Moisture Susceptibility Of Asphalt Mixtures Research Articles

Evaluation the Rheological Behavior of Asphalt Binder, Fracture Resistance and Moisture Susceptibility of Asphalt Mixtures: Before and After Adding Nano Fe2O3

Evaluation the Rheological Behavior of Asphalt Binder, Fracture Resistance and Moisture Susceptibility of Asphalt Mixtures: Before and After Adding Nano Fe2O3

Analysis of performance parameters based on surface free energy to evaluate moisture susceptibility of asphalt mixtures modified with calcined marl dust

ABSTRACT This study investigates the impact of calcined marl dust (CMD) on moisture susceptibility in asphalt mixtures with limestone and granite aggregates. The surface free energy (SFE) method and Hamburg wheel tracking test were used to assess this influence. Bitumen was mixed with various CMD percentages (0%, 10%, 25%, 40%) to analyze adhesion work, debonding work, and wettability. Results were utilized for energy ratios (ER1 and ER2) to gauge moisture susceptibility, while rut depth ratio (RDR) analysis was also conducted for these mixtures. The study found that higher aggregate total SFE correlated with decreased ER1 and ER2 values, showing strong correlation (R2 of 0.7974 for ER1 and 0.6572 for ER2) with RDR. At the optimal CMD content of 25%, the modified asphalt mix with limestone aggregate showed a 35% improvement in ER1 and a 21.6% enhancement in ER2, signifying improved moisture resistance.

Evaluating the Moisture Susceptibility of Asphalt Mixtures Containing Aluminum Dross as a Filler

One of the most essential components of asphalt pavements is the filler. It serves two purposes. First, this fine-grained material (diameter less than 0.075 mm) improves the cohesiveness of aggregate with bitumen. Second, produce a dense mixture by filling the voids between the particles. Aluminum dross (AD), which is a by-product of aluminum re-melting, is formed all over the world. This material causes damage to humans and the environment; stockpiling AD in landfills is not the best solution. This research studies the possibility of replacing part of the conventional filler with aluminum dross. Three percent of dross was used, 10, 20, and 30% by filler weight. The MarshallMix design method was adopted to obtain the optimum asphalt content for the selected aggregate gradation. After that, the mixture was used to evaluate the moisture damage for controlandimproved mixtures. The compressive strength and tensile strength tests were used to estimate the moisture damage to the asphalt mixtures. It was observed that replacing a part of the limestone dust filler with aluminum dross would improve moisture damage resistance. This was approved since the maximum increase in tensile strength ratio (TSR)was found to be 13.42% at 20% of AD, and the maximum increase in the index of retained strength (IRS)was found to be 8.73% at the same AD percent.

Evaluating the Moisture Susceptibility of Asphalt Mixtures Containing RCA and Modified by Waste Alumina

The management of building and demolition waste is an important subject in the government's sustainability efforts. Today, recycling and reusing industrial waste and by-products is a topic of considerable relevance in every industry, but it is especially important in cement and concrete technology. Within the asphalt pavement sector, the necessity for environmentally friendly highway design and construction is at the top of the priority list. Nevertheless, due to the inferior behavior of the resulting recycled concrete aggregate (RCA) mixes, additional enhancement materials are needed. In this study, the effect of using alumina waste in the form of secondary aluminum dross (SAD) in the asphalt compacted specimens that contained RCA as coarse aggregate was discussed. The conventional limestone dust filler is replaced by SAD at rates of 10, 20, and 30% by filler weight in the control mix, and then the best percentage is used in mixtures containing RCA at rates of 25, 50, 75, and 100%. The experimental work includes volumetric properties by employing the Marshall design method, indirect tensile strength (ITS), and compressive strength. All the used percent of SAD enhanced the properties of the asphalt mixture; the tensile strength ratio (TSR) of the control mixture increased by 4.58%, 8.52%, and 7.64% for SAD rates (10, 20, and 30%), respectively. The best dosage of SAD was added to the mixture containing RCA at different specified rates. The maximum TSR (13.92%) was obtained at 25% RCA. The same steps were followed in the compressive strength test; adding SAD increased the index of retained strength (IRS) of the control mixture by 55.11, 13.42, and 9.13% for 10, 20, and 30%, respectively. Thereafter, the best dosage of 20% SAD was added to the hot mix asphalt (HMA) containing different RCA percents. The maximum IRS (17.43%) was also obtained at a 25% RCA. Doi: 10.28991/CEJ-SP2023-09-019 Full Text: PDF

