Effect of Prolonged Heating on the Asphalt-aggregate Bond Strength of HMA Containing Liquid Anti-strip Additives

Effect of Prolonged Heating on the Asphalt-aggregate Bond Strength of HMA Containing Liquid Anti-strip Additives PDF Author: Akhtarhusein Asgarali Tayebali
Publisher:
ISBN:
Category : Asphalt concrete
Languages : en
Pages : 96

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Effect of Prolonged Heating on the Asphalt-aggregate Bond Strength of HMA Containing Liquid Anti-strip Additives

Effect of Prolonged Heating on the Asphalt-aggregate Bond Strength of HMA Containing Liquid Anti-strip Additives PDF Author: Akhtarhusein Asgarali Tayebali
Publisher:
ISBN:
Category : Asphalt concrete
Languages : en
Pages : 96

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Effect of Prolonged Heating on the Asphalt-Aggregate Bond Strength of HMA Containing Liquid Anti-strip Additives

Effect of Prolonged Heating on the Asphalt-Aggregate Bond Strength of HMA Containing Liquid Anti-strip Additives PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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ABSTRACT Venkata Lakshman Mandapaka. Effect of prolonged heating on the Asphalt-Aggregate Bond Strength of HMA containing Liquid Anti-strip Additives (Under the direction of Dr. A.A. Tayebali and Dr. Detlef Knappe) In this study, an attempt was made to determine the effect of prolonged heating on the bond strength between aggregate and asphalt that contained anti-strip additive (LOF 6500 of various percentages). A series of tests, namely Tensile Strength Ratio test (TSR), Contact Angle test, Pneumatic Adhesion test and Atomic Force Microscopy (AFM) test were performed, and the results obtained from each of these tests were compared to come to a reliable conclusion regarding effectiveness of the various tests for assessing the effect of prolonged heating on the adhesive bond strength. Results obtained from the Tensile Strength Ratio test showed that, as the prolonged heating duration increased the adhesive strength between the asphalt and aggregate was reduced. These results suggest that the non-volatilized portion of the anti-strip additive that remained in the asphalt after prolonged heating increased the moisture sensitivity of the asphalt-aggregate mixture, increased to the point where the mixtures failed the limiting TSR value of 85% as followed by NCDOT specification. Following the Tensile Strength Ratio test, Contact Angle test and Pull-Off test were performed in anticipation of expecting similar results that were obtained for the Tensile Strength Ratio test. However, due to complex interactions of such parameters as mixing of the anti-strip additive in asphalt cement, cleaning up of the glass/quartz slides, various temperature conditions, etc., the results obtained were inconclusive. Atomic Force Microscopy test was also not observed to be a good test for determination of the adhesive strength between the asphalt-aggregate. Hence, based on the results obtained we recommend that the Contact Angle test, Pull-Off test and Atomic Force Microscopy test are not eff.

Quantify Antitrip Additives in Asphalt Binders and Mixes

Quantify Antitrip Additives in Asphalt Binders and Mixes PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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In this study, litmus and colorimetric tests were developed to quantify the contents of amine-based antistrip additives in asphalt binders and mixes. In addition, the effect of prolonged heating on antistrip additive content was evaluated for both asphalt binders and mixes. Results of this study indicate that both litmus and colorimetric tests are capable of detecting and quantifying amine-based antistrip additives in asphalt binders and mixes. Also, both test methods were able to validate the antistrip additive contents in field samples with known additive contents. When subjected to prolonged heating periods, the antistrip additive content decreased substantially for both asphalt binders and mixes. For asphalt binders, no antistrip additive content was detectable after 24 to 48 hours of extended heating; for mixes, the measured antistrip additive content approached non-detectable level after 6 to 12 hours of extended heating. Tensile Strength Ratio test was conducted in this research to evaluate the effect of prolonged heating on the asphalt-aggregate bond strength of hot mix asphalt (HMA) containing liquid antistrip additives. Improvement of moisture sensitivity by use of amine-based antistrip additive was observed to be lost to a great extent after prolonged heating. It shows that the remaining part of antistrip additive after prolonged heating has reduced effect on adhesion between asphalt and aggregate. The volatilization and⁄or chemical change that occur during the heating process of amine-based antistrip additive affect the improvement of asphalt-aggregate adhesion and ultimately the moisture susceptibility of mixes.

Effect of Prolonged Heating on the Asphalt-aggregate Bond Strength of HMA

Effect of Prolonged Heating on the Asphalt-aggregate Bond Strength of HMA PDF Author: Venkata Lakshman Murthy Mandapaka
Publisher:
ISBN:
Category :
Languages : en
Pages : 97

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Book Description
Keywords: portable adhesion tester, Johnson-Kendell-Roberts, ductility, Tensile strength ratio, Wilhelmy Plate technique, de-ionized, anomalies.

