scholarly journals Probability-Based Concrete Carbonation Prediction Using On-Site Data

2020 ◽  
Vol 10 (12) ◽  
pp. 4330
Author(s):  
Hyunjun Jung ◽  
Seok-Been Im ◽  
Yun-Kyu An
Keyword(s):  
Probabilistic Approach ◽  
Concrete Structures ◽  
Design Parameters ◽  
Degree Of Hydration ◽  
Concrete Carbonation ◽  
Remaining Service Life ◽  
Long Term Performance ◽  
Term Performance ◽  
Prediction Approach

This study proposes a probability-based carbonation prediction approach for successful monitoring of deteriorating concrete structures. Over the last several decades, a number of researchers have studied the concrete carbonation prediction to estimate the long-term performance of carbonated concrete structures. Recently, probability-based durability analyses have been introduced to precisely estimate the carbonation of concrete structures. Since the carbonation of concrete structures, however, can be affected by material compositions as well as various environmental conditions, it is still a challenge to predict concrete carbonation in the field. In this study, the Fick’s first law and a Bayes’ theorem-based carbonation prediction approach is newly proposed using on-site data, which were obtained over 19 years. In particular, the effects of design parameters such as diffusion coefficient, concentration, absorption quantity of CO2, and the degree of hydration have been thoroughly considered in this study. The proposed probabilistic approach has shown a reliable prediction of concrete carbonation and remaining service life.

Effect of Stent Design Parameters on Coronary Artery Flow

2009 ◽  
Author(s):  
Satyaprakash Karri ◽  
Stephen Peter ◽  
Pavlos P. Vlachos
Keyword(s):  
Thrombus Formation ◽  
Design Parameters ◽  
Radius Of Curvature ◽  
Stent Design ◽  
Endovascular Stents ◽  
Long Term Performance ◽  
Artery Flow ◽  
Term Performance ◽  
Realistic Geometries

The most widely accepted modality for treating diseased arteries is the implantation of endovascular stents. Stents are metallic wireframe devices used to reopen clogged arteries. Despite their widespread use, problems persist post-implantation of these devices beginning with sub-acute thrombus formation followed by inflammation, proliferation and remodeling [1]. The specific stent design and its design parameters profoundly impact the hemodynamic environment of the stent [2], in turn affecting thrombus accumulation between struts and thus restenosis [3]. Prior research examining the hemodynamic effects of stents has been performed in simplified geometries [4] however the effects of stent design parameters such as strut thickness and crown radius of curvature or analysis in realistic geometries is generally lacking. A more thorough understanding of the effect of a stent’s geometric parameters on the arterial flow will provide insight into their long-term performance and will lead to better design.

Input Parameters for the Mechanistic-Empirical Design of Full-Depth Reclamation Projects

2021 ◽  
pp. 036119812110179
Author(s):  
Vishwa V. Beesam ◽  
Cristina Torres-Machi
Keyword(s):  
Pavement Design ◽  
Design Parameters ◽  
Future Research ◽  
Limited Information ◽  
Full Depth Reclamation ◽  
Input Parameters ◽  
Current Design ◽  
Long Term Performance ◽  
Term Performance

Cold recycling technologies such as full-depth reclamation (FDR) are sustainable and cost-effective techniques for pavement rehabilitation that reduce environmental impacts and construction costs and time. The limited information available on the material properties of FDR mixtures and their characterization in mechanistic-empirical (M-E) pavement design hinders the full deployment of FDR. Previous research has found current M-E default values to be non-representative and overly conservative, leading to an underestimation of the true performance capabilities of FDR materials. To address this gap, this paper analyzes the performance of 11 FDR sites constructed throughout Colorado, U.S., and compares their long-term performance with M-E predictions. The objective of this paper is to recommend input values for the M-E design of FDR base materials that result in reliable predictions of FDR long-term performance. The analysis includes both non-stabilized and emulsion-stabilized FDR projects. Both initial International Roughness Index (IRI) and resilient modulus were found to have a significant impact on M-E predictions and were calibrated in a two-step process. The proposed input parameters lead to a conservative design of FDR projects and result in improved IRI predictions compared with the ones derived from current design criteria. With the current design parameters, IRI predictions were, on average, overestimated by 51 in./mi, whereas the proposed input parameters make it possible to reduce this difference to 17 in./mi. Future research is needed to improve current models in M-E pavement design software to adequately model cold in-place recycled layers such as FDR.

