Evaluation of moisture susceptibility of hot mix asphalt (original) (raw)
Related papers
Laboratory investigation of moisture susceptibility of long-term saturated warm mix asphalt mixtures
International Journal of Pavement Engineering, 2012
Moisture damage in flexible pavements might cause stripping in asphalt pavements and ultimately result in premature failure. Warm mix asphalt (WMA) technology as a means to decrease the energy consumption and emissions associated with conventional hot mix asphalt production is broadly being used recently. However, the utilisation of the hydrated lime and liquid anti-strip additives in WMA mixtures makes these issues more complicated. The objective of this study was to investigate and evaluate the moisture susceptibility of mixtures containing anti-stripping agents (ASAs) and WMA additives after long-term saturated durations. The experimental design for this study included the utilisations of one binder source (PG 64-22), three ASA additives and control, two WMA additives and hot mix, and three aggregate sources. A total of 36 types of mixtures and 540 specimens were fabricated and tested in this study. The performed properties included indirect tensile strength (ITS), tensile strength ratio, flow and toughness. The results indicated that the aggregate source has an effect on dry ITS and flow values but had no effect on wet ITS, wet flow and toughness values. In addition, hot mixture generally had higher dry and wet ITS values, and there were significant differences in flow and toughness values between hot and warm mixtures. Moreover, the hydrated lime exhibited the best moisture resistance in WMA mixtures; the liquid ASA additives could increase the ITS values of mixtures but exhibited a weak moisture resistance in this study. Furthermore, the storage and saturated duration generally had no effect on ITS values, and statistical analysis results did not show any differences among these mixtures.
Hot mix asphalt (HMA) moisture susceptibility analysis: material loss to mechanical properties
SN Applied Sciences
Numerous studies have been conducted to identify moisture sensitive mixes during mix design by simulating various mechanisms of moisture damage. These methods involve the determination of changes in strength or stiffness of asphalt mixes due to moisture conditioning. The objective of this study is to understand the coupled problem of moisture induced material loss and change in strength/stiffness of the mix. Moisture Induced Stress Tester was used for conditioning samples of a poor and a good performing mixes. This test applies cyclic pressures in the asphalt mix samples through repeated pulses of water. The effluent containing aggregates and binder that were dislodged from the samples during the moisture conditioning process were collected for testing. Both coated and uncoated/fractured aggregates were found in the effluent. The results indicated that the samples with a higher loss of asphalt binder compared to other samples in the investigation during conditioning may exhibit higher tensile strengths, and those with a loss of finer materials, which is indicative of aggregate breakdown, show a lower tensile strength. Both seismic modulus and indirect tensile strength tests were found to be able to differentiate the poor and good performing mixes. For the mixes used in this study, the rate of change in indirect tensile strength during moisture conditioning was found to be strongly correlated to the pre-conditioning modulus of the mix, and a method is suggested for using the threshold values of properties of pre-conditioning mixes for different durations of moisture conditioning during mix design to screen poor mixes in a fast and nondestructive manner. Keywords HMA • Seismic modulus • Indirect tensile strength • Dissolved organic carbon • Moisture induced stress tester • Moisture damage • Loss of aggregates • Loss of asphalt binder * Uma Maheswar Arepalli,
Increasing the Durability of Asphalt Mixture Against Moisture: A Case Study in Iran
Indian Journal of Science and Technology, 2017
Background: Hydrated Lime (HL) has been known as an additive for asphalt mixture durability. It is observed to be the most effective additive when moisture damage becomes one of the most pressing pavement failure modes. Methods: The use of HL is a known technique to increase durability and decrease stripping phenomena in asphalt mixtures. In this research, we intended to study the effect of adding HL, by presenting laboratory examinations on different aggregates using with one percent of HL additive and investigating the changes in some main HMA design factors. Results: Test results have been used in Zanjan-Tabriz highway (section 9), which is the longest freeway of Iran. Texas boiling water test (ASTM D3625) was used as a primary investigation of aggregate trend to stripping and Lottman test (AASHTO T283) for testing the indirect tensile strength of asphalt mixtures. Asphalt Mixture durability against moisture was evaluated by TSR ratio, MRR and fatigue index. Conclusion: Results, wholly, confirmed beneficial effects of HL on asphalt mixture durability and stripping Phenomena, for the samples of this project.
