Variations in Composition and Rheology of Bituminous Crack Sealants for Pavement Maintenance

2005 ◽  
Vol 1933 (1) ◽  
pp. 107-112 ◽  
Author(s):  
J.-F. Masson ◽  
Peter Collins ◽  
Sladana Bundalo-Perc ◽  
John R. Woods ◽  
Imad Al-Qadi
Keyword(s):  
Asphalt Concrete ◽  
Preventive Maintenance ◽  
Field Performance ◽  
Concrete Pavements ◽  
Past Performance ◽  
Pavement Maintenance ◽  
The Difference ◽  
And Performance ◽  
Over Time ◽  
Selection Of

Bituminous crack sealants are used for the preventive maintenance of asphalt concrete pavements. The selection of a durable sealant can be difficult, however, mainly because of the lack of correlation between standard sealant specifications and field performance. Hence, an approved list of materials based on past performance is sometimes used to select sealants. However, sealant durability and performance vary over time. To investigate the effect of sealant lot variation on sealant properties, six lots of two sealants from different suppliers were analyzed for filler and polymer contents and rheological response. It was found that the difference in composition and rheology between lots can be similar to that between sealants produced by different manufacturers. Hence, sealant lot-to-lot variation can partly explain the variation in the field performance of sealants. Therefore, lists of approved products drawn from the field performance of past years are ineffective in the selection of sealants for future maintenance. The application of segregated sealants was also investigated, including assessing the effect of melter stirring on sealant homogeneity and measuring the segregation of sealant upon cooling. It was found that sealants do not segregate after their application and subsequent cooling and that a rapid circumferential stirring of 25 revolutions per minute in the heating kettle allowed for the remixing of a segregated sealant.

Diagnosis and classification criteria

2018 ◽  
Author(s):  
Laura C. Coates ◽  
William J. Taylor
Keyword(s):  
Signs And Symptoms ◽  
Classification Criteria ◽  
Design Function ◽  
Diagnosis And Classification ◽  
Axial Disease ◽  
Different Populations ◽  
The Difference ◽  
And Performance ◽  
Over Time

This chapter covers diagnosis and classification of psoriatic arthritis (PsA). Firstly the difference between diagnosis and classification criteria in terms of their design, function, and performance is discussed. The diagnostic clues of PsA are summarized: risk factors for development of arthritis amongst patients with psoriasis, signs, and symptoms of articular, entheseal and axial disease, and relevant investigations. Older classification criteria for PsA are discussed along with later modifications. The development of the CASPAR criteria is described and subsequent studies assessing the accuracy of the CASPAR criteria in different populations are then summarized. How PsA fits within the broader family of spondyloarthritides (SpA) and the performance of CASPAR compared to SpA criteria is outlined. Different subtypes of PsA, as well as the evolution of individual patients through subtypes over time, are described. Finally future proposals to develop the ‘stem’ of CASPAR to define ‘inflammatory articular, entheseal or axial disease’ are summarized.

Implementation Feasibility of Asphalt Concrete–Overlaid Portland Cement Concrete Pavement Rehabilitation Guidelines

1997 ◽  
Vol 1568 (1) ◽  
pp. 155-164
Author(s):  
Kathleen T. Hall ◽  
Amy Schutzbach
Keyword(s):  
Portland Cement ◽  
Asphalt Concrete ◽  
Concrete Pavements ◽  
Remaining Life ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Pavement Rehabilitation ◽  
Cement Concrete Pavement ◽  
Rehabilitation Strategy ◽  
Selection Of

Illinois Highway Research Study IHR-532 was conducted to develop project-level guidelines for evaluation, rehabilitation selection, and rehabilitation design for existing asphalt concrete–overlaid portland cement concrete (AC/PCC) pavements in Illinois. Use of these guidelines depends on data that are not normally available for network-level analysis. A study was conducted to assess the feasibility of implementing these guidelines in network-level decision making and to assess the effects that implementing these guidelines for selection of rehabilitation methods for existing asphalt-overlaid concrete pavements would have on the overall rehabilitation budget requirements for a district network of Interstate pavements, the overall network condition, and pavement network remaining life. These objectives were met by comparing the IHR-532 rehabilitation strategy (which identifies one or more rehabilitation options) with the Illinois Department of Transportation’s current rehabilitation policy, which is an AC overlay thickness of 83 mm (3.25 in.). This feasibility analysis indicated that the selection of the preferred rehabilitation strategy was strongly related to the type and condition of the existing pavement. It also indicated that the IHR-532 rehabilitation strategy and the single rehabilitation strategy yielded similar networkwide results when compared on the basis of average condition at the end of the analysis period. However, the IHR-532 rehabilitation strategy indicated greater benefit than the single rehabilitation strategy, at any budget level, when compared on the basis of network average remaining life at the end of the analysis period.

