Effects of Testing Time and Confining Pressure on Falling-Head Permeability Tests of Hot-Mix Asphalt Concrete

2000 ◽  
Vol 1723 (1) ◽  
pp. 92-96 ◽  
Author(s):  
Kevin D. Hall ◽  
Josue Cruz ◽  
Hooi Ng
Keyword(s):  
Asphalt Concrete ◽  
Hot Mix Asphalt ◽  
Confining Pressure ◽  
Water Infiltration ◽  
Time Interval ◽  
Testing Time ◽  
Test Results ◽  
Testing Procedures ◽  
Superpave Gyratory Compactor ◽  
Flexible Wall

Superpave implementation has resulted in increased interest in the permeability of hot-mix asphalt concrete. Relatively open-graded Superpave mixes have given rise to concern about premature pavement failures due to increased water infiltration from the surface. Arkansas is investigating the use of a falling-head permeability test to evaluate Superpave mixes with respect to potential performance problems caused by increased permeability. The initial phase of the project concerns the development of laboratory testing procedures and equipment. Superpave field mixes from projects in Arkansas were sampled to investigate permeability testing parameters. In addition, compacted test specimens from a round-robin study of permeability were included in the testing matrix. For the Arkansas mixes, loose mix sampled at the hot-mix plant was compacted using the Superpave gyratory compactor. Field cores were also taken from completed pavement sections. Permeability tests were conducted on all samples to investigate the effect of testing time (15, 30, 45, and 60 min) and confining pressure (69 and 96.5 kPa) on the measured permeability values. Results of the testing suggest that neither the time interval used in measuring the head drop in a falling-head test nor the confining pressure used in the flexible wall testing apparatus significantly affects test results. These findings will greatly simplify testing methods and setup, making the test more attractive as a relatively routine tool for the mix design laboratory.

scholarly journals Evaluating Marination Effect of Diluted Zycothermon Hot Mix Asphalt

2017 ◽  
Vol 3 (3) ◽  
pp. 18
Author(s):  
Ilham I. Mohammed
Keyword(s):  
Tensile Strength ◽  
Asphalt Concrete ◽  
Hot Mix Asphalt ◽  
Asphalt Mixture ◽  
Strength Test ◽  
Stability Test ◽  
Test Results ◽  
Great Range ◽  
Tensile Strength Test ◽  
Moisture Conditions

Sinceasphalt concrete undergo different failure problems at different temperature and moisture conditions and for years many scientists and researchers used different kinds of materials and variety of methods for improving the properties of asphalt concrete made with either basalt or limestone.So it became necessary to provide the best possible way to get rid of these failure problems.In this study diluted zycotherm nanomaterial at three different percentages by weight of aggregate used with two aggregate types, basalt and limestone, and asphalt concrete made with the marinated aggregate and later the properties of asphalt concrete were investigated after the marination.Indirect tensile strength test and retained stability test results were used to evaluate the marinating effect.As a result zycotherm dilution by weight of aggregate has changed the properties of asphalt mixture and improved to a great extent. From the results it can be concluded that rutting and fatigue problems decreased with a great range.

Predicting Field Permeability from Testing Hot-Mix Asphalt Specimens Produced by Superpave Gyratory Compactor

2005 ◽  
Vol 1929 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Kunnawee Kanitpong ◽  
Hussain Bahia ◽  
Jeffery Russell ◽  
Robert Schmitt
Keyword(s):  
Hot Mix Asphalt ◽  
Place Field ◽  
Simple Method ◽  
Air Voids ◽  
Good Relationship ◽  
Testing Procedures ◽  
Superpave Gyratory Compactor ◽  
Current Alternative ◽  
The Relationship ◽  
Better Than

This study was conducted to develop laboratory and field permeability testing procedures for design and quality control of Superpave® mixtures in Wisconsin. Sixteen mixes including fine-graded and coarse-graded mixes were evaluated. The in-place field permeability was measured by using the National Center for Asphalt Technology (NCAT) device, field cores were taken for measuring permeability in the laboratory by using the ASTM D5084 method, and laboratory compaction was used to prepare and test samples from loose mixtures recovered from the field. Two compaction procedures called Method A and Method B were used in this study to produce Superpave gyratory compacted (SGC) specimens that have thickness, air voids, and aggregate orientation similar to the field cores. Result indicates that Method B, based on the use of Ndesign gyrations for different sample sizes, can be used to produce samples that give permeability values similar to values measured for field cores. Results of this study also indicate a good relationship between field permeability (using the NCAT device) and lab permeability measured on field cores of fine-graded mixes with the amount passing No. 8 sieve (P8) higher than 45%. However, the relationship between field permeability and lab permeability measured on field cores of coarse-graded mix (P8 lower than 40%) is poor. It is concluded that the NCAT permeability device could possibly be used in the field for fine-graded mix (with P8 higher than 45%). However, to measure the field permeability of coarse-graded mix (P8 lower than 40%), there appears to be no current alternative better than taking field cores and testing them in the laboratory. For estimating permeability during mixture design, a simple method for preparing and testing permeability of SGC specimens and interpolating based on expected field density is introduced.

