Laboratory and Field Evaluation of Warm Mix Asphalt Technology to Determine Its Applicability for Massachusetts PDF Download

Author: Walaa S. Mogawer
Publisher:
ISBN:
Category : Pavements
Languages : en
Pages : 89

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Author: Alexander Jordan Austerman
Publisher:
ISBN:
Category :
Languages : en
Pages : 190

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Author: Abdulaziz Alossta
Publisher:
ISBN:
Category : Asphalt concrete
Languages : en
Pages : 98

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A recent joint study by Arizona State University and the Arizona Department of Transportation (ADOT) was conducted to evaluate certain Warm Mix Asphalt (WMA) properties in the laboratory. WMA material was taken from an actual ADOT project that involved two WMA sections. The first section used a foamed-based WMA admixture, and the second section used a chemical-based WMA admixture. The rest of the project included control hot mix asphalt (HMA) mixture. The evaluation included testing of field-core specimens and laboratory compacted specimens. The laboratory specimens were compacted at two different temperatures; 270 °F (132 °C) and 310 °F (154 °C). The experimental plan included four laboratory tests: the dynamic modulus (E*), indirect tensile strength (IDT), moisture damage evaluation using AASHTO T-283 test, and the Hamburg Wheel-track Test. The dynamic modulus E* results of the field cores at 70 °F showed similar E* values for control HMA and foaming-based WMA mixtures; the E* values of the chemical-based WMA mixture were relatively higher. IDT test results of the field cores had comparable finding as the E* results. For the laboratory compacted specimens, both E* and IDT results indicated that decreasing the compaction temperatures from 310 °F to 270 °F did not have any negative effect on the material strength for both WMA mixtures; while the control HMA strength was affected to some extent. It was noticed that E* and IDT results of the chemical-based WMA field cores were high; however, the laboratory compacted specimens results didn't show the same tendency. The moisture sensitivity findings from TSR test disagreed with those of Hamburg test; while TSR results indicated relatively low values of about 60% for all three mixtures, Hamburg test results were quite excellent. In general, the results of this study indicated that both WMA mixes can be best evaluated through field compacted mixes/cores; the results of the laboratory compacted specimens were helpful to a certain extent. The dynamic moduli for the field-core specimens were higher than for those compacted in the laboratory. The moisture damage findings indicated that more investigations are needed to evaluate moisture damage susceptibility in field.

Author: Clinton Isaac Van Winkle
Publisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages : 39

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Currently in Iowa, the amount of RAP materials allowed for the surface layer is limited to 15% by weight. The objective of this project was to develop quality standards for inclusion of RAP content higher than 15% in asphalt mixtures. To meet Superpave mix design requirements, it was necessary to fractionate the RAP materials. Based on the extensive sieve-by-sieve analysis of RAP materials, the optimum sieve size to fractionate RAP materials was identified. To determine if the higher percentage of RAP materials than 15% can be used in Iowa's state highway, three test sections with 30.0%, 35.5% and 39.2% of RAP materials were constructed on Highway 6 in Iowa City. The construction of the field test sections was monitored and the cores were obtained to measure field densities of test sections. Field mixtures collected from test sections were compacted in the laboratory in order to test the moisture sensitivity using a Hamburg Wheel Tracking Device. The binder was extracted from the field mixtures with varying amounts of RAP materials and tested to determine the effects of RAP materials on the PG grade of a virgin binder. Field cores were taken from the various mix designs to determine the percent density of each test section. A condition survey of the test sections was then performed to evaluate the short-term performance.

Author: Zhanping Yuo
Publisher:
ISBN:
Category : Asphalt emulsion mixtures
Languages : en
Pages : 0

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Hot Mix Asphalt (HMA) has been traditionally produced at a discharge temperature of between 280° F (138° C) and 320° F (160° C), resulting in high energy (fuel) costs and generation of greenhouse gases. The goal for Warm Mix Asphalt (WMA) is to use existing HMA plants and specifications to produce quality dense graded mixtures at significantly lower temperatures. Europeans are using WMA technologies that allow the mixture to be placed at temperatures as low as 250° F (121° C). It is reported that energy savings on the order of 30%, with a corresponding reduction in CO2 emissions of 30%, are realized when WMA is used compared to conventional HMA. Although numerous studies have been conducted on WMA, only limited laboratory experiments are available and most of the current WMA laboratory test results are inconsistent and not compatible with field performance The main objectives of this study are: The main objectives of this study are: 1) review and synthesize information on the available WMA technologies; 2) measure the complex/dynamic modulus of WMA and the control mixtures (HMA) for comparison purpose and for use in mechanistic-empirical (ME) design comparison; 3) assess the rutting and fatigue potential of WMA mixtures; and 4) provide recommendation for the proper WMA for use in Michigan considering the aggregate, binder, and climatic factors. The testing results indicated that most of the WMA has higher fatigue life and TSR which indicated WMA has better fatigue cracking and moisture damage resistant; however, the rutting potential of most of the WMA tested were higher than the control HMA. In addition, the WMA design framework was developed based on the testing results, and presented in this study to allow contractors and state agencies to successfully design WMA around the state of Michigan.

