scholarly journals Carbonation-Induced Corrosion Initiation Probability of Rebars in Concrete With/Without Finishing Materials

2018 ◽  
Vol 10 (10) ◽  
pp. 3814 ◽  
Author(s):  
Hyung-Min Lee ◽  
Han-Seung Lee ◽  
Sang-ho Min ◽  
Seungmin Lim ◽  
Jitendra Singh
Keyword(s):  
Field Survey ◽  
Probability Model ◽  
Concrete Cover ◽  
Accelerated Carbonation ◽  
Physical Barrier ◽  
Carbonation Depth ◽  
Rc Structures ◽  
Corrosion Initiation ◽  
Concrete Quality

The carbonation of concrete is the prime deterioration factor in reinforced concrete (RC) structures. During carbonation, the atmospheric CO2 penetrates the concrete and lowers its alkalinity. The problem in predicting carbonation is difficult to address, and a reliable probabilistic carbonation assessment is required to consider different variables such as the concrete quality, the chemistry of the reinforcing steel, and the quality of finishing materials. In the present study, we have used different finishing materials on concrete to minimize the effects of carbonation with a field survey and accelerated conditions. In one experiment, the measurement of the thickness of the concrete cover and the application of the finishing materials were done on-site, whereas, in the other experiment, these were done under accelerated conditions. The carbonation depth and the coefficient of silk wallpaper (SWP) were reduced by half in an accelerated 5% CO2 experiment compared to the plain ordinary Portland cement (OPC), owing to the external physical barrier that reduces the penetration of CO2 through the pores of the concrete. We found that carbonation did not reach the embedded rebar even after 100 years when SWP finishing material was used. The probability model predicted that 51 years would be required for OPC and water paint (WP) to reach a 30% onset of corrosion initiation through accelerated carbonation, while SWP would require 200 years.

Variation of Carbonation Coefficient of Pumping Concrete with Moist-Curing Time at early Ages and Fly-Ash Content

2011 ◽  
Vol 287-290 ◽  
pp. 899-905
Author(s):  
Qing Ye ◽  
Zhi Wei Song ◽  
Guo Rong Yu
Keyword(s):  
Fly Ash ◽  
Concrete Cover ◽  
Ash Content ◽  
Curing Time ◽  
Accelerated Carbonation ◽  
Carbonation Depth ◽  
Carbonation Resistance

Based on accelerated carbonation test, the variation of carbonation resistance of pumping concrete (C40 grade) with moist-curing time at early ages and fly-ash content was studied. Results indicate that the carbonation coefficient and the accelerated carbonation depth of the concrete increased obviously with a reduction in the moist-curing time at early ages and with an increase in the fly-ash content. For example, in conditions of curing schedules with 28, 7, 3, 2 and 1 d moist-curing at 20 0C with above 95% RH at early ages and then 0, 21, 25, 26 and 27 d air curing at 20 0C with 60% RH, respectively, carbonation coefficients of the concrete incorporated with 30% fly-ash were 2.04, 2.49, 3.16, 3.86 and 5.42 mm/a0.5 respectively, and thus it can be seen that the calculated times when concrete cover (25 mm) was completely carbonated naturally in now atmosphere (0.04% CO2) were 164, 104, 66, 44 and 21 years respectively. The results suggest that for the carbonation resistance of the C40 concrete incorporated with up to 30% fly-ash, the moist-curing time of 7 days at early ages should be necessary.

Influence of Early Age Wet Curing Time, Clinker and CaO Content on the Carbonation Resistance of C40 Ordinary Concrete

2011 ◽  
Vol 311-313 ◽  
pp. 1894-1900 ◽  
Author(s):  
Qing Ye
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Concrete Cover ◽  
Early Age ◽  
Curing Time ◽  
Accelerated Carbonation ◽  
Carbonation Depth ◽  
Ordinary Concrete ◽  
Carbonation Resistance

Based on accelerated carbonation test, the variation of the carbonation resistance of ordinary concrete (C40 grade) with early age wet curing time, clinker and CaO content was studied. Results indicate that the carbonation coefficient and the accelerated carbonation depth of the concrete increased obviously with a reduction in the wet curing time at early ages, the clinker or CaO content in binder and the compressive strength at 28 d age. For example, in conditions of curing schedules with 28, 7, 3, 2 and 1 d wet curing at 20 °C with above 95% RH at early ages and then 0, 21, 25, 26 and 27 d air curing at 20 °C with 60% RH, respectively, carbonation coefficients of the concrete incorporated with 15% fly-ash and 25% slag were 1.83, 2.71, 3.61, 4.67 and 5.50 mm/a0.5 respectively, and thus it can be seen that the calculated times when concrete cover (25 mm) was completely carbonated naturally in now atmosphere (0.04% CO2) were 191, 104, 52, 31 and 20 years respectively. It is possible to predict the potential carbonation coefficient of the concrete from its clinker or CaO content in binder and from its compressive strength at 28 d age in conditions of the certain wet curing time at early ages.