Laboratory Evaluation of Anti-strip Additives in Hot Mix Asphalt

Laboratory Evaluation of Anti-strip Additives in Hot Mix Asphalt PDF Author: Bradley J. Putnam
Publisher:
ISBN:
Category : Asphalt
Languages : en
Pages : 178

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Book Description
The use of hydrated lime or other liquid anti stripping agents (ASA) is the most common method to improve the moisture susceptibility of asphalt mixes. However, most laboratory test conditions used to evaluate the moisture susceptibility of the mixes are only for a short duration of time. This might not be a good representation of the field conditions (i.e., several months or years of service). Thus, a study to evaluate the effects of conditioning the mixes for longer durations was initiated. Also, another problem with the use of the liquid anti stripping agents is their heat storage stability. This report addresses these two issues, by preparing and testing mixtures made with fresh binder for indirect tensile strength after conditioning the samples for 1, 7, 28, 90 and 180 days, and samples prepared from binder stored for three days at 160° C after conditioning them for 1, 28 and 90 days. The results of this study indicated that hydrated lime and the liquid anti stripping agents were equally effective for the mixes used in this research when conditioned beyond one day. In the case of samples prepared from stored binder, there was no significant difference in the effectiveness of hydrated lime and the liquid anti stripping agents even after conditioning for one day. Though it was observed that none of the ASA treatments performed better than others in the case of samples prepared with stored binder, it was also observed that almost all mixes gave significantly similar wet ITS and TSR values as samples prepared from fresh binder.

Effects of Moist Aggregates on the Performance of Warm Mix Asphalt Mixtures Containing Non-Foaming Additives

Effects of Moist Aggregates on the Performance of Warm Mix Asphalt Mixtures Containing Non-Foaming Additives PDF Author: V. S. Punith
Publisher:
ISBN:
Category : Environment friendly asphalt mixture
Languages : en
Pages : 11

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Book Description
The objective was to conduct a laboratory investigation of moisture susceptibility and rutting resistance of non-foaming warm mix asphalt (WMA) mixtures containing moist aggregates. Gyration number and weight loss of various samples, indirect tensile strength (ITS), tensile strength ratio (TSR), rut depths of dry and moisture conditioned specimens, as well as failed temperatures and rutting factors of recovered binders were measured for all mixtures. The experimental design included two aggregate moisture contents (0 and ~0.5 % by weight of the dry mass of the aggregate), two lime contents (1 and 2 % lime by weight of dry aggregate) and one liquid anti-stripping agent (ASA), three non-foaming WMA additives (Cecabase®, Evotherm®, and Rediset®) with control, and two aggregate sources. A total of 34 mixtures were designed and a total of 340 specimens were tested in this study. The test results indicated that the aggregate source significantly affects the ITS and rutting resistance regardless of the WMA additive, ASA, and moisture content. In addition, the ITS and rut depth of the non-foaming WMA mixtures containing moist aggregates generally satisfied the demand of pavement without additional treatment. The mixtures with three WMA additives exhibited similar rutting resistance under dry and wet conditions. The liquid ASA, used in this study, for moisture resistance is not recommended to use in WMA mixtures containing moist aggregates as the aggregate is sensitive to moisture.

Special Mixture Design Considerations and Methods for Warm Mix Asphalt

Special Mixture Design Considerations and Methods for Warm Mix Asphalt PDF Author:
Publisher: Transportation Research Board
ISBN: 0309213738
Category : Science
Languages : en
Pages : 53

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Book Description
TRB's National Cooperative Highway Research Program (NCHRP) Report 714: Special Mixture Design Considerations and Methods for Warm-Mix Asphalt: A Supplement to NCHRP Report 673: A Manual for Design of Hot-Mix Asphalt with Commentary presents special mixture design considerations and methods used with warm-mix asphalt. NCHRP Report 714 is a supplement to NCHRP Report 673: A Manual for Design of Hot-Mix Asphalt. All references to chapters in NCHRP Report 714 refer to the corresponding chapters in NCHRP Report 673.

A Manual for Design of Hot Mix Asphalt with Commentary

A Manual for Design of Hot Mix Asphalt with Commentary PDF Author:
Publisher: Transportation Research Board
ISBN: 0309155649
Category : Asphalt concrete
Languages : en
Pages : 285

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Evaluation of the Roles of Adhesion and Cohesion Properties of Asphalt Binders in Moisture Damage of HMA

Evaluation of the Roles of Adhesion and Cohesion Properties of Asphalt Binders in Moisture Damage of HMA PDF Author: Kunnawee Kanitpong
Publisher:
ISBN:
Category :
Languages : en
Pages : 220

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Characterization of Thermal Degradation of Liquid Amine Anti-Strip Additives in Asphalt Binders Due to RTFO and PAV-Aging

Characterization of Thermal Degradation of Liquid Amine Anti-Strip Additives in Asphalt Binders Due to RTFO and PAV-Aging PDF Author: Nazimuddin M. Wasiuddin
Publisher:
ISBN:
Category : Acids
Languages : en
Pages : 8

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Book Description
In this study, thermal degradation of amine-based liquid anti-strip additives was evaluated due to RTFO-aging and PAV-aging according to AASHTO T 240 and AASHTO R 28 test methods, respectively. The surface free energy (SFE) characteristics of asphalt binders before and after aging were used as a tool for this evaluation. Two asphalt binders, namely PG 64-22 and PG 70-28, and two anti-strip additives, namely AD-Here HP Plus and Redicote E-6, were evaluated. It was observed for 0.75 % AD-Here HP Plus in PG 64-22, mixing at 163°C is more effective than mixing at 145°C with respect to increase in SFE. Also, both RTFO and PAV-aging decrease the total SFE of asphalt binders; both the aging processes are more effective in PG 64-22. In addition, the beneficial effect of anti-strip additives in acid-base characteristics of asphalt binders is severely reduced by RTFO and PAV-aging. Finally, the chemical model of asphalt binder, proposed by Wasiuddin , was expanded to include the SFE characteristics of asphalt binders due to aging.