The Use of Bitumen Linear Viscoelastic Properties to Assess Rutting Sensitivity

2014 ◽  
Vol 567 ◽  
pp. 755-762
Author(s):  
Salah E. Zoorob ◽  
Ibrahim B. Kamaruddin ◽  
Napiah Madzlan
Keyword(s):  
Energy Equation ◽  
Empirical Relationship ◽  
Stored Energy ◽  
Theoretical Derivation ◽  
The Us ◽  
Modified Binders ◽  
Recent Developments ◽  
Linear Viscoelastic ◽  
Modified Binder ◽  
Performance Grading

The use of viscosity temperature relationships to predict creep performance of road bitumens have been shown to be inadequate in particular with respect to the analysis of polymer modified binders. In this paper we explore the origins of the US Strategic Highway Research Programmebinder performance grading system and detail two examples of more recent developments towards improved creep characterisation.Starting from first principles, an equation to analyse the ratio of dissipated to stored energy during sinusoidal loading of viscoelastic bitumen was derived. The energy equation was contrasted with an empirical relationship proposed by Anderson D.A., and with a second more theoretical derivation proposed by Shenoy A.Using frequency sweep data from a conventional 40/50 pen grade bitumen and a proprietary SBS modified binder, the applicability of the energy equation was subsequently compared to the two aforementioned post-SHRP creep relations. Recommendations are made regarding the suitability of the proposed relations in ranking bitumen creep performance.

scholarly journals Should Women Consult Health Agencies in Matters of Birth Control and Contraception?

2020 ◽  
Vol 1 (2) ◽  
pp. 28-37
Author(s):  
Kraetschmer K
Keyword(s):  
Birth Control ◽  
Economic Perspective ◽  
Safety And Efficacy ◽  
Contraceptive Devices ◽  
Scholarly Publications ◽  
Health Agencies ◽  
The Us ◽  
Other Information ◽  
Recent Developments ◽  
Harmful Effects

Background and Aim: On the background of recent developments revealing the harmful effects of contraceptive devices which are recommended by health agencies the paper aims at analyzing publications and other information material emanating from these agencies. This analysis – guided by the bioethical principle of informed consent — focuses on flawed science, ambiguous language, and misleading data. Method and Material: The method consists of collecting and analyzing information provided by health agencies for consumers inquiring about the safety and efficacy of contraceptive products. The material comprises documents, charts, leaflets and other publications emanating from the most authoritative and most frequently consulted health agencies, in particular those active in the US and European countries. Results and Implications: As a result of the investigation women must be advised to consult only a selected number of health agencies, especially those which take into account findings of pharmacovigilance, pharmaceutical vigilance, and scholarly publications focusing on the safety of contraception. The implications from an economic perspective are the discontinuation of funding through taxpayer money for those health agencies which continue to disseminate flawed science and demonstrate incompetence in questions about the safety of contraception.

Russia: facing west or east

2017 ◽  
Author(s):  
Jude Woodward
Keyword(s):  
Foreign Policy ◽  
East Asia ◽  
21St Century ◽  
Us Foreign Policy ◽  
The West ◽  
Uncertain Outcome ◽  
Policy Goals ◽  
The Us ◽  
Recent Developments ◽  
Post War

This chapter reviews US-China-Russia relations in the post-war period, and considers how recent developments affect prospects for the US ‘pivot’. It explains why those driving US foreign policy towards China see the confrontation with Russia in Ukraine as a dangerous and diversionary adventure, leading to Sino-Russian convergence, distracting US attention from East Asia and undermining confidence among the US’s Asian allies of its commitment to the region. It is argued that if the US is to maintain primacy in the 21st century, it must subordinate other foreign policy goals to the paramount objective of containing China’s rise. The US’s failure to do this, instead pitting itself against both Putin in the West and China in the East, means it has driven Russia and China together, quite possibly sacrificing its vital need to contain China for a lesser goal of uncertain outcome in Ukraine.