Reliability-Based Assessment of the Effect of Climatic Conditions and CO2 Emissions on the Corrosion of RC Structures Subjected to Carbonation

2012 ◽  
Vol 503-504 ◽  
pp. 780-784 ◽  
Author(s):  
Jun Li Liu ◽  
Zhi Fang
Keyword(s):  
Co2 Emissions ◽  
Co2 Emission ◽  
Structural Reliability ◽  
Concrete Structures ◽  
Co2 Concentration ◽  
Climatic Conditions ◽  
Emission Scenarios ◽  
Carbonation Depth ◽  
Rc Structures ◽  
Corrosion Initiation

carbonation rate of concrete structures are influenced by CO2 emissions and climate conditions. Carbonation depth prediction model was proposed and CO2 emission scenarios influence on concrete structures' carbonation damage was studied. As there are significant uncertainty and variability of CO2 emissions, deterioration mechanisms, material properties, dimensions and environments, the time-dependent structural reliability analysis was employed to predict the probability of corrosion initiation from 2000 to 2100, considering several IPCC future atmospheric CO2 emission scenarios. Results show:(1)carbonation depth in A1F1 and A1B scenarios is 36% higher than that invariant CO2 concentration, and A1B scenarios is 21%; (2)The corrosion initiation probability of RC structures in A1F1 and A1B scenarios are 84% and 67% higher than that invariant CO2 concentration , respectively.

scholarly journals Modelling of Corrosion-Induced Concrete Cover Cracking Due to Chloride Attacking

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1440
Author(s):  
Pei-Yuan Lun ◽  
Xiao-Gang Zhang ◽  
Ce Jiang ◽  
Yi-Fei Ma ◽  
Lei Fu
Keyword(s):  
Service Life ◽  
Corrosion Current ◽  
Practical Experience ◽  
Concrete Cover ◽  
Premature Failure ◽  
Rc Structures ◽  
Structural Capacity ◽  
Cover Cracking ◽  
Deterioration Process ◽  
Cracking Process

The premature failure of reinforced concrete (RC) structures is significantly affected by chloride-induced corrosion of reinforcing steel. Although researchers have achieved many outstanding results in the structural capacity of RC structures in the past few decades, the topic of service life has gradually attracted researchers’ attention. In this work, based on the stress intensity, two models are developed to predict the threshold expansive pressure, corrosion rate and cover cracking time of the corrosion-induced cracking process for RC structures. Specifically, in the proposed models, both the influence of initial defects and modified corrosion current density are taken into account. The results given by these models are in a good agreement with practical experience and laboratory studies, and the influence of each parameter on cover cracking is analyzed. In addition, considering the uncertainty existing in the deterioration process of RC structures, a methodology based on the third-moment method in regard to the stochastic process is proposed, which is able to evaluate the cracking risk of RC structures quantitatively and predict their service life. This method provides a good means to solve relevant problems and can prolong the service life of concrete infrastructures subjected to corrosion by applying timely inspection and repairs.

scholarly journals Reinforced Concrete Bridge Deck Model Considering Delayed Exposure to Chlorides

2019 ◽  
Author(s):  
Petr Konečný ◽  
Petr Lehner ◽  
David Pustka
Keyword(s):  
Reinforced Concrete ◽  
Bridge Deck ◽  
Concrete Bridge ◽  
Reinforced Concrete Bridge ◽  
Corrosion Initiation ◽  
Chloride Induced Corrosion ◽  
Concrete Quality ◽  
Concrete Type ◽  
Concrete Bridge Deck ◽  
Delayed Exposure

The paper is focused on the model of the effect of delayed chloride exposure on the chloride induced corrosion initiation on ideal reinforced concrete bridge. The Finite Element-based numerical model is applied. The effect of concrete quality is expressed in the form of time dependent diffusion coefficient in order to evaluate the effect of concrete type as well as the effect of aging. The influence of extended chloride exposure on the corrosion initiation is introduced.

