Effects of liquid antistrip additives on rheology and moisture susceptibility of water bearing warm mixtures

In the asphalt foaming process, the foaming water content (FWC) controls the formation and characteristics of water bubbles. These water bubbles are expected to be expelled from the foamed warm mix asphalt (WMA) during mixing and compaction. However, foaming water may not be completely expelled, rather some of the microbubbles may be trapped in the foamed WMA even after compaction. These microbubbles, or undissipated water, can diffuse over time and cause damage to the foamed WMA. To this end, this study has determined the effects of foaming on the fatigue, moisture damage, and permanent deformation characteristics of foamed WMA. Foamed asphalt and mixtures were designed with varying FWCs and they were tested using linear amplitude sweep, multiple stress creep recovery, four-point flexural beam, and Hamburg wheel tracking tests. Primarily, asphalt foaming dynamics were assessed with a laser-based non-contact method. A simplified viscoelastic continuum damage concept and a three-phase permanent deformation model were used for damage evaluation. The study reveals that foaming softens the binder, which results in slightly higher rutting and moisture susceptibility, though an equivalent or slightly improved fatigue characteristic compared with the regular hot mix asphalt.

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Research on the Performance of Regenerant Modified Cold Recycled Mixture with Asphalt Emulsions

Sustainability ◽

10.3390/su13137284 ◽

2021 ◽

Vol 13 (13) ◽

pp. 7284

Author(s):

Decai Wang ◽

Tengteng Guo ◽

Haolei Chang ◽

Xianhua Yao ◽

Yuanzhao Chen ◽

...

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Dynamic Modulus ◽

Dynamic Mechanical Properties ◽

Moisture Susceptibility ◽

Splitting Strength ◽

Temperature Performance ◽

Strength Tests ◽

Asphalt Emulsions ◽

Coefficient Method

In order to study the mechanical properties and effect of a regenerant on a cold recycled mixture with asphalt emulsions (CRMEs), the moisture susceptibility, high-temperature performance, low-temperature performance, dynamic mechanical properties and durability of CRMEs were analyzed and evaluated by immersion splitting strength tests, freeze-thaw splitting strength tests, rutting tests, semi-circle bending tests, uniaxial compression dynamic modulus tests and indirect tensile tests. Scanning electron microscopy (SEM) was used to analyze the micromorphology of CRMEs modified with regenerant. Finally, a comprehensive evaluation system of five different CRMEs was established based on the efficacy coefficient method to quantitatively analyze the comprehensive performance of the CRMEs. The test results showed that the regenerant can significantly improve the water immersion splitting strength, freeze-thaw splitting strength fracture energy density, and fatigue resistance of CRMEs. However, the addition of regenerant affected the high-temperature performance of the cold recycled mixture. The dynamic modulus of the CRMEs first increased and then decreased with regenerant content increasing. When the regenerant content was 8%, the dynamic modulus of the CRMEs was the highest. Adding styrene-butadiene rubber (SBR) latex can improve the high-temperature performance of CRMEs, but the moisture susceptibility, low temperature performance and fatigue resistance of the cold recycled mixture were not significantly improved, and the dynamic modulus of the mixture was reduced. Based on the efficacy coefficient method, the optimal content of regenerant is 8%. Regenerant are potential modifiers for cold recycled mixture that they can significantly improve the dynamic mechanical properties and durability.

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Performance and Microstructure of Cold Recycled Mixes Using Asphalt Emulsion with Different Contents of Cement

Materials ◽

10.3390/ma12162548 ◽

2019 ◽

Vol 12 (16) ◽

pp. 2548 ◽

Cited By ~ 1

Author(s):

Yanhai Yang ◽

Ye Yang ◽

Baitong Qian

Keyword(s):

Low Temperature ◽

Temperature Stability ◽

Hydration Products ◽

High Temperature Stability ◽

Asphalt Emulsion ◽

Moisture Susceptibility ◽

Pavement Maintenance ◽

Maintenance And Rehabilitation ◽

Low Temperature Cracking ◽

Temperature Crack

Cold recycled mixes using asphalt emulsion (CRME) is an economical and environmentally-friendly technology for asphalt pavement maintenance and rehabilitation. In order to determine the optimum range of cement contents, the complex interaction between cement and asphalt emulsion and the effects of cement on performance of CRME were investigated with different contents of cement. The microstructure and chemical composition of the fracture surface of CRME with different contents of cement were analyzed in this paper as well. Results show that the high-temperature stability and moisture susceptibility of CRME increased with the contents of cement increasing. The low-temperature crack resistance ability gradually increased when the content of cement is increased from 0% to 1.5%. However, it gradually decreased when the content of cement is increased from 1.5% to 4%. Cold recycled mixes had better low-temperature cracking resistance when the contents of cement were in the range from 1% to 2%. The results of microstructure and energy spectrum analysis show that the composite structure is formed by hydration products and asphalt emulsion. The study will be significant to better know the effects of cement and promote the development of CRME.

