified asphalt pavements. For unmodified asphalt pavements, stiffer asphalts tended to have higher aging indices. The binder aging index was found to be inversely proportional to the loading frequency, and differences between the aging indices for different binders were higher at lower frequency. Comparison of lab-measured and model-predicted binder aging indices showed similar rankings for all binders. Low stiffness binders, for example, AC-5, showed higher aging indices than high stiffness binders, for example, Styrelf. Pavement depth significantly affected binder aging. The aging index near the surface (6.35 mm) was found to be about four to five times the aging index at a depth of 139.7 mm in pavement. Comparison of lab-measured and model-predicted mixture aging indices showed large variations, from overpredicted to quite underpredicted, depending on the binder type and nominal maximum aggregate size.

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Journal articles on the topic 'Nominal Maximum Aggregate Size'

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