Hubungan Tingkat Pengetahuan dengan Presisi dan Akurasi Pemipetan Menggunakan Mikropipet Metode Forward

2019 ◽  
Vol 2 (1) ◽  
pp. 5
Author(s):  
Hendra Budi Sungkawa ◽  
Inten Ayu Kusuma
Keyword(s):  
Random Sampling ◽  
Simple Random Sampling ◽  
Support Service ◽  
Control Area ◽  
Test Results ◽  
Medical Support ◽  
Testing Procedures ◽  
Service Unit ◽  
Level Of Knowledge ◽  
Precision And Accuracy

Abstract : Pipetting is one of the most important activities in health laboratory analysis. Knowledge of pipetting must be owned by every health laboratory. Students of health analyst as a candidate of health laboratory who will become medical support service unit is expected to be able to do the pipetting precision and accurately. To get a thorough and accurate results then the results of the analysis must be located within a specifc control area and both in precision and accuracy. Precision and accuracy are responsible for analytical interpretation of test results and testing procedures. The method use in this research is the forward method by 61 people research samples which determined by simple random sampling. While the research design used was observational analytics. Based on the results of the research obtained the level of knowledge of respondents research is 71,38; precision pipetting 99,69% and accuracy pipetting 99,58%. From the data that has been obtained then analyzed statistically using tau kendau test. The result indicates that the level of knowledge and precision has a p=0,640 and correlation coeffcient of -0,044 so that the Ho is accepted, meaning there is no relationship between the level of knowledge and precision meaningful. Meanwhile, the level of knowledge and accuracy of the p=0,574 and correlation coeffcient value is -0,053 so that Ho is accepted, it means there is no relationship between the level of knowledge with accuracy. Abstrak: Pemipetan merupakan salah satu kegiatan yang sangat penting dalam analisa laboratorium kesehatan. Pengetahuan pemipetan harus dimiliki oleh setiap tenaga laboratorium kesehatan. Mahasiswa analis kesehatan sebagai calon tenaga laboratorium kesehatan yang akan menjadi unit pelayanan penunjang medis diharapkan mampu melakukan pemipetan dengan teliti dan akurat. Untuk mendapatkan hasil yang teliti dan akurat maka hasil analisa harus terletak di dalam daerah kontrol tertentu dan baik dalam presisi maupun akurasi. Presisi dan akurasi bertanggung jawab terhadap interpretasi analitik hasil pengujian serta prosedur pengujian. Metode yang dilakukan dalam penelitian ini adalah metode forward oleh sampel penelitian sebanyak 61 orang yang ditentukan secara simple random sampling. Sedangkan desain penelitian yang digunakan adalah observasional analitik. Berdasarkan dari hasil penelitian diperoleh nilai tingkat pengetahuan responden penelitian adalah 71,38; presisi pemipetan 99,69% dan akurasi pemipetannya 99,58%. Dari data yang telah didapatkan kemudian dianalisis secara statistik menggunakan uji kendal tau. Untuk tingkat pengetahuan dengan presisi didapatkan hasil nilai p=0,640 dan koefsien korelasi -0,044 sehingga Ho diterima, berarti tidak ada hubungan antara tingkat pengetahuan dan presisi. Untuk tingkat pengetahuan dengan akurasi nilai p=0,574 dan koefsien korelasi adalah -0,053 sehingga Ho diterima, berarti tidak ada hubungan antara tingkat pengetahuan dengan akurasi.

Study on the Dynamic Performance of Asphalt Concrete under Passive Confined Pressure

2012 ◽  
Vol 226-228 ◽  
pp. 1755-1759
Author(s):  
Hua Zhang ◽  
Fei Li ◽  
Yu Wei Gao
Keyword(s):  
Elastic Modulus ◽  
Asphalt Concrete ◽  
Poisson Ratio ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Dynamic Strength ◽  
Confining Pressure ◽  
Mechanical Behaviors ◽  
One Dimensional ◽  
Stress States

An improved passive confining pressure SHPB method was used to study the dynamic mechanical behaviors of asphalt concrete under quasi-one dimensional strain state. The effect of confining jacket material and its geometrical sizes on the confining pressure were discussed. The dynamic strength, dynamic modulus of elasticity and dynamic Poisson ratio of asphalt concrete were obtained. The influential rules of confining pressure on the dynamic properties were studied by comparing the stress-strain curves of asphalt concrete under different stress states. The study found that passive confining greater impact on the strength of asphalt concrete than elastic modulus and Poisson ratio, but the elastic modulus improved with the increase of confining pressure.

