Laboratory and Economic Evaluations of Thin Lift Asphalt Overlay for Pavement Preservation

2016 ◽  
Vol 5 (1) ◽  
pp. 20160025
Author(s):  
J. Habbouche ◽  
E. Y. Hajj ◽  
P. E. Sebaaly
Keyword(s):  
Economic Evaluations ◽  
Pavement Preservation ◽  
Asphalt Overlay

High-Performance Thin-Lift Overlays with High Reclaimed Asphalt Pavement Content and Warm-Mix Asphalt Technology

2012 ◽  
Vol 2293 (1) ◽  
pp. 18-28 ◽  
Author(s):  
Walaa S. Mogawer ◽  
Alexander J. Austerman ◽  
Robert Kluttz ◽  
Michael Roussel
Keyword(s):  
High Performance ◽  
Asphalt Pavement ◽  
Warm Mix Asphalt ◽  
Asphalt Binders ◽  
Reclaimed Asphalt Pavement ◽  
Moisture Susceptibility ◽  
Reclaimed Asphalt ◽  
Pavement Preservation ◽  
Asphalt Overlay ◽  
Structural Capacity

A high-performance thin asphalt overlay (HPThinOL) is specified as having a thickness of 1 in. or less and is used in applications requiring high levels of rutting and fatigue resistance. HPThinOLs are used as a pavement preservation strategy and are placed on pavements that have remaining structural capacity that is expected to outlive that strategy. Current specifications for HPThinOLs generally call for a polymer-modified asphalt (PMA). However, PMA binders are more expensive than unmodified asphalt binders. This expense, coupled with the higher binder content requirement generally associated with HPThinOL, could lead to an initial higher cost in relation to other pavement preservation strategies. Although the higher initial cost can be offset by incorporating high amounts of reclaimed asphalt pavement (RAP), the use of high amounts of RAP in PMA mixtures might adversely affect the mixture performance (stiffness, cracking, or workability). Warm-mix asphalt (WMA) technology may improve the workability of HPThinOL that incorporates high RAP content and PMA binders. This study evaluated the effect of PMA binders, high RAP content, and WMA technology on the stiffness, resistance to reflective cracking, moisture susceptibility, and workability of HPThinOL mixtures. PMA binders and high RAP content increased the stiffness of HPThinOL significantly; however, the use of WMA technology lowered mixture stiffness and improved workability. PMA may improve the cracking resistance, moisture susceptibility, and rutting resistance of high-RAP HPThinOL mixtures, depending on whether a WMA technology is used.

scholarly journals Manual for Thin Asphalt Overlays

2020 ◽  
Author(s):  
Lerose Lane ◽  
R. Gary Hicks ◽  
DingXin Cheng ◽  
Erik Updyke
Keyword(s):  
Good Condition ◽  
Technical Information ◽  
Functional Condition ◽  
Pavement Preservation ◽  
Asphalt Overlay ◽  
The 1960S ◽  
Senate Bill 1 ◽  
Local Agencies ◽  
Asphalt Overlays ◽  
Design And Construction

This manual presents best practices on project selection, mix design, and construction to ensure a superior product when constructing thin asphalt overlays. Experience shows these treatments provide excellent performance when placed on pavements in fair to good condition using proper construction techniques. Though sometime referred to by other names, thin asphalt overlays have been widely used for pavement preservation throughout the world for over 50 years. Limited infrastructure funding at the local, state, and federal levels has resulted in greater emphasis on the use of pavement preservation techniques to extend pavement life and reduce maintenance costs. Thin asphalt overlays are one of many preventative maintenance treatments. Thin asphalt overlays are placed directly on existing pavement and can range from 1/2 inch to 1 1/2 inches in thickness. Thin asphalt overlays have proven to be an economical means for maintaining and improving the functional condition of an existing pavement since the 1960s. Specifically, this manual provides guidance for engineers regarding where and when to use thin asphalt overlays including: (1) Types and variations of thin overlays; (2) Materials and the design process; (3) Construction; (4) Quality Assurance; and (5) Troubleshooting. This chapter by chapter guidance enables an Agency’s engineers to design and construct a successful thin asphalt overlay project to completion. This manual is one of four new manuals prepared by the California Pavement Preservation Center (CP2Center) using funding from California Senate Bill 1 (SB-1), passed in April 2017. The other three manuals provide detailed design and construction information for (1) chip seals, (2) slurry surfacing, and (3) Cape seals. The creation of these manuals was a task funded entirely from SB-1 monies for the purpose of disseminating training and technical information on highway pavement preservation to local agencies throughout California.