Recycling flue gas desulfurization ash in enhancing the comprehensive moisture susceptibility of asphalt mixtures

Moisture susceptibility of asphalt mixtures is a major concern in areas with heavy rainfall or humid climates, as it can lead to premature pavement failures. As a typical industrial by-product during the flue gas desulfurization process of coal-fired, flue gas desulfurization ash (FGDA) with alkali mineral can facilitate the water damage resistance of asphalt mixtures. However, low density and high hydrophilic coefficient of FGDA limit its improvement effect. Hence, the comprehensive moisture susceptibility of asphalt mixtures with FGDA deserves systematic investigation. In this study, the properties indexes of FGDA and FGDA-limestone filler (LF) composite fillers were characterized. And the moisture susceptibility of asphalt mixtures containing six dosages of FGDA-LF fillers under hydrostatic damage and moisture induced sensitivity tester (MIST) hydrodynamic damage conditions were determined. The comprehensive assessment index of FLAM was explored based on radar chart assessment mean. The results indicate that FGDA with high alkali minerals and flocculent sphere morphology promotes the improvement of dispersivity and compatibility and the generation of homogeneous integral structure. Incorporating FGDA in FGDA-LF composite filler degrades its apparent density and elevates fineness and hydrophilic coefficient. Under MIST hydrodynamic damage, FLAM demonstrates the larger RMS and TSR than asphalt mixture with LF, accompanied by smaller attenuation compared to hydrostatic treatment. FLAM with F3 reveals the lowest rutting depth of 8.65 mm and creep slope of 1.92 × 10−4 and the largest comprehensive assessment index of 0.9998, indicating its optimal comprehensive moisture susceptibility. It is suggested that 30% FGDA might be an appropriate substitution amount for LF in FLAM.

Moisture Susceptibility of Asphalt Mixture Subjected to Chloride-Based Deicing Salt Solutions under Simulated Environmental Conditions

Moisture Susceptibility of Asphalt Mixture Subjected to Chloride-Based Deicing Salt Solutions under Simulated Environmental Conditions

The Impact of Nano-TiO2 Particles on the Moisture Susceptibility and Fracture Toughness of HMA under Mixed-Mode I/II Loading and Various Crack Geometry and Temperatures

In recent decades, some of the main goals of pavement engineers have been to increase bearing capacity, enhance tensile strength, and improve the moisture susceptibility of asphalt mixtures. Because moisture and frost intensify the damage caused by traffic loads on pavements in cold climates, the life and safety of asphalt pavements in this climate are reduced. Finally, cracking at low temperatures and moisture damage leads to a decrease in the serviceability of asphalt pavement in cold climates relative to temperate climates. Hence, a comprehensive and accurate program is necessary to estimate the fracture toughness and moisture susceptibility of asphalt mixtures in cold climates. In recent years, nanotechnology has become very popular due to its unique features in enhancing the operation of bitumen and asphalt mixtures. For this purpose, in this study, the impact of nano-TiO2 on pavement performance against cracking and moisture susceptibility is investigated. To achieve this objective, SCB specimens were fabricated with different ratios of nano-TiO2 (0.0% and 0.9%) and studied at the three temperatures of −5°C, −15°C, and −25°C under pure mode I, pure mode II, and four distinct mixed-mode (I/II) loading (Me=0.2, Me=0.4, Me=0.6, Me=0.8) for various crack geometry, including vertical and angular cracks for which the crack angle is 45° in samples with angular cracks. In addition, the indirect tensile strength (ITS) test was employed to estimate the moisture susceptibility. The results indicated that modifying the asphalt mixture properties with 0.9% nano-TiO2 had a significant impact on the fracture behavior of the samples in both vertical and angular cracks under all temperatures. Additionally, with the application of nano-TiO2 and decreasing temperature, the fracture toughness of the samples increased. Furthermore, the findings displayed that the employment of 0.9% nano-TiO2 reduced the moisture susceptibility of asphalt mixtures by approximately 6%.