Shear Modulus and Damping Ratio of Gravel Material

2011 ◽  
Vol 105-107 ◽  
pp. 1426-1432 ◽  
Author(s):  
De Gao Zou ◽  
Tao Gong ◽  
Jing Mao Liu ◽  
Xian Jing Kong
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Dynamic Shear Modulus ◽  
Test Results ◽  
Dynamic Shear ◽  
Data Points ◽  
Shear Strain Amplitude

Two of the most important parameters in dynamic analysis involving soils are the dynamic shear modulus and the damping ratio. In this study, a series of tests were performed on gravels. For comparison, some other tests carried out by other researchers were also collected. The test results show that normalized shear modulus and damping ratio vary with the shear strain amplitude, (1) normalized shear modulus decreases with the increase of dynamic shear strain amplitude, and as the confining pressure increases, the test data points move from the low end toward the high end; (2) damping ratio increases with the increase of shear strain amplitude, damping ratio is dependent on confining pressure where an increase in confining pressure decreased damping ratio. According to the test results, a reference formula is proposed to evaluate the maximum dynamic shear modulus, the best-fit curve and standard deviation bounds for the range of data points are also proposed.

Watertightness, cracking resistance, and self-healing of asphalt concrete used as a water barrier in dams

2013 ◽  
Vol 50 (3) ◽  
pp. 275-287 ◽  
Author(s):  
Yingbo Zhang ◽  
Kaare Höeg ◽  
Weibiao Wang ◽  
Yue Zhu
Keyword(s):  
Asphalt Concrete ◽  
Leakage Rate ◽  
Strain Rates ◽  
Self Healing ◽  
Test Results ◽  
Direct Tension ◽  
Coefficient Of Permeability ◽  
Tension Tests ◽  
Laboratory Test Results ◽  
Cracked Specimens

The coefficient of permeability of hydraulic asphalt concrete is in the range 10−8–10−10 cm/s. Laboratory test results show that triaxial specimens in axial compression can undergo axial strains up to 18% without any significant increase in permeability until approaching the compressive strength. For temperatures between 5 and 20 °C and strain rates between 2 × 10−3%/s and 5 × 10−3%/s, conventional hydraulic asphalt concrete can tolerate 1%–3% tensile strains before cracking in direct tension tests and strains up to 3%–4% in bending. At 20 °C the tensile and bending strains at cracking are 2–4 times higher than those at 0 °C, and at −20 °C they are approximately 0.2% and 0.8%, respectively. Asphalt concrete possesses pronounced crack self-healing properties. In the experiments, the crack leakage rate dropped 1–4 orders of magnitude within a few hours and the cracked specimens regained 55% of the intact tensile strength after only 1 day of self-healing. In summary, the comprehensive series of laboratory tests documents that asphalt concrete has characteristics that make the material extremely well suited for use in impervious barriers in dams, and the test results reported herein can be of great use in barrier design.

Towards a more rational approach to chemical compatibility testing of clay

2002 ◽  
Vol 39 (3) ◽  
pp. 597-607 ◽  
Author(s):  
J K Kodikara ◽  
F Rahman ◽  
S L Barbour
Keyword(s):  
Boundary Condition ◽  
Hydraulic Conductivity ◽  
Rigid Wall ◽  
New Technique ◽  
Rational Approach ◽  
Lateral Strain ◽  
Test Results ◽  
Chemical Compatibility ◽  
Test Technique ◽  
Flexible Wall

Chemical compatibility tests using hydraulic conductivity testing with chemical permeants are normally undertaken to assess the integrity of compacted clayey liners used for waste containment. This paper highlights the fact that current routine methods of flexible wall and rigid wall testing techniques fail to represent the zero lateral strain boundary condition that is required to realistically represent the field situation. The test results indicate that flexible wall permeameters underestimate the likely increases in hydraulic conductivity due to chemicals, while the rigid wall permeameters can severely overestimate these effects. A new test technique, which incorporates the zero lateral strain condition in a simple manner, is presented. This technique involves the use of a rigid wall concept in a flexible wall permeameter. A split rigid mould is used to encase the soil specimen that is glued to the internal surfaces of the mould, to apply the zero lateral strain boundary condition. The new technique is shown to be suitable for both chemical compatibility and desiccation testing. The tests were undertaken with varying concentrations of saline water, methanol, and landfill leachate. The test results indicate that the new technique produces results that fall between the results obtained from flexible wall and rigid wall permeameters. It is argued that the new test technique provides a more rational approach for chemical compatibility testing than the current rigid wall and flexible wall techniques.Key words: soil, hydraulic conductivity, chemical compatibility, landfill, permeameter, boundary condition.

A Change of Undrain Shear Strength of Soft Ground during Consolidation Process

2014 ◽  
Vol 513-517 ◽  
pp. 269-272
Author(s):  
Yeong Mog Park ◽  
Ik Joo Um ◽  
Norihiko Miura ◽  
Seung Cheol Baek
Keyword(s):  
Shear Strength ◽  
Soft Clay ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Test Results ◽  
Exponential Equation ◽  
Consolidation Process ◽  
Degree Of Consolidation ◽  
Clay Ground ◽  
Strength Increment

The purpose of this study is to investigate the undrain shear strength increment during consolidation process of soft clayey soils. Thirty kinds of laboratory triaxial tests have been performed using undisturbed and remolded Ariake clay samples with different degree of consolidation and 5 kinds of confining pressure. Test results show that well known linear equation proposed by Yamanouchi et al.(1982) is overestimated the strength of undisturbed soft clay ground in the process of consolidation. A new simple and reasonable exponential equation proposed in this paper.

Sign in / Sign up

Export Citation Format

Share Document