Moisture Susceptibility on Asphalt Mix and the Effect of Anti-Stripping Additives
2017
The damage due to moisture can be result in asphalt pavements either due to stripping or the softening of asphalt, both of which result in loss of ability to resist traffic- induced stresses which is mainly occur due to the loss or destruction of bond between the aggregate and the asphalt. This study is aimed to determine the effect of moisture on different graded bitumen mixture i:e open graded mixture and dense graded mixture and the effect of anti-stripping agent(lime) in hot mix asphalt(HMA). Moisture susceptibility of asphalt mixture can be determined by different tests indirect tensile strength test, Retained Marshall stability value and boiling water test with varying the percentage of lime content from 0% to 2.5%.The results indicates that the addition of hydrated lime increases the moisture resistance value to some extent and also provide larger strength as compare to the other mixes without addition of lime and more over the dense graded mix provide more effective value th...
Transportation and Development Institute Congress 2011, 2011
Moisture damage in flexible pavements might cause stripping in the asphalt pavement and ultimately lead to premature failure. In addition, rising energy prices, global warming, and more stringent environmental regulations have resulted in an interest in warm mix asphalt (WMA) technologies as a mean to decrease the energy consumption and emissions associated with conventional hot mix asphalt production. In this study, the objective was to conduct a laboratory investigation of long-term influence of anti-stripping additives on moisture damage in WMA mixtures. The test results indicated that the aggregate source did not show a remarkable effect on moisture susceptibility of mixture in this study. The addition of anti-stripping additives increased the ITS, TSR, and flow values; however, the differences were not statistically significant compared to the control mixtures. Mixtures containing Asphamin® did not perform as well as others. In addition, an increase of condition duration decreases the anti-stripping resistance regardless of mixture type.
The effect of hydrated lime addition in improving the moisture resistance of hot mix asphalt (HMA)
IOP conference series, 2020
It is desirable to have pavement surfaces that last until its designed life. Ravelling, rutting, and potholes are one the pavement failures that are commonly found and those failures are related to the intrusion of moisture onto the asphaltic mixture. This research aims to study the usage of hydrated lime as an additive to improve the moisture susceptibility of the asphaltic mixture. There were two different natural aggregates used in this research project and the prepared specimens were tested by Marshall, Cantabro Loss, and Indirect Tensile Strength tests. From the research results, it was found that hydrated lime was effective in not only improving the moisture susceptibility of the asphaltic mixture, but also increasing the stability and making the asphalt specimens denser. It was also found that it is critical to choose the suitable aggregate to be used in the asphaltic mixture as it can significantly affect the quality of the asphalt specimens.
Effect of asphalt film thickness on the moisture sensitivity characteristics of hot-mix asphalt
Building and Environment, 2007
Temperature, air and water are the common factors that profoundly affect the durability of asphalt concrete mixtures. In mild weather conditions, distresses such as permanent deformation, fatigue cracking can be encountered on the pavements due to traffic loading. But when a severe climate is in question, these stresses increase in poor materials; under inadequate control; with traffic as well as with water which are key elements in the degradation of asphalt concrete pavements. Many variables affect the amount of water damage in asphalt concrete layer. Among them, mixture design properties such as air void level, permeability, asphalt content and asphalt film thickness are the ones that must be investigated carefully. This study is aimed to determine the relationship between the various asphalt film thicknesses and the susceptibility characteristics to water of hot mix asphalt (HMA) so that an optimum asphalt film thickness that minimizes the moisture damage of HMA can be obtained. For this purpose, the modified Lottman Test (AASHTO T283) is performed on the Superpave Gyratory compacted specimens that contain 5 different asphalt film thicknesses. A good correlation between the asphalt film thickness and the modified Lottman test results as well as an optimum asphalt film thickness of 9.5-10.5 mm is obtained.