Moisture Susceptibility of Asphalt Mixtures: Conditioning and Testing Protocols

Moisture damage is a common distress in asphalt pavements caused by infiltrated moisture, which degrades mixture strength and affects pavement durability. Loaded wheel tracking (LWT) and modified Lottman (ML) tests are the two commonly used mechanical tests for assessing the moisture susceptibility of asphalt mixtures, but they have been reported to show limitations in consistently ascertaining the moisture sensitivity of different asphalt mixtures under field conditions. This study evaluated the effectiveness of different laboratory mechanical tests (LWT, ML, and semi-circular bend [SCB]) in ascertaining moisture sensitivity of asphalt mixtures. LWT, ML, and SCB tests were conducted on asphalt mixtures prepared with two asphalt binders (an unmodified PG 67-22 and a styrene-butadiene-styrene polymer-modified PG 70-22) and three aggregate types (limestone, crushed gravel, and semi-crushed gravel). Before testing, asphalt binder and mixture samples were exposed to five moisture conditioning levels: (1) unconditioned (dry), (2) single freeze-thaw cycle, (3) triple freeze-thaw cycle, (4) moisture induced stress tester (MiST) 3,500 cycles, and (5) MiST 7,000 cycles. A multiple stress creep recovery test was conducted on asphalt binders subjected to the five moisture conditioning levels. Results showed that the stress sensitivity of asphalt binders decreased after freeze-thaw and MiST conditioning. LWT rut depth and a new parameter which was developed as part of the study, SCB Jd ratio, were found to capture the progressive moisture damage in asphalt mixtures associated with different moisture conditioning levels. Mixtures containing PG 70-22 asphalt binder exhibited better moisture damage resistance compared with mixtures containing PG 67-22 asphalt binder.

Moisture Damage Characterization of Rubber-Modified Asphalt Mixture Containing Waste Steel Slag under Multiple Freeze–Thaw Cycles

Recycling waste materials has become popular in the pavement industry because of its potential for significant environmental benefits, conservation of natural resources, and sustainability. This study investigated the feasibility of simultaneously recycling waste steel slag and tire rubber in bituminous pavements and analyze the moisture susceptibility of asphalt mixtures made of these solid wastes. The physical and chemical characteristics of the aggregates and the adhesive behavior of the aggregate–bitumen system were explored to determine their impact on moisture sensitivity. Accordingly, two different methods, freeze–thaw splitting test and fracture energy tests, were employed to assess the moisture stability of mixes in a multiple freeze–thaw environment. The microstructure of the interface between the aggregate and bitumen was investigated, and the long-term moisture damage process of the mixes was clarified and verified. The results indicate that the natural hyperalkalinity and porous structure of the steel slag have a favorable effect on the adhesion performance. Cohesive failure was found to be the primary mode of failure of loose asphalt mixtures in a multiple freeze–thaw environment. We tentatively propose that the adhesion energy loss is a secondary failure mode of the loose asphalt mixtures. The addition of 100% steel slag and asphalt rubber had the greatest impact on improving the long-term moisture resistance of the asphalt mixtures. The present work is beneficial for the practical application of waste tire rubber and steel slag in highway engineering.

Evaluation of Moisture Susceptibility of Asphalt Mixtures: Influence of Aggregates, Visual Analysis, and Mechanical Tests

Asphalt pavement failure is directly related to the traffic and climate effects. Temperature and moisture severely impact pavement service life. It is known that moisture changes the stiffness and stress–strain distribution and all the mechanical behaviors of the mixture/structure. There is a huge interest in studying the impact of water on the behavior of flexible pavements, mainly on freeze–thaw regions under tropical climates with high rainfall levels. The scope of the present paper was to check the susceptibility to moisture-induced damage of dense asphalt mixes produced and applied on highways in Brazil’s southernmost region using different laboratory tests: visual adhesion of coarse aggregate; tensile strength ratio (TSR), and dynamic modulus ratio (DMR). Thus, this study evaluated the morphological, chemical, and mineralogical properties of aggregates from 11 quarries, as well as the interaction between aggregates and the respective bituminous binders. Rocks with high Si contents performed worse in visual adhesiveness tests; chemical ratios such as Fe/Si above 1 and Ca/K above 5, as well as the rougher texture of aggregates, considerably improved the coating, reducing the failures in adhesion. Results of TSR and DMR, after applying the induced moisture damage cycle, indicated greater susceptibility to conventional binders than mixtures containing modified binders in their composition. The action of moisture damage for most mixtures caused a reduction in strength and stiffness, warning of a decrease in the binder’s ability within the mixture, completely changing the distribution of efforts within the structure. Therefore, from this study, it is possible to suggest using DMR instead of TSR to assess susceptibility to moisture damage.

