scholarly journals The Effects of Nano Bentonite and Fatty Arbocel on Improving the Behavior of Warm Mixture Asphalt against Moisture Damage and Rutting

2020 ◽  
Vol 6 (5) ◽  
pp. 877-888
Author(s):  
Sepehr Saedi ◽  
Seref Oruc
Keyword(s):  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Maintenance Cost ◽  
Permanent Displacement ◽  
Moisture Sensitivity ◽  
Asphalt Cement ◽  
Dynamic Creep ◽  
Indirect Tensile ◽  
Reduce Energy Consumption ◽  
Low Performance

The use of warm mix asphalt (WMA) technology has increased dramatically in recent years to protect the environment and reduce energy consumption. Despite numerous advantages, WMAs are less commonly used as a result of their lower performance in comparison to HMAs. One of the main reasons for the low performance of WMAs is their high moisture sensitivity. In recent decades, bitumen modifiers have been used to improve the performance of asphalt mixtures. One of the additives that has recently been used to modify the characteristics of bitumen, is bentonite. The grade of asphalt cement used in this study is PG 64 -22 and the Bitumen is modified with 1, 3, 5 and 7% nano bentonite. Also, 0.3% fatty Arbocel has been used for the preparation of WMA. Indirect tensile strength (ITS) test and Nicholson stripping test are used to determine moisture sensitivity and dynamic creep test and LCPC are also used to evaluate the rutting potential. The results indicate that, increasing the percentage of nano bentonite and applying 0.3% of fatty Arbocel improves the resistance of mixture against moisture damage. Also it was found that increasing the mixture hardness decreases the permanent displacement and rutting potential of WMAs. So, it is suggested that the consumption of these additives increases WMA’s lifetime and decreases its maintenance cost.

scholarly journals Experimental Investigation of Moisture Sensitivity and Damage Evolution of Porous Asphalt Mixtures

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7151
Author(s):  
Xinyu Hu ◽  
Xiaowei Wang ◽  
Nanxiang Zheng ◽  
Qiang Li ◽  
Jinyue Shi
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Damage Evolution ◽  
Moisture Damage ◽  
Exponential Model ◽  
Asphalt Mixtures ◽  
Moisture Sensitivity ◽  
Porous Asphalt ◽  
Dry Conditions ◽  
Indirect Tensile

Porous asphalt (PA) mixtures are designed with a high air void (AV) (i.e., 18~22%) content allowing rainwater to infiltrate into their internal structures. Therefore, PA mixtures are more sensitive to moisture damage than traditional densely graded asphalt mixtures. However, the moisture damage evolution of PA mixtures is still unclear. The objective of this study was to investigate the moisture damage evolution and durability damage evolution of PA mixtures. The indirect tensile test (ITT), ITT fatigue test, and Cantabro loss test were used to evaluate the moisture sensitivity and durability of PA mixtures, and a staged ITT fatigue test was developed to investigate the damage evolutions under dry and wet conditions. Indirect tensile strength (ITS), fatigue life, indirect tensile resilience modulus (E), and durability decreased with the increment of moisture damage and loading cycles. The fatigue life is more sensitive to the moisture damage. The largest decrements in ITS and E were found in the first 3000 loading cycles, and PA mixtures tended to fail when the decrement exceeded 60%. Damage factors based on the ITS and E are proposed to predict the loading history of PA mixtures. The durability damage evolution and damage factors could fit an exponential model under dry conditions. Moisture had a significant influence and an acceleration function on the moisture damage evolution and durability damage evolution of PA mixtures.

scholarly journals Examining the Effect of Dry Resin on Moisture Sensitivity of Asphaltic Mixtures

2018 ◽  
Vol 4 (7) ◽  
pp. 1714 ◽  
Author(s):  
Morteza Ghaffari Jajin ◽  
G. Hosein Hamedi
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Hydrated Lime ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Polymer Additive ◽  
Moisture Sensitivity ◽  
Indirect Tensile ◽  
Effect Of Moisture ◽  
Moisture Resistant