A Comprehensive Treatise of the High Temperature Specification Parameter |G*|/(1-(1/tanδsinδ)) for Performance Grading of Asphalts

2004 ◽  
Vol 14 (6) ◽  
pp. 303-314 ◽  
Author(s):  
Aroon Shenoy
Keyword(s):  
High Temperature ◽  
Field Performance ◽  
Performance Data ◽  
Asphalt Binders ◽  
Theoretical Derivation ◽  
Comprehensive Treatise ◽  
Actual Field ◽  
Rutting Behavior ◽  
Performance Grading ◽  
Unrecovered Strain

Abstract The term |G*|/(1-(1/tanδ sinδ)) has been suggested as one of the best candidates for the replacement of the Super-pave specification parameter |G*|/sinδ, which has been found to be inadequate in rating polymer-modified binders for high temperature performance grading. This refinement of the Superpave specification parameter evolved through a theoretical derivation based on fundamental concepts. It was shown to be more sensitive to the variations in the phase angle δ than the original Superpave specification parameter. It thus described the unrecovered strain in the asphalt binders more accurately, and hence related to actual field performance data. This article provides a comprehensive treatise of the parameter |G*|/(1-(1/tanδ sinδ)) giving details of its derivation, salient features that are attributed to its success, comparison with actual field performance data for validation and a one-on-one comparison with the existing parameter |G*|/sinδ. It is shown that for all available field data, the parameter |G*|/(1-(1/tanδ sinδ)) does a better job in correlating with the rutting behavior than the parameter |G*|/sinδ for unmodified as well as modified asphalts. Since it is obtained in the same manner as the parameter |G*|/sinδ through the determination of |G*| and δ from a stress-controlled or strain-controlled dynamic shear rheometer, it means that no retraining of technicians and staff is required and implementation for the use of this parameter is immediate, thereby saving enormous amount of time and money. This parameter has the further advantage of being in a form easily adaptable to modeling, and thereby directly applicable for pavement design purposes.

Combination Drug Therapy: A Strategy for Aggressive Lipid Modification

2005 ◽  
Vol 40 (11) ◽  
pp. 954-962
Author(s):  
James M. Backes ◽  
Patricia A. Howard
Keyword(s):  
Cardiovascular Disease ◽  
Drug Therapy ◽  
Clinical Outcome ◽  
Combination Drug Therapy ◽  
Lipid Modification ◽  
Combination Drug ◽  
Cardiovascular Pharmacotherapy ◽  
The Us ◽  
Prevention And Treatment ◽  
Recent Developments

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the US, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on prevention and treatment — if they keep current with developments in drug therapy.

The Evolving Role of Angiotensin Receptor Blockers in Heart Failure

2002 ◽  
Vol 37 (5) ◽  
pp. 474-482
Author(s):  
Patricia A. Howard
Keyword(s):  
Heart Failure ◽  
Cardiovascular Disease ◽  
Angiotensin Receptor Blockers ◽  
Angiotensin Receptor ◽  
Cardiovascular Pharmacotherapy ◽  
The Us ◽  
Prevention And Treatment ◽  
Recent Developments ◽  
Receptor Blockers

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the US, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on the prevention and treatment of cardiovascular disease—if they keep current with developments in drug therapy.

An Overview and Critique of US Immigration and Asylum Policies in the Trump Era

2019 ◽  
Vol 7 (3) ◽  
pp. 92-102
Author(s):  
Paul Wickham Schmidt
Keyword(s):  
Legal Framework ◽  
Constitutional Rights ◽  
Federal Law ◽  
Executive Summary ◽  
The Us ◽  
Recent Developments ◽  
State And Local ◽  
Immigrant Detention ◽  
Immigration And Asylum ◽  
Us Immigration

Executive Summary This article provides an overview and critique of US immigration and asylum policies from the perspective of the author’s 46 years as a public servant. The article offers a taxonomy of the US immigration system by positing different categories of membership: full members of the “club” (US citizens), associate members (lawful permanent residents, refugees, and “asylees”), friends (nonimmigrants and holders of temporary status), and persons outside the club (the undocumented). It describes the legal framework that applies to these distinct populations and recent developments in federal law and policy that relate to them. It also identifies a series of cross-cutting issues that affect these populations, including immigrant detention, immigration court backlogs, state and local immigration policies, and constitutional rights that extend to noncitizens. It ends with a series of recommendations for reform of the US asylum system, and a short conclusion.

