scholarly journals Investigating the Effect of Hydrophobic Additives in Moisture Damage Reduction of Asphalt Mixtures

Author(s):  
Gholam Hossein Hamedi ◽  
Amir Shabani ◽  
Yasaman Safargar

In order to increase the life of the asphalt mixture and reduce the cost of the pavement life cycle, methods must be provided to improve the quality. Accordingly, the effects of aggregate surface coating with hydrophobic material in order to modify the aggregate mixture’s polar properties and reduce its hydrophilic properties are investigated. To this end, limestone and granite aggregates, 60-70 bitumen, and Two types of additives were used as the primary materials for the construction of asphalt mixtures. Thermodynamic concepts with cyclic loading have been used to evaluate the effects of these additives. The results obtained in this study indicate that the hydrophobic coating on the aggregate surface has increased the acidic components and decreased the alkaline components of the surface free energy for both types of aggregates. These changes will increase the bitumen-aggregate adhesion and make a better coating of bitumen on the aggregate surface. The results based on thermodynamic concepts suggest that the aggregate surface coating has reduced the system’s separation energy and the desire for stripping. The results of the dynamic modulus in wet to dry conditions also approve this outcome. The combination of thermodynamic concepts and the cyclic loading results show that the coating on the aggregate surface has reduced the aggregate’s stripping from bitumen. It is also obvious that the samples made with granite aggregates, which have acidic properties, are prone to moisture damage and have a higher tendency to strip.

2012 ◽  
Vol 509 ◽  
pp. 209-214
Author(s):  
Shao Peng Wu ◽  
Pan Pan ◽  
Ming Yu Chen

With the widespread application of asphalt mixture, current demand from transportation managers for construction and maintenance of their pavement network consumes large numbers of aggregates. If agencies excessively favor to some certain kinds of excellent aggregates, the cost of construction could be considerably expensive. The major objective of this study is to determine the feasibility of utilizing dacite in asphalt mixtures. By means of Marshall, freeze-thaw, rutting and three-point bending tests, the performances of dacite and basalt asphalt mixture are compared. The results of the testing illustrate that dacite asphalt mixture is more susceptible to gradation and asphalt content than basalt asphalt mixture. Meanwhile it is showed that the performances of dacite asphalt mixture can be improved greatly with the involvement of additives including active mineral powder and cement. Furthermore, it is validated that dacite can be used as alternative aggregate in asphalt mixture.


Author(s):  
Moses Akentuna ◽  
Louay N. Mohammad ◽  
Sanchit Sachdeva ◽  
Samuel B. Cooper ◽  
Samuel B. Cooper

Moisture damage of asphalt mixtures is a major distress affecting the durability of asphalt pavements. The loaded wheel tracking (LWT) test is gaining popularity in determining moisture damage because of its ability to relate laboratory performance to field performance. However, the accuracy of LWT’s “pass/fail” criteria for screening mixtures is limited. The objective of this study was to evaluate the capability of the LWT test to identify moisture susceptibility of asphalt mixtures with different moisture conditioning protocols. Seven 12.5 mm asphalt mixtures with two asphalt binder types (unmodified PG 67-22 and modified PG 70-22), and three aggregate types (limestone, crushed gravel, and a semi-crushed gravel) were utilized. Asphalt binder and mixture samples were subjected to five conditioning levels, namely, a control; single freeze–thaw-; triple freeze–thaw-; MiST 3500 cycles; and MiST 7000 cycles. Frequency sweep at multiple temperatures and frequencies, and multiple stress creep recovery tests were performed to evaluate asphalt binders. LWT test was used to evaluate the asphalt mixture samples. Freeze–thaw and MiST conditioning resulted in an increase in stiffness in the asphalt binders as compared with the control. Further, freeze–thaw and MiST conditioning resulted in an increase in rut depth compared with the control asphalt mixture. The conditioning protocols evaluated were effective in exposing moisture-sensitive mixtures, which initially showed compliance with Louisiana asphalt mixture design specifications.


Author(s):  
Félix Pérez-Jiménez ◽  
Ramon Botella ◽  
Rodrigo Miró

Fatigue cracking is considered one of the main damage mechanisms in asphalt pavement design. Design methods use fatigue laws obtained by laboratory testing of the materials involved. Typically, these tests consist of subjecting the asphalt mixture to cyclic loading until failure occurs. However, failure is associated not with specimen fracture (which is unusual), but with a slight decrease in the mechanical properties of the material, usually in the complex modulus. As a consequence, it is important to differentiate between real damage to the material and changes in its viscoelastic behavior and thixotropy. It is also crucial to account for the healing that occurs in asphalt material after rest periods. The above considerations are important in the fatigue testing of asphalt binders because these materials show pronounced viscoelastic behavior and thixotropy, especially when subjected to cyclic loading. This paper demonstrates that in many cases what is taken for fatigue failure during testing (i.e., a decrease in the complex modulus below half of its initial value) is actually thixotropy. Thus, the complex modulus can be recovered by reducing the loading or, as in this study, the strain applied. In contrast, asphalt mixtures experience irreversible damage, and depending on the asphalt binder, the thixotropic effects are more or less pronounced. This paper analyzes the failure criteria currently used in the fatigue testing of asphalt mixtures and binders and evaluates the parameters chosen, namely, complex modulus (G*) and phase angle (δ) to characterize asphalt binders (G*sin δ). A cyclic uniaxial tension–compression test under strain-controlled conditions was performed. Three test modalities were used: time sweeps (constant strain amplitude until total failure), increasing strain sweeps (increase in strain amplitude every 5,000 cycles), and up-and-down strain sweeps (alternating increases and decreases in strain amplitude).


