Determining of Asphalt Stiffness Modulus (original) (raw)
Related papers
A Research on Measurement of Stiffness of Asphalt Mixture at High Temperature
JOURNAL OF PAVEMENT ENGINEERING, JSCE, 2008
The stiffness of asphalt mixture is measured by indirect tensile test or unconfined compression test in generally. But, measurement in high temperature like 60°C is not generalized, and the test method used cutting core that diameter is about 50mm in real road is not established. In this study, it was tried that diameter and height of specimens were changed from 50 to100 mm and stiffness of the asphalt mixture from 5 to 60°C was measured by unconfined compression test. In a usual unconfined compression test, height of the specimen must be twice as long as diameter. But, from the result of this study, within strain is small enough in liner area of asphalt mixture, it was cleared that the stiffness of specimen that the length of height is equal to the diameter and the stiffness of specimen that height is twice as long as the diameter were almost equal. So, it was understood that the specimen that the lengths of height and diameter were 50mm was able to measure stiffness of asphalt mixture. It became possible to examine the core that was obtained in real road and measured steady in high temperature by this study. Stiffness at each temperature and loading time of dense graded asphalt mixture, porous asphalt mixture, SMA and mastic asphalt mixture were measured by established unconfined compression test. Results of this test corresponded to stiffness shown generally up to 40°C in Japan. In this study, the stiffness of each mixture in 60°C was able to be assumed.
Materials & Design, 2015
Stiffness of asphalt mixture is a fundamental design parameter of flexible pavement. According to literature, stiffness value is very susceptible to environmental and loading conditions. In this paper, effects of applied stress and temperature on the stiffness modulus of unmodified and Polyethylene Terephthalate (PET) modified asphalt mixtures were evaluated using Response Surface Methodology (RSM). A quadratic model was successfully fitted to the experimental data. Based on the results achieved in this study, the temperature variation had the highest impact on the mixture's stiffness. Besides, PET content and amount of stress showed to have almost the same effect on the stiffness of mixtures. The optimal amount of PET was found to be 0.41% by weight of aggregate particles to reach the highest stiffness value.
Arabian Journal for Science and Engineering, 2017
At present, Italian technical specifications only provide stiffness measurements in few cases, whereas they require the execution of the static indirect tensile strength test, both in mix design and in quality control phases. Despite this test is typically carried out only to determine the material strength, it is, however, possible to obtain a measure of the specimen stiffness properties from the stress-strain curve. The present paper deals with the correlation between asphalt concrete stiffness measurements obtained through dynamic indirect tensile tests, according to EN 12697-26, and static indirect tensile strength tests, according to EN 12697-23. In particular, data from static tests have been processed to obtain stiffness measurements through the application of Hondros' theory or graphically from the stress-strain curve. Although based on empirical derivation, this relationship would enable the laboratories that are not equipped with a proper machine for dynamic modulus tests to estimate the stiffness properties of the bituminous material, by exclusively performing simple static tests. The experimental program included static and dynamic indirect tensile tests at 10, 20 and 30 • C on three asphalt concretes, different for binder type and compacted to two air voids contents. Results proved that good correlations (R 2 values higher than 0.92) can be established between dynamic modulus and static moduli, independently from test conditions and mixture composition.
Anisotropy in compressive strength and elastic stiffness of normal and polymer-modified asphalts
Soils and Foundations, 2014
Anisotropy in the compressive strength and the elastic stiffness of normal hot-mix asphalt (HMA) and polymer-modified asphalt (PMA) were investigated experimentally. Two types of prismatic specimen with planes of compaction either normal to or parallel to the applied axial compression were used. Both axial and lateral principal strains were measured locally. Continuous monotonic loadings at a constant strain rate were axially applied to investigate the anisotropy in the compressive strength. Very small strain-amplitude cyclic stresses were also applied by means of another load-controlled apparatus to investigate the anisotropy in the elastic stiffness. The followings were found: (i) compressive strengths of both HMA and PMA are anisotropic in that the values for the vertical direction were significantly larger than those of horizontal direction; (ii) the small strain stiffness of both HMA and PMA are anisotropic with the vertical elastic Young's modulus being greater than the horizontal elastic Young's modulus; (iii) the elastic Young's modulus is stress level dependent, exhibiting a hypo-elastic behaviour; and (iv) the elastic Young's modulus becomes greater with the applications of the normal and the polymer-modified asphalt cement binders.
An Easy Way To Determine The Flexural Quality Of Asphalt Is Using ASTM D113 – 07 and SNI 2432:2011
Civilla : Jurnal Teknik Sipil Universitas Islam Lamongan, 2022
Asphalt is a material that has non-volatile properties and softens gradually when heated and functions as a binder for aggregates and as a surface covering material to make it impermeable to water. However, asphalt also has a weakness. Namely, it is easy to crack and be damaged when vehicles pass through the main road. To overcome cracked and worn roads, it is necessary to test the ductility of asphalt so that the road becomes flexible/plastic. This ductility test is very important because it greatly affects the pavement layer; Therefore, a ductility test is needed to determine the level of plasticity of an asphalt. The asphalt ductility test method refers to the specifications of ASTM D113 – 07 and SNI 2432:2011 with 3 samples of test objects and a test instrument called a ductilometer of type TAS – 250. Based on the ductility test, the asphalt ductility reaches an average elongation of 117.33 cm; This value indicates that the plasticity level of the asphalt has met the specificati...