THE INFLUENCE OF POLYMER ON RHEOLOGICAL AND THERMO OXIDATIVE AGING PROPERTIES OF MODIFIED BITUMEN BINDERS

2017 ◽  
Vol 79 (6) ◽  
Author(s):  
Nura Bala ◽  
Ibrahim Kamaruddin ◽  
Madzlan Napiah
Keyword(s):  
Softening Point ◽  
Storage Stability ◽  
Elastic Behavior ◽  
Modified Bitumen ◽  
Oxidative Aging ◽  
Modified Binders ◽  
Aging Resistance ◽  
Lower Temperature ◽  
Modified Binder ◽  
Temperature Susceptibility

Polymer modified bitumen (PMB) has been used for many years to improve the performance of asphalt concretes against premature pavement defects. In this research, modified samples were prepared with 2%, 3%, 4%, 5% and 6% Linear Low Density Polyethylene (LLDPE) polymer by weight of bitumen binder. The influence of LLDPE polymer was evaluated through binder properties test which includes penetration, softening point, storage stability, temperature susceptibility, rutting, fatigue and thermal oxidative aging resistance from a dynamic shear rheometer (DSR) measurements at a temperature of 20 OC to 60 OC. Results show that LLDPE polymer has a significant effect on binder properties. Penetration decreases and softening point increases with increasing LLDPE content on the modified binder after aging, which implies LLDPE improves the thermo oxidative aging resistance of the binder. Furthermore, the storage stability test shows that at higher LLDPE concentrations phase separation may occur. DSR analysis shows that modified binders have lower temperature susceptibility and higher aging resistance with increased stiffness and elastic behavior compared with unmodified binders. In addition, modified binders show enhanced resistance against high temperature rutting and at low temperature fatigue performance. It was found that the optimum LLDPE content is 6%.

scholarly journals EFFECT OF RH-WMA ADDITIVE ON ENGINEERING PROPERTIES OF BITUMEN PG-76/KESAN BAHAN TAMBAH RH-WMA KE ATAS SIFAT- SIFAT KEJURUTERAAN BITUMEN PG-76

2019 ◽  
Vol 81 (4) ◽  
Author(s):  
Gatot Rusbintardjo ◽  
Sitti Salmah Abdul Wahab ◽  
Faridah Hanim Khairuddin ◽  
Ahmad Nazrul Hakimi Ibrahim ◽  
Nur Izzi Md Yusoff ◽  
...  
Keyword(s):  
Contact Angle ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Warm Mix Asphalt ◽  
Molecular Structures ◽  
Engineering Properties ◽  
Morphological Properties ◽  
Modified Binders ◽  
Modified Binder

Pavement failure phenomena is normally caused by low quality of mixture materials, especially bitumen. The modification of bitumen is one of the alternatives to improve the performance of the material. Therefore, this study was conducted to investigate the performance of a polymer-modified binder (PG-76) with the addition of different percentages of Reduce Heat-Warm Mix Asphalt (RH-WMA) at 1, 2, 3, 4 and 5 % (by-weight of binder). Several testings such as penetration, softening point and ductility tests were conducted to determine the physical properties of PG-76 and RH-WMA modified binders. The molecular structures of the materials were analysed using Fourier transform infrared spectroscopy (FTIR) test while the contact angle test was conducted to investigate the type of binder’s surface. In addition, an optical microscopy test was carried out to determine the morphological properties of the modified binders. Results show that the PG-76’s hardness decreases with the increasing of RH-WMA percentage, but the ductility values are still within the specification. The FTIR test shows an increase of RH-WMA percentage does not provide a significant reaction of the binder and the original properties of the materials remain. The morphology test shows that all percentage of RH-WMA selected are well dispersed in bitumen PG-76. Based on the contact angle results, all the PG-76 and RH-WMA modified binders fall into hydrophobic category.

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