Author: Fan Yin
Publisher:
ISBN:
Category :
Languages : en
Pages : 74

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Warm-Mix Asphalt (WMA) refers to the asphalt concrete paving material produced and placed at temperatures approximately 50°F lower than those used for Hot-Mix Asphalt (HMA). Economic, environmental and engineering benefits have boosted the use of WMA technology across the world during the past decade. While WMA technology has been successfully utilized as a paving material, several specifications and mix design protocols remain under development. For example, currently, there is no consistent laboratory conditioning procedure for preparing WMA specimens for performance tests, despite being essential for mix performance. Based on previous studies, several candidate conditioning protocols for WMA Laboratory Mixed Laboratory Compacted (LMLC) and off-site Plant Mixed Laboratory Compacted (PMLC) specimens were selected, and their effects on mixture properties were evaluated. Mixture stiffness evaluated in a dry condition using the Resilient Modulus (MR) test (ASTM D-7369) was the main parameter used to select a conditioning protocol to simulate pavement stiffness in its early life. The number of Superpave Gyratory Compactor (SGC) gyrations to get 7±0.5% air voids (AV) was the alternative parameter. Extracted binder stiffness and aggregate orientation of field cores and on-site PMLC specimens were evaluated using the Dynamic Shear Rheometer (DSR) (AASHTO T315) and image analysis techniques, respectively. In addition, mixture stiffness in a wet condition was evaluated using the Hamburg Wheel-Track Test (HWTT) (AASHTO T324) stripping inflection point (SIP) and rutting depth at a certain number of passes. Several conclusions are made based on test results. LMLC specimens conditioned for 2 hours at 240°F (116°C) for WMA and 275°F (135°C) for HMA had similar stiffnesses as cores collected during the early life of field pavements. For off-site PMLC specimens, different conditioning protocols are recommended to simulate stiffnesses of on-site PMLC specimens: reheat to 240°F (116°C) for WMA with additives and reheat to 275°F (135°C) for HMA and foamed WMA. Additionally, binder stiffness, aggregate orientation, and overall AV had significant effects on mixture stiffness. Mixture stiffness results for PMFC cores and on-site PMLC specimens in a wet condition as indicated by HWTT agree with those in a dry condition in MR testing. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148143

Author: Haritha Malladi
Publisher:
ISBN:
Category :
Languages : en
Pages : 100

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Author: Nathan Bower
Publisher:
ISBN:
Category : Asphalt concrete
Languages : en
Pages : 111

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Author: Zhanping Yuo
Publisher:
ISBN:
Category : Asphalt emulsion mixtures
Languages : en
Pages : 108

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Book Description
Hot Mix Asphalt (HMA) has been traditionally produced at a discharge temperature of between 280° F (138° C) and 320° F (160° C), resulting in high energy (fuel) costs and generation of greenhouse gases. The goal for Warm Mix Asphalt (WMA) is to use existing HMA plants and specifications to produce quality dense graded mixtures at significantly lower temperatures. Europeans are using WMA technologies that allow the mixture to be placed at temperatures as low as 250° F (121° C). It is reported that energy savings on the order of 30%, with a corresponding reduction in CO2 emissions of 30%, are realized when WMA is used compared to conventional HMA. Although numerous studies have been conducted on WMA, only limited laboratory experiments are available and most of the current WMA laboratory test results are inconsistent and not compatible with field performance The main objectives of this study are: The main objectives of this study are: 1) review and synthesize information on the available WMA technologies; 2) measure the complex/dynamic modulus of WMA and the control mixtures (HMA) for comparison purpose and for use in mechanistic-empirical (ME) design comparison; 3) assess the rutting and fatigue potential of WMA mixtures; and 4) provide recommendation for the proper WMA for use in Michigan considering the aggregate, binder, and climatic factors. The testing results indicated that most of the WMA has higher fatigue life and TSR which indicated WMA has better fatigue cracking and moisture damage resistant; however, the rutting potential of most of the WMA tested were higher than the control HMA. In addition, the WMA design framework was developed based on the testing results, and presented in this study to allow contractors and state agencies to successfully design WMA around the state of Michigan.

Author: Jianhua Yu
Publisher:
ISBN:
Category : Asphalt concrete
Languages : en
Pages : 8

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Warm mix asphalt (WMA) technology provides sufficient workability for asphalt mixtures at reduced mixing and compaction temperatures. Depending on the WMA technology, the typical temperature reduction range is 20 °C to 55 °C below hot mix asphalt (HMA) production temperatures. WMA involves chemical and wax additives that are added to an asphalt binder or incorporated through the use of foaming technology. The main advantages of WMA are reduced emissions and a reduction in combustible fuel consumption. Ongoing WMA research projects have documented some differences between HMA and WMA mixes, prompting numerous research projects that are investigating these concerns. The purpose of this research is to evaluate the volumetric properties by directly comparing laboratory produced WMA and HMA mixes. This study investigates the impact of WMA additives on the volumetric properties, specifically, the theoretical maximum specific gravity (Gmm). The Gmm testing followed the procedure of ASTM D2041. Two mix designs with HMA binder were produced, one without recycled asphalt pavement (RAP) and the other with 30 % RAP. After the mix designs were completed, no additional changes were made to account for the addition of the WMA technology. The mixes included the WMA technologies Sasobit and Advera, as well as an HMA control, for a total of six different laboratory produced mixes. Each mix was produced at 120 °C, 135 °C, and 150 °C, and each mix was oven cured for 1, 2, and 4 h. The test results were analyzed using statistical principles to determine whether differences in the Gmm values were statistically significant. The results show that temperature has little impact on Gmm. Gmm was not affected by curing times of 1 and 2 h, but the longer curing time of 4 h resulted in a statistically significant increase in Gmm. Further analysis revealed that the mix sensitivity to curing time depends on the amount of RAP in the mix. For the mix designs studied, the Advera Gmm values were similar to the HMA values, but the Sasobit Gmm values were statistically lower than the Advera values.