Rehabilitation and Upgrading of the Beni Suef City Wastewater Treatment Plant

1990 ◽  
Vol 22 (7-8) ◽  
pp. 131-138
Author(s):  
Ahmed Fadel
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Primary Treatment ◽  
High Rate ◽  
Shock Load ◽  
Economic Evaluations ◽  
Activated Sludge Process ◽  
Trickling Filter

Many of Egypt's cities have existing treatment plants under operation that have been constructed before 1970. Almost all of these treatment plants now need rehabilitation and upgrading to extend their services for a longer period. One of these plants is the Beni Suef City Wastewater Treatment Plant. The Beni Suef WWTP was constructed in 1956. It has primary treatment followed by secondary treatment employing intermediate rate trickling filters. The BOD, COD, and SS concentration levels are relatively high. They are approximately 800, 1100, and 600 mg/litre, respectively. The Beni Suef city required the determination of the level of work needed for the rehabilitation and upgrading of the existing 200 l/s plant and to extend its capacity to 440 l/s at year 2000 A description of the existing units, their deficiencies and operation problems, and the required rehabilitation are presented and discussed in this paper. Major problems facing the upgrading were the lack of space for expansion and the shortage of funds. It was, therefore, necessary to study several alternative solutions and methods of treatment. The choice of alternatives was from one of the following schemes: a) changing the filter medium, its mode of operation and increasing the number of units, b) changing the trickling filter to high rate and combining it with the activated sludge process, for operation by one of several possible combinations such as: trickling filter-solids contact, roughing filter-activated sludge, and trickling filter-activated sludge process, c) dividing the flow into two parts, the first part to be treated using the existing system and the second part to be treated by activated sludge process, and d) expanding the existing system by increasing the numbers of the different process units. The selection of the alternative was based on technical, operational and economic evaluations. The different alternatives were compared on the basis of system costs, shock load handling, treatment plant operation and predicted effluent quality. The flow schemes for the alternatives are presented. The methodology of selecting the best alternative is discussed. From the study it was concluded that the first alternative is the most reliable from the point of view of costs, handling shock load, and operation.

scholarly journals Correction to: Economic Evaluations of Childhood Hearing Loss Screening Programmes: A Systematic Review and Critique

2019 ◽  
Vol 17 (3) ◽  
pp. 419-419
Author(s):  
Rajan Sharma ◽  
Yuanyuan Gu ◽  
Teresa Y. C. Ching ◽  
Vivienne Marnane ◽  
Bonny Parkinson
Keyword(s):  
Systematic Review ◽  
Hearing Loss ◽  
Economic Evaluations ◽  
Childhood Hearing Loss

Looking forward and looking backward: Economic evaluations and regime support in China

Politics ◽  
2021 ◽  
pp. 026339572198954
Author(s):  
Yida Zhai
Keyword(s):  
Economic Evaluation ◽  
National Economy ◽  
Authoritarian Regimes ◽  
Economic Situation ◽  
Economic Conditions ◽  
Economic Evaluations ◽  
Age Cohorts ◽  
Psychological Mechanism ◽  
The Stability ◽  
Regime Support

It is widely acknowledged that the economic situation is of vital importance for the stability of an authoritarian regime, but it is rarely known how the public’s economic evaluation contributes to such outcomes. This study examines the effects of citizens’ retrospective and prospective evaluations of their household economic situation and the national economy on the level of regime support in China. The findings show that the national economy outweighs household economic conditions in its effects on the public’s support of the regime. However, the gap between evaluations of the national economy and individual economic situations debilitates regime support. The population in different age cohorts has distinct patterns of relationships between retrospective and prospective economic evaluations and regime support. This study elucidates the political-psychological mechanism of the public’s economic evaluation affecting regime support, and the ruling strategy in authoritarian regimes of manipulating this evaluation.

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