Moisture damage in asphaltic mixtures is defined by the loss of durability and resistance caused by the effect of moisture. The most common way to improve moisture damage in asphaltic mixtures is to use anti-strip additives. This study tended to use dry resin polymer additive to make a moisture-resistant asphaltic mixture. Two types of aggregate indicating different sensitivities against moisture were studied. In order to compare the effect of this material with other anti-strip additives, this study evaluated the effect of hydrated lime on reducing moisture damage and comparing its effect with dry resin polymer additive. The effect of these materials was evaluated by mechanical and thermodynamic concepts using indirect tensile ratio and surface free energy. The results indicated that dry resin polymer used in this study increased alkaline content and reduced acidic content of bituminous surface free energy, resulting in more adhesion between acidic aggregates which are more sensitive to resistance. It also improved bitumen-aggregate adhesion and reduced strip rate. Moreover, hydrated lime as an aggregate anti-strip agent and dry resin polymer as a bituminous modifier significantly increased the resistance of warm asphalt mixtures against moisture. The results of this study show that dry resin polymer can be used as an anti-strip agent instead of hydrated lime with operational problems.

Moisture Sensitivity of Bituminous Mixtures with Compound Fly Ash Modifier

2012 ◽  
Vol 509 ◽  
pp. 149-154
Author(s):  
Jun Xie ◽  
Jun Cai ◽  
Shao Peng Wu ◽  
Ling Pang
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Fly Ash ◽  
Moisture Damage ◽  
Moisture Sensitivity ◽  
Bituminous Mixtures ◽  
Primary Object ◽  
New Type ◽  
Indirect Tensile ◽  
Short Span

Bitumen pavement suffers from moisture damage mainly due to loss of durability and stability in a short span of service life. Filler is known to be capable of increasing the stiffness of bitumen binder, contributing to improvement of moisture sensitivity of bitumen mixture. In this paper a new type of filler named 'Compound Fly Ash Modifier' (CFAM) was introduced in order to enhance the bond strength between acidic aggregate with bitumen. The primary object is to determine the effect of CFAM on the moisture sensitivity of bitumen mixtures prepared by gneiss and granite respectively, which are termed acidic aggregate. Modified Lottman test and fatigue test were conducted. The results show that CFAM improves the resistance of mixes to moisture damage in the increase in indirect tensile strength and the extension of fatigue life. Finally the mechanism of modified effects for CFAM is discussed.

Effect of Modified Asphalt Cement of the Performance of Stone Matrix Mixtures

2020 ◽  
Vol 38 (5A) ◽  
pp. 789-800
Author(s):  
Duaa A. Khalaf ◽  
Zaynab I. Qasim ◽  
Karim H. Al Helo
Keyword(s):  
Tensile Strength ◽  
Fracture Resistance ◽  
Laboratory Tests ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Asphalt Cement ◽  
Indirect Tensile ◽  
Marshall Stability ◽  
Stone Matrix

This research investigates the behavior of Stone Matrix Asphalt mixtures (SMA) modified with styrene-butadiene-styrene (SBS) polymer at four percentages (1, 2, 3 and 4%) by weight of asphalt cement. The moisture susceptibility and rutting were taken into consideration in this study. To achieve the objective of this research the superpave system is conducted to design the asphalt mixtures. The physical properties of aggregate, bitumen and other mix materials were assessed and evaluated with the laboratory tests. The mixtures were prepared using penetration Graded (40-50) bitumen and a chemical named Polypropylene Fibers was used as a stabilizing additive. Fibers have been used in SMA mixtures for two main reasons: To increase the toughness and fracture resistance of hot mix asphalt (HMA) and to act as a stabilizer to prevent drain down of the asphalt binder. The laboratory tests include indirect tensile strength test, Marshall stability and retained Marshall Stability test (RMS). For rutting test the Roller wheel compactor is used for preparing the asphaltic samples and Wheel tracking device is used to evaluate the rutting of asphaltic slabs. The results showed that the SBS polymer asphalt mixture gave better moisture sensitivity and better fracture resistance according to the study.It is noted that indirect tensile strength ratio (TSR) increases by 93.1 % and the rut depth decreases by 32.5 % when adding 3% SBS polymer to SMA.