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Use of accelerated loading equipment for determination of long term moisture susceptibility of hot mix asphalt

International Journal of Pavement Engineering ◽

10.1080/10298430500158984 ◽

2005 ◽

Vol 6 (2) ◽

pp. 125-136 ◽

Cited By ~ 16

Author(s):

Rajib B. Mallick ◽

Robert Pelland ∥ ◽

Frederick Hugo #

Keyword(s):

Hot Mix Asphalt ◽

Moisture Susceptibility

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Performance of Asphalt Mixture Used for Asphalt Treated Base of Perpetual Pavements

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.415-417.1531 ◽

2011 ◽

Vol 415-417 ◽

pp. 1531-1536

Author(s):

Fu Ming Liu ◽

Duan Yi Wang

Keyword(s):

Tensile Strain ◽

Performance Test ◽

Asphalt Mixture ◽

Fatigue Tests ◽

Asphalt Pavements ◽

Moisture Susceptibility ◽

Scale Test ◽

And Performance ◽

Wheel Tracking ◽

Fatigue Endurance

This paper presents the results of laboratory and performance tests for an asphalt treated base (ATB) and mixes developed in this study for perpetual asphalt pavements. Laboratory tests for the mixes included moisture susceptibility, wheel tracking and fatigue tests. The results of performance test indicated that the resistances of the high content binder ATB against moisture and fatigue damage were better than those of the lower one. It was also found from the full scale test sections that the tensile strain values at the bottom of the asphalt layer for the ATB sections were low when the asphalt layer thicknesses of the ATB sections were not thicker than those of the conventional sections. All the tensile strain values measured from the ATB sections were within the fatigue endurance limit of 70 microstrain which is the fatigue criterion of a perpetual asphalt pavement.

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Evaluations of Nano-Sized Hydrated Lime on the Moisture Susceptibility of Hot Mix Asphalt Mixtures

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.174-177.82 ◽

2012 ◽

Vol 174-177 ◽

pp. 82-90 ◽

Cited By ~ 5

Author(s):

Ju Nan Shen ◽

Zhao Xing Xie ◽

Fei Peng Xiao ◽

Wen Zhong Fan

Keyword(s):

Tensile Strength ◽

Experimental Design ◽

Hot Mix Asphalt ◽

Hydrated Lime ◽

Asphalt Mixtures ◽

Indirect Tensile Strength ◽

Moisture Resistance ◽

Strength Ratio ◽

Moisture Susceptibility ◽

Indirect Tensile

The objective of this study was to evaluate the effect of nano-sized hydrated lime on the moisture susceptibility of the hot mix asphalt (HMA) mixtures in terms of three methodologies to introduce into the mixtures. The experimental design for this study included the utilizations of one binder source (PG 64-22), three aggregate sources and three different methods introducing the lime. A total of 12 types of HMA mixtures and 72 specimens were fabricated and tested in this study. The performed properties include indirect tensile strength (ITS), tensile strength ratio (TSR), flow, and toughness. The results indicated that the nano-sized lime exhibits better moisture resistance. Introducing process of the nano-sized lime will produce difference in moisture susceptibility.

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Performance Characterization of Stone Mastic Asphalt using Steel Fiber

Journal of Advanced Industrial Technology and Application ◽

10.30880/jaita.2021.02.02.003 ◽

2021 ◽

Vol 02 (02) ◽

Author(s):

Ekarizan Shaffie ◽

◽

H.A. Rashid ◽

Fiona Shiong ◽

Ahmad Kamil Arshad ◽

...

Keyword(s):

Steel Fiber ◽

Mechanical Performance ◽

Permanent Deformation ◽

Asphalt Mixture ◽

Moisture Susceptibility ◽

Mastic Asphalt ◽

Bitumen Content ◽

Stone Mastic Asphalt ◽

The Stability ◽

Marshall Stability

Stone Mastic Asphalt (SMA) is a gap-graded hot mixture designed to provide higher resistance towards permanent deformation and rutting potential by 30% to 40% more than dense-graded asphalt, due to its stable aggregate skeleton structure. However, compared to other types of hot mix asphalt, SMA unfortunately has some shortcomings in term of its susceptibility towards moisture-induced damage due to its structure and excessive bitumen content in the composition. This research aims to assess the performance of a SMA mixture with steel fiber by enhancing overall stability, abrasion resistance, and, most importantly, moisture susceptibility. This study involved the incorporation of various steel fiber proportions of 0%, 0.3%, 0.5% and 0.7% by the total weight of mixture. The steel fiber modified SMA was made up of 6.0% PEN 60/70 bitumen content. The performance of SMA were evaluated through Marshall stability and flow test, Cantabro loss test and indirect tensile strength test. The results obtained from the testing showed that the incorporation of steel fiber is significantly effective to enhance the resistance towards moisture damage, while increasing the stability and reducing the abrasion loss of SMA mixture, compared to conventional mixture. Overall, it can be concluded that the addition of steel fiber in asphalt mixture specifically SMA, has improved the mechanical performance in the application of asphalt pavement with the optimum steel fiber proportion of 0.3% by the weight of mixture. The developed models between the independent variables and responses demonstrated high levels of correlation. The study found that Response Surface Methodology (RSM) is an effective statistical method for providing an appropriate empirical model for relating parameters and predicting the optimum performance of an asphaltic mixture to reduce flexible pavement failure.

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