Moisture susceptibility of waste ceramic tiles modified asphalt mixtures

Waste ceramic tiles have been recognized as viable in producing asphalt mixtures. However, the primary concern is the assurance of its durability, especially in terms of moisture damage. Therefore, this research aims to investigate the moisture susceptibility of asphalt mixtures incorporating waste ceramic tiles (WCT). The coarse aggregates of 25 mm size were partially replaced with WCT at 0%-50% proportions. The Marshall Method of mix design was used to calculate the optimum bitumen content (OBC) at various levels of WCT replacement. Utilizing the retained strength index (RSI) and tensile strength ratio (TSR) tests, the moisture susceptibility of the mixes compacted at OBC was assessed. The results indicate that the continuous increase of WCT leads to decreased TSR and RSI values. The RSI ranges from 91.10%-81.90%, 74.91%-61.07% and 47.89%-41.05% at 1, 3, and 7-day curing, respectively. The TSR ranges from 89.27-74.73%, 71.48-63.81% and 58.02-46.79% at 1, 3, and 7-day curing, respectively. Nevertheless, it was determined that the WCT-modified asphalt mixtures met the TSR and RSI standards for asphalt mixtures with satisfactory moisture resistivity performance at 1 and 3 days of curing. For satisfying performance of WCT-modified asphalt mixtures, the study recommends an optimum proportion of 30% WCT.

Measuring moisture damage of hot-mix asphalt (HMA) by digital imaging-assisted modified boiling test (ASTM D3625): Recent advancements and further investigation

Boiling water test (ASTM D3626) has been utilized to investigate the moisture susceptibility of asphalt mixture for decades. It was originally intended to compare the relative moisture resistance of a few mixtures, and the degree of stripping after the boiling was recorded based on visual observations. In recent years, several digital imaging-assisted modified boiling tests have been proposed, which significantly improved the accuracy of test results. This paper reviewed the recent advancements (2009–2022) in different test methods by digital imaging. The limitations and challenges of each method were also discussed and compared to each other. In addition, further experiments were performed to investigate the effect of aging, boiling time and water quality on the coating ratios. The boiling test results of sixty loose mixtures were compared to the tensile strength ratios (TSRs). Based on the results, the boiling water test with enhanced accuracy by image processing can be potentially developed as a measure of field performance. More importantly, the test should be conducted immediately after the mixing of asphalt and aggregate, and the aging of asphalt mixtures could significantly increase the results of coating ratios up to 100%, which made the boiling test unable to identify moisture susceptibility. It was found that the boiling water could not strip asphalt from aggregate after a long time of aging even though the moisture damage occurred and weakened the bond between asphalt and aggregate. In addition, the water quality could considerably influence the boiling test results, and the use of distilled water might underestimate the moisture damage of asphalt mixtures subjected to acid rain.

Laboratory investigation on pavement performance of indirect coal liquefaction residue in asphalt mixture

Indirect coal liquefication residue (ICLR) is a by-product of coal-to-liquid technology, which is harmful to the ecological environment and human health. In this study, an innovative method of using ICLR to replace limestone fine aggregate in asphalt mixture was proposed to solve the disposal problem of ICLR. A traditional and seven different ICLR contained asphalt mixtures were designed and tested to evaluate whether ICLR can be recycled as a kind of pavement material . Firstly, XRD and FTIR were employed to characterize the chemical composition of ICLR to gain insight into the advantages of using ICLR as fine aggregate. Then, asphalt mixture performance including rutting resistance , low-temperature cracking resistance , and moisture susceptibility was tested on the above-mentioned eight kinds of mixtures to evaluate the impact of ICLR particle size effect and replacement amount. The results demonstrate that using ICLR to only replace one group of three groups of aggregates (0.6–1.18 mm, 1.18–2.36 mm, and 2.36–4.75 mm), the performance of asphalt mixture was better than replacing two or three groups at the same time. It was found that replacing limestone aggregate with ICLR improved the high-temperature performance and moisture susceptibility of the asphalt mixture. The use of ICLR instead of aggregate did not improve the low-temperature performance, or even slightly reduce it, but it still met the specification requirements through reasonable replacement. Finally, the gradation filling theory and asphalt film thickness confirmed the possibility of using ICLR instead of fine aggregate. Therefore, it is concluded that using ICLR in asphalt mixture instead of fine aggregate provides a reliable and value-added solution to recycle ICLR. • ICLR could replace limestone fine aggregate in asphalt mixture to solve its disposal problem. • A reasonable ICLR replacement plan could improve the rutting resistance and moisture susceptibility of asphalt mixture. • The gradation filling theory proved the feasibility of replacing fine aggregate with ICLR, along with asphalt film thickness