scholarly journals Investigating the Effect of Metal Nanomaterials on the Moisture Sensitivity Process of Asphalt Mixes

2020 ◽  
Author(s):  
Iraj Bargegol ◽  
Farhad Sakanlou ◽  
Mohsen Sohrabi ◽  
Gholam Hossein Hamedi
Keyword(s):  
Free Energy ◽  
Cyclic Loading ◽  
Resilient Modulus ◽  
Moisture Damage ◽  
Mechanical Tests ◽  
Destructive Effect ◽  
Moisture Sensitivity ◽  
Asphalt Mixes ◽  
Indirect Tensile ◽  
Sensitivity Indicator

One of the most common damages in asphalt mixes is the destructive effect of moisture on the binder cohesion and binder–aggregate adhesion which is called moisture damage. There are various methods to improve adhesion and reduce moisture damage in asphalt mixes. The most common of them is using an appropriate additive for binder modification. Accordingly, the current research was conducted to investigate the effect of two nanomaterials (Nano CuO, and Nano SnO2) in 2 different percentages on 2 types of aggregates (granite and limestone) and a type of base binder. In order to investigate the effect of nanomaterials, indirect tensile cyclic loading (the same as resilient modulus test) in dry and wet conditions and surface free energy (SFE) method were used. The moisture sensitivity indicator which shows stripping percentage of aggregate surface in loading cycles using SFE results and indirect tensile cyclic loading, has been considered as the moisture sensitivity indicator in this research. Results of mechanical tests used in this research show that nanomaterials have significantly increased asphalt mixes strength in comparison to control specimens. Results obtained from SFE method show that nanomaterials increase the cohesion free energy; this change causes a reduction in the possibility of failure in binder membrane. Additionally, nanoparticles have increased and reduced basic component and acidic component of SFE, respectively. This leads to improvement of their adhesion with acidic aggregates, which is sensitive to moisture damage.

Effects of Dosage of Warm Mix Asphalt Additive on Stiffness, Cracking Susceptibility, and Moisture Sensitivity Characteristics

2020 ◽  
Author(s):  
Salvatory John Materu ◽  
Ahmed Shalaby ◽  
A. Ghazy
Keyword(s):  
Laboratory Testing ◽  
Asphalt Pavement ◽  
Moisture Damage ◽  
Warm Mix Asphalt ◽  
Strength Ratio ◽  
Chemical Additives ◽  
Moisture Sensitivity ◽  
Asphalt Cement ◽  
Overall Performance ◽  
The Common

Warm Mix Asphalt (WMA) technology has the capability of lowering asphalt mixing and compacting temperature by 30°C or more without compromising the performance of asphalt pavement. This results to a lower cooling rate that allows for long haul, and sufficient compaction time. The objective of this study is to evaluate the effectiveness of the common chemical additives on the properties of WMA mixtures through field and laboratory testing programs. Three dosages (0.3, 0.5 and 0.7 percent by weight of asphalt cement) were used without changing the job mix formula. Among the different additive dosage used, 0.5% had a better overall performance. For example, the moisture sensitivity test for the 0.5% WMA indicated the highest Tensile Strength Ratio (TSR); subsequently, low moisture damage. All WMA mixtures had low rutting resistance potential and higher cracking resistance compared to conventional mix.

Laboratory Investigation on the Effects of Flaky Aggregates on Dynamic Creep and Resilient Modulus of Asphalt Mixtures

2014 ◽  
Vol 70 (4) ◽  
Author(s):  
Mohd Zul Hanif Mahmud ◽  
Haryati Yaacob ◽  
Ramadhansyah Putra Jaya ◽  
Norhidayah Abdul Hassan
Keyword(s):  
Laboratory Tests ◽  
Significant Contribution ◽  
Resilient Modulus ◽  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Tensile Modulus ◽  
Asphalt Mixtures ◽  
Dynamic Creep ◽  
Bitumen Content ◽  
Indirect Tensile