Gas Turbine Field Performance Determination: Sources of Uncertainties

2000 ◽  
Author(s):  
M. Pinelli ◽  
P. R. Spina
Keyword(s):  
Gas Turbine ◽  
Estimation Error ◽  
A Priori ◽  
Field Performance ◽  
Thermodynamic Cycle ◽  
Field Measurements ◽  
Characteristic Parameters ◽  
And Performance ◽  
Selection Of

This paper presents an analysis of the uncertainties in the determination of gas turbine health, which arise by using a method of Gas Path Analysis. This method uses field measurements to estimate, through a mathematical model of the gas turbine thermodynamic cycle, the characteristic geometric and performance parameters, which are indices of gas turbine health. The investigated sources of uncertainties are the inaccuracy of measurements and the necessity of fixing a priori a number of characteristic parameters. This fact implies that variations occurring on these parameters in the actual gas turbine cause an estimation error on the characteristic parameters used as problem variables. The analysis leads to the selection of the appropriate measurements to be used in the gas turbine health determination and identification of both the most critical measurements and parameters.

scholarly journals Changes in Spinal Instability After Combined Therapy of Conventional Radiotherapy and Bone Modifying Agents for Painful Vertebral Bone Metastases

2021 ◽  
Author(s):  
Eiji Nakata ◽  
Shinsuke Sugihara ◽  
Yoshifumi Sugawara ◽  
Ryuichi Nakahara ◽  
Shouta Takihira ◽  
...  
Keyword(s):  
Combined Therapy ◽  
Spinal Metastases ◽  
Spinal Instability ◽  
Vertebral Metastases ◽  
Conventional Radiotherapy ◽  
Potential Risk Factors ◽  
The Difference ◽  
Over Time ◽  
Selection Of

Abstract Precise assessment of spinal instability is critical at the beginning and after radiotherapy for selection of the treatment and evaluating the effectiveness of radiotherapy. We investigated changes of spinal instability after radiotherapy and examined potential risk factors for the difference of the outcome of spinal instability for painful spinal metastases. We evaluated 81 patients who received radiotherapy for painful vertebral metastases in our institution between 2012 and 2016. The pain at the vertebrae was assessed. Radiological responses of irradiated vertebrae were assessed by computed tomography. Spinal instability was assessed by Spinal Instability Neoplastic Score (SINS). Follow-up assessments were done at the start of radiotherapy and at 1, 2, 3, 4, and 6 months after radiotherapy. At each of one to six months, pain disappeared in 62%, 84%, 93%, 98%, and 100% of patients. The median SINS were 8, 7, 6, 5, 5, and 4 at the beginning of radiotherapy and after 1, 2, 3, 4, and 6 months, respectively, which significantly decreased over time (P < 0.001). Multivariate analysis revealed that PLISE was the only risk factor for spinal instability at one month. In conclusion, spinal instability significantly improved over time after radiotherapy. Clinicians should take attention to PLISE in the radiotherapy of vertebral metastases.

Aggregate Toughness/Abrasion Resistance and Durability/Soundness Tests Related to Asphalt Concrete Performance in Pavements

1998 ◽  
Vol 1638 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Yiping Wu ◽  
Frazier Parker ◽  
Prithvi S. Kandhal
Keyword(s):  
Asphalt Concrete ◽  
Abrasion Resistance ◽  
Laboratory Tests ◽  
Field Performance ◽  
Strong Relationship ◽  
Test Methods ◽  
Review Of Literature ◽  
Aggregate Properties ◽  
And Performance ◽  
Transportation Agencies

Numerous tests have been developed that empirically characterize aggregate without, necessarily, having a strong relationship to the performance of the final products incorporating these aggregates. This seems to be particularly true for aggregate toughness and abrasion resistance and durability and soundness. Toughness/abrasion resistance and durability/soundness tests for characterizing aggregate used in asphalt concrete were identified and evaluated, and those test methods that best correlate with field performance were determined. Based on a review of literature and specifications, laboratory tests for characterizing aggregate toughness/abrasion resistance and durability/soundness were selected. Sixteen aggregate sources with poor to good performance histories were identified for evaluation with the selected suite of tests. Performance histories of pavements containing these aggregates in asphalt concrete layers were established through personal contacts with state transportation agencies and performance evaluation questionnaires. Aggregate properties from laboratory tests were correlated with field performance. The micro-deval and magnesium sulfate soundness tests provide the best correlations with field performance of asphalt concrete and are recommended for characterizing aggregate toughness/abrasion resistance and durability/soundness.

Gas Turbine Field Performance Determination: Sources of Uncertainties

2000 ◽  
Vol 124 (1) ◽  
pp. 155-160 ◽  
Author(s):  
M. Pinelli ◽  
P. R. Spina
Keyword(s):  
Gas Turbine ◽  
Estimation Error ◽  
A Priori ◽  
Field Performance ◽  
Thermodynamic Cycle ◽  
Field Measurements ◽  
Characteristic Parameters ◽  
And Performance ◽  
Selection Of

This paper presents an analysis of the uncertainties in the determination of gas turbine health, which arise by using a method of gas path analysis. This method uses field measurements to estimate, through a mathematical model of the gas turbine thermodynamic cycle, the characteristic geometric and performance parameters, which are indices of gas turbine health. The investigated sources of uncertainties are the influence of measurement accuracy and the a priori selection of the characteristic parameters that have to be considered constant during the calculation. This fact implies that variations occurring on these parameters in the actual gas turbine cause an estimation error on the characteristic parameters used as problem variables. The analysis leads to the selection of the appropriate measurements to be used in the gas turbine health determination and to the identification of both the most critical measurements and parameters.

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