Review of the performance of full-scale MBR plants: design, operation and on-site experimental data

2010 ◽  
Vol 5 (2) ◽  
Author(s):  
S.K. Pattanayak ◽  
S. Chang ◽  
M. Theodoulou ◽  
V. Mahendraker
Keyword(s):  
Full Scale ◽  
Design Parameters ◽  
Plant Design ◽  
Treatment Technology ◽  
Wide Range ◽  
Pre Treatment ◽  
Long Term Performance ◽  
Term Performance ◽  
Removal System

The membrane bioreactor (MBR) process has become an effective alternative wastewater treatment technology that produces effluent with excellent quality. Globally, a wide range of municipal and industrial MBR plants are in operation, varying both in size and complexity. The objective of this investigation was to develop a better understanding of the long term performance of MBR plants. To achieve this objective, eight full-scale municipal MBR plants were examined. The methodology included a review of plant design parameters, pre-treatment system, biological operation, membrane operation, disinfection system and nutrient removal system. In addition, on-site tests were done on permeate, final effluent and mixed liquor to understand MBR performance.

Long-term performance and life-cycle-cost benefits of cathodic protection of concrete structures using galvanic anodes

2021 ◽  
Vol 42 ◽  
pp. 102467
Author(s):  
Naveen Krishnan ◽  
Deepak K. Kamde ◽  
Zameel Doosa Veedu ◽  
Radhakrishna G. Pillai ◽  
Dhruvesh Shah ◽  
...  
Keyword(s):  
Life Cycle ◽  
Cathodic Protection ◽  
Life Cycle Cost ◽  
Concrete Structures ◽  
Cost Benefits ◽  
Long Term Performance ◽  
Term Performance

scholarly journals Ageing of old and modern concrete structures – Observations and research

2017 ◽  
Vol 7 (1) ◽  
pp. 57-72
Author(s):  
K. Van Breugel ◽  
T. A. Van Beek
Keyword(s):  
Financial Burden ◽  
Concrete Structures ◽  
Autogenous Shrinkage ◽  
Mix Design ◽  
Industrialized Countries ◽  
Concrete Mix Design ◽  
Inherent Feature ◽  
Long Term Performance ◽  
Term Performance

Ageing of old and modern concrete structures – Observations and researchABSTRACTAgeing is an inherent feature of nature. Yet it seems to be a rather new topic in both science and engineering. The main reason for increasing attention for ageing as a topic is the growing awareness that, particularly in industrialized countries, ageing of our assets is a financial burden for the society and affects the overall sustainability of our planet. In this contribution, the urgency and challenges of ageing of concrete structures are addressed. The complexity of ageing problems will be illustrated by looking in more detail to the evolution in concrete mix design and the consequences thereof for the long-term performance of concrete structures. Emphasis will be on ageing of concrete infrastructure and justification of research on ageing phenomena.Keywords: infrastructure; sustainability; ageing; mix design; autogenous shrinkage; codes. Envejecimiento de antiguas y modernas estructuras de concreto - Observaciones e investigacionesRESUMENEl envejecimiento es una característica inherente de la naturaleza. Sin embargo, parece ser un tema bastante nuevo en la ciencia y la ingeniería. La principal razón para aumentar la atención por el envejecimiento como tema es la creciente conciencia de que, en particular en los países industrializados, el envejecimiento de nuestros activos es una carga financiera para la sociedad y afecta la sostenibilidad global de nuestro planeta. En esta contribución se abordan la urgencia y los desafíos del envejecimiento de las estructuras de concreto. La complejidad de los problemas de envejecimiento se ilustra examinando con más detalle la evolución del diseño de la mezcla de concreto y sus consecuencias para el rendimiento a largo plazo de las estructuras de concreto. Se hace hincapié en el envejecimiento de las infraestructuras de concreto y en la justificación de la investigación sobre fenómenos de envejecimiento.Palabras clave: infraestructura; sostenibilidad; envejecimiento; mezcla de diseño; contracción autógena; códigos. Envelhecimento estruturas de betão antigos e modernos - Observações e pesquisaRESUMOO envelhecimento é uma característica inerente à natureza. No entanto, parece ser um bastante novo tópico em ciência e engenharia. A principal razão para uma maior atenção por tema envelhecimento é a consciência crescente de que, particularmente nos países industrializados, o envelhecimento dos nossos ativos é um encargo financeiro para a sociedade e afeta a sustentabilidade global do nosso planeta. Nesta contribuição a urgência e os desafios de estruturas de concreto envelhecimento são abordados. A complexidade dos problemas de envelhecimento está ilustrada em mais pormenor através da análise da evolução do desenho da mistura de betão e o seu impacto sobre o desempenho a longo prazo das estruturas de betão. A ênfase é colocada na infra-estrutura de envelhecimento do concreto e justificação da pesquisa sobre os fenómenos de envelhecimento.Palavras-chave: infra-estrutura; sustentabilidade; envelhecimento; misture projeto; retração autógena; códigos.

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