2019 ◽  
Vol 8 (3) ◽  
pp. 6146-6149

It is desirable to incorporate Reclaimed Asphalt Pavement into the asphalt mixtures, which provides several benefits i.e. economic, environmental and performance. It is necessary to study, the economic analysis of the RAP since that incur several contingencies to the asphalt mixtures. In this study, a simple approach is used to evaluate the production cost of the asphalt and RAP incorporated asphalt mixtures. Apart from that Waste Vegetable Oil (WVO) is used as a rejuvenator to enhance the properties of the mixture. In this study, asphalt mixture production cost is evaluated and cost of each material is taken from the Public Works Department Standard Scheduled of Rates (PWD – SSR) and the market survey techniques are followed. From the cost-benefit ratio, it is observed that the reduction in the Optimum Binder Content (OBC) provides great economic savings to the production cost. The incorporation of the RAP reduced the asphalt content and reduced the production cost of the asphalt mixtures. The addition of the WVO further reduced the OBC but increased the production cost compared to the non-rejuvenated mixture. The increase in the production cost is due to the extra cost invested on the WVO and other contingencies.


2020 ◽  
Vol 5 (2) ◽  
pp. 20 ◽  
Author(s):  
Hilde Soenen ◽  
Stefan Vansteenkiste ◽  
Patricia Kara De Maeijer

Moisture susceptibility is still one of the primary causes of distress in flexible pavements, reducing the pavements’ durability. A very large number of tests are available to evaluate the susceptibility of a binder aggregate combination. Tests can be conducted on the asphalt mixture, either in a loose or compacted form, or on the individual components of an asphalt pavement. Apart from various mechanisms and models, fundamental concepts have been proposed to calculate the thermodynamic tendency of a binder aggregate combination to adhere and/or debond under wet conditions. The aim of this review is to summarize literature findings and conclusions, regarding these concepts as carried out in the CEDR project FunDBits. The applied test methods, the obtained results, and the validation or predictability of these fundamental approaches are discussed.


2019 ◽  
Vol 11 (0) ◽  
pp. 1-6
Author(s):  
Lina Šneideraitienė ◽  
Daiva Žilionienė

The European building sector is facing a pressing issue of natural resources. Importing road building materials for the asphalt surfacing increases the cost of the asphalt mixture. The asphalt surfacing mixtures shall consist of a mixture of graded aggregates accounting for 80−90% of the total volume of the asphalt mixture, or 90−96% of the total weight of the asphalt mixture and binder: road bitumen or polymer modified bitumen. In the Republic of Lithuania, asphalt mixes are designed in accordance to the Design Regulations for Road Pavement Standardized Pavement Structures KP SDK 19 and accordance to the normative documents and their requirements for graded aggregates and binders. Road builders import graded aggregates to asphalt mixes from other countries, and this increases the cost of asphalt mixes. According to the scientific researches in the Lithuanian quarry Petrašiūnai II, using unique production technology is produced class I dolomite crushed stone, which mechanical, physical properties and designed asphalt mixtures can replace imported graded aggregates. The economic question remains as to the economic effect of the most commonly used asphalt mixtures in Lithuania AC 11 VS (asphalt mixture of asphalt pavement wearing course) and SMA 11 S (crushed and mastic asphalt) made from indigenous minerals compared to imported minerals. The aim of the paper is to perform the calculation and evaluation of the economic effect of asphalt mixtures AC 11 VS, SMA 11 S with different minerals and micro-aggregate. The paper identifies and analyses the properties of asphalt test mixtures, and identifies the locations of mineral suppliers in Lithuania. According to the economic impact assessment scheme, the economic effect of asphalt mixtures AC 11 VS, SMA 11 S with different minerals and micro-aggregate was calculated. According to the calculations made, the economic effect of producing asphalt mixtures AC 11 VS, SMA 11 S with class I dolomite chips is 13−14%.


2018 ◽  
Vol 30 (10) ◽  
pp. 04018238 ◽  
Author(s):  
Fereidoon Moghadas Nejad ◽  
Mohyedin Asadi ◽  
Gholam Hossein Hamedi ◽  
Mohamad Reza Esmaeeli

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Dae-Wook Park ◽  
Tam Minh Phan ◽  
Yeong-Min Kim

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.


2015 ◽  
Vol 73 (4) ◽  
Author(s):  
Meor Othman Hamzah ◽  
Muhammad Rafiq Kakar ◽  
Mohd Rosli Hainin

This paper presents a short review on moisture induced damage in asphalt mixtures. Moisture induced damage is one of the most common causes of pavement distress that results in loss of strength, stripping, raveling, fatigue damage and permanent deformation. Different mechanisms have been used to explain the process of moisture damage in asphalt pavements. However, the moisture damage mechanism takes place due to the interaction of several different processes. The applicability of a single test method to evaluate moisture damage is impractical to a wide range of materials and conditions. Therefore, a new laboratory based testing procedure and analysis protocol is required, with the aim to simultaneously consider the effects of both traffic impact and moisture damage. The proper material design, efficient construction methods, reliable laboratory techniques and well planned highway surface and subsurface drainage systems may lead towards a sustainable asphalt pavement that is sufficiently durable to resist moisture damage. Although considerable advances concerning the subject have been reported, yet there is still a need to address certain issues that are actually involved in the process of asphalt mixture moisture susceptibility.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7151
Author(s):  
Xinyu Hu ◽  
Xiaowei Wang ◽  
Nanxiang Zheng ◽  
Qiang Li ◽  
Jinyue Shi

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.


Sign in / Sign up

Export Citation Format

Share Document