Using Artificial Neural Network Methods for Modeling Moisture Susceptibility of Asphalt Mixture Modified by Nano TiO2

Using Artificial Neural Network Methods for Modeling Moisture Susceptibility of Asphalt Mixture Modified by Nano TiO2

Moisture susceptibility of asphalt mixtures: 2S2P1D rheological model approach and new index based on dynamic modulus master curve changes

A methodology is proposed for evaluating the induced moisture damage in asphalt mixtures via a new index called the dynamic modulus area ratio (DMAR), which is used to calculate the difference under the areas of the dynamic modulus master curves fitted by the 2S2P1D model before and after conditioning. Were evaluated 21 mixtures applied in the field by comparing data obtained via empirical tests, e.g., the tensile strength ratio and dynamic modulus ratio, using AASHTO T283. The behavior that moisture damage analysis based on stiffness loss measurements in modulus tests can lead to different conclusions than those based on damage resistance tests like TSR. The 2S2P1D model proved to be adequate to evaluate the changes promoted by the deleterious effect of water on the stiffness of the mixtures after the induced moisture damage cycle. For the DMAR, the results clearly differed according to the type of binder, indicating that the impact of water damage on the linear viscoelastic behavior depends on the type of binder used in the mixture. The estimation of susceptibility to moisture using the DMAR, which assesses broader temperature and frequency ranges, enables a stiffness evaluation that is closely related to the field impact on this property, making it possible to evaluate variations in the entire stiffness spectra of the mixtures; thus, it can be used in methods based on the performance for the selection of asphalt mixtures.

Evaluation of the adhesion property and moisture stability of rubber modified asphalt mixture incorporating waste steel slag

The present study was conducted to recycle waste tire rubber and steel slag (SS) in asphalt pavement and investigates the moisture stability of asphalt mixtures incorporating these solid wastes. To this end, two types of aggregates (SS and diabase), three kinds of SS content and multiple freeze–thaw cycles were considered and three kinds of adhesion assessment methods: pull-out test and surface free energy (SFE) method, and freeze–thaw splitting test were performed. Three corresponding adhesion evaluation indicators like adhesion strength, SFE characteristics, and tensile strength ratio were obtained and six energy parameters were introduced to characterize moisture susceptibility of asphalt mixture. To explore the relations between the SFE parameters and the adhesion evaluation indicators, a grey correlation analysis method was adopted. Asphalt mixtures with high consumption of SS obtained a better moisture resistance because SS has a superior adhesion strength and higher SFE components than diabase aggregate. Stripping energy increase was found to be the main failure mode of the asphalt rubber-SS aggregate system. SFE method provides a comprehensive and accurate evaluation of adhesion property of loose asphalt rubber–SS aggregate system and moisture stability of compacted asphalt mixtures.

Development of prediction models for moisture susceptibility of asphalt mixture containing combined SBR, waste CR and ASA using support vector regression and artificial neural network methods

Precise estimation of the moisture susceptibility of mixtures is a difficult approach because of the complicated characteristics of used materials under numerous environmental and traffic situations. As the virgin binder has low performance to different traffic and environmental conditions, utilization of additives are proposed. Current research discovers the possible utilization of artificial neural network (ANN) in forecasting the moisture susceptibility of asphalt mixtures modified by different additives. Over 100 samples were fabricated with three types of anti-stripping agents (named A, B, and C) with various contents (0.2%, 0.4%, and 0.6% by weight of binder), one percentage of CR (7% by weight of binder), one percentage of SBR (2% by weight of binder), and one type of AC-85/100 penetration grade bitumen, and tested through different tests such as; Texas boiling test, Tensile Strength Ratio (TSR), Fracture Energy Ratio (FER), and Resilient Modulus Ratio (RMR). Also, some physical and rheological properties of modified binders were investigated. The fracture energy (FE), indirect tensile strength (ITS) and resilient modulus (Mr) of mixtures improved by incorporation of CR and SBR. Also, have positive impact in enhancing the properties of mixtures. Based on results, ASA (B) has the best impact on enhancing the moisture susceptibility of mixtures. Moreover, some prediction models were proposed to compare with experimental methods. Support vector regression (SVR) and artificial neural network (ANN) models were designed for the prediction of TSR, RMR, and FER values. The results showed that ANN had better performance than SVR in all cases.