This paper presents an investigation on the effects of flaky aggregates in asphalt mixture. In general, aggregate characteristics are critical to the performance of asphalt mixture. Therefore, flaky aggregate is normally avoided simply because it has significant contribution towards the gradation and reduces the interlocking characteristics of aggregates within asphalt mixture. In practice, it is recommended that the amount of flakiness aggregate should be limited to 25% or less. This study evaluates the mechanical properties of asphalt mixture specimens prepared with various percentages of flaky aggregates particularly 10%, 20% and 30% by the total weight of the mixture. Several laboratory tests were conducted including Marshall properties test, Indirect Tensile Modulus test and Dynamic Creep test. The results show that higher bitumen content is required with the increased in the amount of flaky aggregates added to mixture. Furthermore, greater amount of flaky aggregates tends to reduce the mixture’s resilient modulus and its resistance against permanent deformation.

A Comparative Study of Anti-Stripping Additives in Porous Asphalt Mixtures

2014 ◽  
Vol 70 (7) ◽  
Author(s):  
Mohamad Yusri Aman ◽  
Zulkurnain Shahadan ◽  
Mohd Zaime Mat Noh
Keyword(s):  
Asphalt Mixtures ◽  
Cohesive Failure ◽  
Moisture Sensitivity ◽  
Asphalt Mixes ◽  
Air Voids ◽  
Porous Asphalt ◽  
Coefficient Of Permeability ◽  
Indirect Tensile ◽  
Aashto T283 ◽  
Quarry Dust

Presence of water in porous asphalt mixtures detrimentally affected the bonding between binder-aggregate interface and cohesive failure within the binder-filler mastic, making them prone to stripping which contribute to the performance and durability. This paper presents the effect of anti-stripping additives in porous asphalt mixes. In this study, the Marshall specimens were prepared using quarry dust, ordinary Portland Cement (OPC) and Pavement Modifier (PMD) as filler then mixed with 60/70 penetration grade bitumen. The specimens were measured for air voids content and coefficient of permeability and subsequently tested using indirect tensile and Cantabro tests. The moisture sensitivity of porous asphalt was determined based on the ratio of dry and conditioned specimens according to AASHTO T283. The specimens prepared with PMD showed lower air voids content, hence decrease the permeability to give a higher tensile strength and lower abrasion loss compared to specimens prepared with OPC and quarry dust. Based on the results, the PMD filler has a great potential to improve resistance to moisture damage compared to mixes with OPC and specimens prepared with quarry dust fillers.

scholarly journals Influence of Antistripping Additives and Rejuvenators on Healing Performance of Moisture-Damaged HMA

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Dae-Wook Park ◽  
Tam Minh Phan ◽  
Yeong-Min Kim
Keyword(s):  
Asphalt Mixture ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Moisture Resistance ◽  
Three Point Bending ◽  
Indirect Tensile ◽  
Damage Healing ◽  
Aged Binder

This study aims to evaluate the effect of different rejuvenators and antistripping agents on the healing performance of hot mix asphalt (HMA). Two damage HMA series (e.g., moisture damage and aged damage) were subjected to either induction or microwave heating. A PG64-22 virgin and aged binder were used and modified with several additives. Three long-term aged binders (e.g., PAV5, PAV15, and PAV20) were conducted by pressure aging vessel (PAV) test. The moisture damage series fabricating with a new binder was further categorized into four different freeze-thaw (FT) cycles (e.g., 0FT, 1FT, 3FT, and 5FT). Also, the aged series was fabricated with three different aged binders. A total of eight damage-healing cycles were applied to all asphalt mixtures, examined by the three-point bending test. The moisture resistance of modified asphalt mixture was examined by indirect tensile strength test. Overall, asphalt mixtures modified with either antistripping additives or rejuvenators not only obtained higher moisture resistance but also gained better healing performance under moisture damage. In addition, the study showed a probable correlation between moisture damage and long-term aging in terms of healing performance, such as PAV15 and 3FT cycles and PAV20 and 5FT cycles.

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