THE EFFECT OF AGGREGATES QUALITY ON MOISTURE SUSCEPTIBILITY OF HOT MIX ASPHALT
IAEME PUBLICATION, 2020
Aggregates make up the most of total volume of hot mix asphalt, and hence, it is necessary to ensure that the aggregates used were suitable for the asphaltic mixture. The objective of this study is to evaluate the effect of using different aggregates on asphaltic mixture with additional of two different anti-stripping agents, namely 2% hydrated lime and 0.5% Wetbond-SP, to assess the moisture susceptibility of the asphaltic mixture. There were three laboratory tests conducted, which are Marshall, Cantabro Loss, and Indirect Tensile Strength tests and there were three natural aggregates used in this study. From the research results, it was found that adding hydrated lime and Wetbond-SP could improve the stability of the specimens constructed with Aggregate B and Aggregate, but not with Aggregate A. Based on the Cantabro Loss and the ITS tests, it could be concluded that Wetbond-SP was more effective to improve the moisture susceptibility of the asphaltic mixture regardless of which aggregate was used, than the hydrated lime
Effects of various additives on the moisture damage sensitivity of asphalt mixtures
Construction and Building Materials, 2005
Effects of four additives, namely two fatty amine (Wetfix I, Lilamin VP 75P), one catalyst (Chemcrete) and a polymer (rubber), on the moisture damage of asphalt mixtures were studied. Rheological characteristics of the binders were measured using conventional methods both original and thin-film oven aged. Mechanical characteristics of the mixtures were evaluated with Marshall, indirect tensile and Lottman treatment tests. The additives used in this study reduced the level of damage due to moisture in asphalt mixtures. Minimum acceptable indirect tensile strength ratio (0.70) is achieved when Chemcrete and 0.2% of Wetfix I, and 0.4-0.6% of Lilamin VP 75P are used in asphalt mixtures. Indirect tensile strength ratio may decrease due to the relatively higher strength obtained in dry specimens with respect to the conditioned ones. Indirect tensile strength ratios of asphalt paving specimens were found to be less than the Marshall Stability ratios.
Moisture susceptibility assessment of hydrated lime modified asphalt mixture and surface energy
International Journal of Pavement Engineering, 2020
The influence of hydrated lime on moisture susceptibility of asphalt mixture was assessed using a combination of surface energy measurements and modified saturation ageing and tensile stiffness (SATS) test. Four aggregate types, which are commonly used for manufacturing asphalt mixtures in the UK have been selected with 40/60 penetration grade bitumen. These aggregates were from various rocks across the UK which includes felsic intrusive, calcite sedimentary, mafic extrusive and argillaceous sandstone rock sources. Two out of four aggregate sources including felsic intrusive, and argillaceous sandstone showed improvement with the hydrated lime replacement considering results from both surface free energy measurements and modified SATS test, but the performance of aggregates from calcite sedimentary, mafic extrusive rocks remained unaffected. Mineralogical testing of the aggregates, using MLA, showed considerable differences between four aggregate types used in this study. Minerals such as albite, epidote, quartz and chlorite were found predominate in aggregates from felsic intrusive, and argillaceous sandstone sources. Aggregates from calcite sedimentary rock were found abundant in calcite mineral while Argillaceous sandstone aggregates were found rich in chlorite and albite. The difference in the behaviour of four aggregate types to the HL replacement can be credited in part to mineralogical composition of different aggregates. The hydrated lime content of 1% was observed better than 2% in the aggregates who showed improved performance with the use of HL. The trends obtained in the surface energy measurements have been found similar to SATS technique. The results clearly illustrate a close agreement between both techniques used in this study for the evaluation of moisture susceptibility. A comparison between ITSM and ITS test after SATS conditioning was also undertaken as some researchers believe that ITS being destructive in nature gives more distinctive results. But the results of ITSM and ITS very found very similar to each other after SATS conditioning in terms of retained strength or retained stiffness.