Using electromagnetic radiation for producing reclaimed asphalt pavement (RAP) Mixtures: Mechanical, induced heating, and sustainability assessments

This research investigates feasibility of using electromagnetic-based method to produce reclaimed asphalt pavement (RAP) mixtures. The conventional heating process in dryers of asphalt plants considerably over ages and diminishes mechanical properties of high RAP asphalt mixtures. In addition, the RAP asphalt plants (i.e., parallel flow, counter flow, and double barrel) have critical drawbacks in producing high RAP asphalt mixtures, such as partial activation of asphalt binder in RAP, non-uniform diffusion between virgin binder-rejuvenator-RAP binder, over aging of RAP aggregates, and high fossil fuels consumption, leading to mechanical, environmental, and economic consequences. Recently, the electromagnetic-based approaches (e.g., microwave radiation) were utilized in pavement industry for the diverse applications, including micro-crack healing and de-icing purposes. In this study, the capability of microwave for heating and preparing RAP mixture, containing different WEO amounts as rejuvenator, was investigated. The fracture properties at intermediate and low temperatures and moisture susceptibility of asphalt mixtures comprised of 80 and 100% RAP prepared using electromagnetic radiation were determined and compared against the mixtures made of traditional draft oven. Besides, effect of different WEO contents, as rejuvenator, were investigated. According to the results, heating of RAP aggregates using electromagnetic radiation as well as addition of WEO can remarkably enhance cracking resistance of asphalt mixtures. Moreover, the sustainability aspects of the suggested approach to prepare the RAP mixtures were compared against the conventional method considering energy consumption, equivalent CO2 emission, and cost values. The gray rational analysis (GRA) was conducted to rank the mixtures according to mechanical and sustainability aspects. The results reveal that utilization of electromagnetic radiation in producing high RAP asphalt mixtures can substantially improve sustainability aspects of RAP asphalt mixture.

Effect of rubber polymeric materials on moisture susceptibility of asphalt mixtures: Optimization and evaluation study

Pavements made with plain asphalt mixtures are subjected to premature failures due to the exposure to moisture. Polymers are one of the promising additives that are commonly used to extend the service life of asphalt mixtures. This paper evaluates the moisture sensitivity of asphalt mixtures using rubber polymeric materials such as crumb rubber and centrifuged latex. The crumb rubber material is collected from scrap tires (powder form), while the centrifuged latex material is extracted from hevea brasiliensis rubber tree (liquid form). Both crumb rubber and centrifuged latex polymeric materials are incorporated through the wet process at different percentages i.e., 2%, 4%, 6%, 8%, and 10% by the weight of the binder. The optimum crumb rubber and centrifuged latex contents are 8% and 6%, respectively, as per the storage stability test. Then moisture sensitivity of unmodified and rubber modified mixes is analyzed through different laboratory tests: marshal stability ratio, tensile strength ratio, and resilient modulus ratio. The tests clearly show that asphalt mixes exhibit higher moisture resistance with crumb rubber and centrifuged latex polymeric materials. In terms of marshal stability ratio and tensile strength ratio tests, crumb rubber material gives better moisture damage resistance than centrifuged latex material. The cost analysis reveals that rubber-modified mixes show slightly higher costs than unmodified mixes; however, this cost variation is insignificant. As a whole, pavements made with rubber-modified asphalt mixes have longer durability due to its higher moisture damage resistance.

Estimation of the surface free energy and moisture susceptibility of asphalt mastic and aggregate system containing salt storage additive

The moisture susceptibility of asphalt mixtures containing salt storage additive is a focus. The objective of this study was to characterize adhesion characteristic of asphalt-aggregate system containing salt storage additive. The contact angle test and boiling water test were carried out to obtain the contact characteristics and stripping behaviour of them. The results indicate that the contact angle values of asphalt mastic increased with the increment of salt storage additive resulting in poor wettability. And the surface free energy values of asphalt mastic slightly reduced with increased salt storage additive, and were remarkably less than that of water leading to bad affinity with stone under moisture condition. The adhesion works under moisture condition mainly depended on stone lithology, and had good negative correlation with the stripping area ratio values from boiling water test.