Contract, 2005
The proposed Mechanistic-Empirical Pavement Design Guide (MEPDG) procedure is an improved methodology for pavement design and evaluation of paving materials. Since this new procedure depends heavily on the characterization of the fundamental engineering properties of paving materials, a thorough material characterization of mixes used in Virginia is needed to use the MEPDG to design new and rehabilitated flexible pavements. The primary objective of this project was to perform a full hot-mix asphalt (HMA) characterization in accordance with the procedure established by the proposed MEPDG to support its implementation in Virginia. This objective was achieved by testing a sample of surface, intermediate, and base mixes. The project examined the dynamic modulus, the main HMA material property required by the MEPDG, as well as creep compliance and tensile strength, which are needed to predict thermal cracking. In addition, resilient modulus tests, which are not required by the MEPDG, were also performed on the different mixes to investigate possible correlations between this test and the dynamic modulus. Loose samples for 11 mixes (4 base, 4 intermediate, and 3 surface mixes) were collected from different plants across Virginia. Representative samples underwent testing for maximum theoretical specific gravity, asphalt content using the ignition oven method, and gradation of the reclaimed aggregate. Specimens for the various tests were then prepared using the Superpave gyratory compactor with a target voids in total mix (VTM) of 7% ± 1% (after coring and/or cutting). The investigation confirmed that the dynamic modulus test is an effective test for determining the mechanical behavior of HMA at different temperatures and loading frequencies. The test results showed that the dynamic modulus is sensitive to the mix constituents (aggregate type, asphalt content, percentage of recycled asphalt pavement, etc.) and that even mixes of the same type (SM-9.5A, IM-19.0A, and BM-25.0) had different measured dynamic modulus values because they had different constituents. The level 2 dynamic modulus prediction equation reasonably estimated the measured dynamic modulus; however, it did not capture some of the differences between the mixes captured by the measured data. Unfortunately, the indirect tension strength and creep tests needed for the low-temperature cracking model did not produce very repeatable results; this could be due to the type of extensometers used for the test. Based on the results of the investigation, it is recommended that the Virginia Department of Transportation use level 1 input data to characterize the dynamic modulus of the HMA for projects of significant impact. The dynamic modulus test is easy to perform and gives a full characterization of the asphalt mixture. Level 2 data (based on the default prediction equation) could be used for smaller projects pending further investigation of the revised prediction equation incorporated in the new MEPDG software/guide. In addition, a sensitivity analysis is recommended to quantify the effect of changing the dynamic modulus on the asphalt pavement design. Since low-temperature cracking is not a widespread problem in Virginia, use of level 2 or 3 indirect tensile creep and strength data is recommended at this stage.
2010
The use of foamed cold-mix asphalt (FCMA) can potentially saves energy and fuel consumption and reduces greenhouse gas emission. For these reasons, FCMA has been gaining popularity worldwide. These benefits can be realized because foamed bitumen enables the coating of aggregate particles at ambient temperature. It should be understood that in FCMA not all aggregate particles are coated by binder. The sprayed foamed bitumen is seen distributing on the fine particles only and hence its physical performance is unlike the conventional asphalt. In order to gain better understanding about these unique characteristics, an investigation to the fundamental properties of FCMA is warranted. This paper presents the results from a stiffness investigation of FCMA in laboratory by using ITSM (Indirect Tensile Stiffness Modulus) test. The results show that the ITSM test is suitable to evaluate the stiffness characteristics of FCMA materials. It was found that mixing quality is an important aspect i...
Experimental Investigation of Strength and Stiffness Characteristics of Hot Mix Asphalt (HMA)
Procedia Engineering, 2014
Rutting is a common phenomenon on pavements in Pakistan. Resilient modulus is one the important properties used in the mechanistic analysis of pavement response under dynamic traffic loads as well as used to study the rutting behavior of pavement. This research study investigates the effect of specimen diameter, bitumen grade and compactive effort on the resilient modulus (stiffness) and Indirect tensile strength (Strength) of asphalt concrete. The analysis of experimental results revealed that both the strength and stiffness values for Polymer Modified Bitumen grade were greater than that of unmodified penetration grade bitumen. Similarly, the resilient modulus and indirect tensile strength values of specimens prepared with 100 mm diameter and compacted with Marshall Hammer were more than that of specimens prepared with 150 mm diameter and compacted with gyratory compactor. This research will help the highway agencies in modifying their design methods for asphalt concrete pavements.
An Experimental-Based Approach to Predict Asphalt Mixtures Permanent Deformation Behavior
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
Present study illustrates the utilization of horizontal shift factors obtained from the dynamic modulus test to predict laboratory-based asphalt mixture permanent deformation characteristics using a uniaxial repeated load permanent deformation test (URLPD). The research methodology is based on an assumption that the asphalt mixtures are considered as thermorheologically simple beyond the linear viscoelastic region. Therefore, shift factors obtained from a dynamic modulus test can be used for the development of master curves using URLPD test. Twelve asphalt mixtures comprising of three asphalt binders of different performance grade, four aggregate gradations (gap and dense graded) were tested. Wheel tracker test was conducted for a relative comparison of different asphalt mixtures’ rut resistance. Time and temperature superposition principle has been used for the estimation of permanent deformation at a reference temperature. Horizontal shift factors obtained from the dynamic modulus...