scholarly journals A field survey on the indoor environmental quality of the UK primary school classroom

2016 ◽  
Vol 11 (10) ◽  
pp. 492-496 ◽  
Author(s):  
Yufan Zhang ◽  
Peter Barrett ◽  
Fay Davies ◽  
Lucinda Barrett
Keyword(s):  
Primary School ◽  
Environmental Quality ◽  
Field Survey ◽  
Indoor Environmental Quality ◽  
School Classroom ◽  
The Uk

scholarly journals PERAN RUANG TERBUKA HIJAU DALAM PERENCANAAN KOTA SEBAGAI POTENSI PEMBENTUK SMART CITY

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Hanny Maria Caesarina ◽  
Nahdi Saubari
Keyword(s):  
Urban Planning ◽  
Environmental Quality ◽  
Smart City ◽  
Green Space ◽  
Field Survey ◽  
Supporting Element ◽  
Internet Network

Ruang terbuka hijau telah dikenal memiliki peranan yang penting dalam meningkatkan kualitas lingkungan perkotaan. Ruang terbuka hijau dalam perencanaan kota kerap dianggap sebagai elemen pendukung terwujudnya smart city. Penelitian ini bertujuan untuk menemukan seberapa jauh peran ruang terbuka hijau lewat penyediaan wifi corner dalam perencanaan kota menuju konsep smart city. Metode yang digunakan adalah deskriptif kualitatif berdasarkan observasi, survey lapangan dan serangkaian wawancara. Studi kasus yang diambil dalam penelitian ini adalah dua kota di Kalimantan Selatan, yaitu Banjarmasin dan Banjarbaru yang telah memiliki konsep smart city. Hasil penelitian menunjukkan bahwa ruang terbuka hijau dalam perencanaan kota memiliki potensi yang kuat sebagai elemen pembentuk smart city. Apabila ruang terbuka hijau suatu kota telah direncanakan dengan baik dari berbagai segi fasilitas dan terkoneksi dengan jaringan internet yang berkualitas, maka dengan sendirinya konsep smart city akan lebih mudah dicapai. Kata kunci: perencanaan kota, ruang terbuka hijau, smart city, wifi corner. Green space has an important role in enhancing environmental quality of a city. Green space often considered as a supporting element for the concept of smart city. This research intended to acknowledge the role of green space through the installation of wifi corner in urban planning towards smart city. The methods that has been used was descriptive qualitative through observation, field survey and interviews. The case study in this research were Banjarmasin and Banjarbaru which already has the smart city concepts. The result shows that green space in urban planning is a potential element towards smart city. A well good planned green space with all the facilities that connected to a good internet network in a city might help forming the concept of smart city. Keywords: green space, smart city, urban planning, wifi corner.

scholarly journals Economic Impact to Quality of Life of Agropolitan Participants in Malaysia

2018 ◽  
Vol 3 (8) ◽  
pp. 57
Author(s):  
Yusof Ahmad ◽  
Hamid Saad ◽  
Eusoff @Yendo Afgani ◽  
Naeemah Yusof
Keyword(s):  
Quality Of Life ◽  
Developing Countries ◽  
Economic Impact ◽  
East Coast ◽  
Field Survey ◽  
Economic Region ◽  
Absolute Poverty ◽  
Government Program ◽  
Keywords Quality Of Life

Quality of Life (QOL) issues have increasingly been the area of attention in cities of newly developing countries including Malaysia. To improve QOL for people of absolute poverty in Malaysia, the Malaysian government have carried out a program known as Agropolitan in the East Coast Economic Region. The three Agropolitan project locations selected for this study are Batu 8 Lepar and Runchang in Pekan, Pahang and Gua Musang in Kelantan. This study carried out a field survey on 254 samples to investigate their experiences throughout the project. This study found that Agropolitan project had remarkably improved the QOL of participants Keywords: quality of life; agropolitan; absolute poverty; government program  https://doi.org/10.21834/jabs.v3i8.278

scholarly journals Improvement in physical river habitat quality in response to river restoration measures

Geografie ◽  
2016 ◽  
Vol 121 (1) ◽  
pp. 54-78
Author(s):  
Kateřina Kujanová ◽  
Milada Matoušková
Keyword(s):  
Habitat Quality ◽  
River Restoration ◽  
Field Survey ◽  
Reference Conditions ◽  
Ecological Status ◽  
River Habitat ◽  
Restoration Measures ◽  
Hydromorphological Quality

The main goal of this paper is to verify the hypothesis that application of appropriate restoration measures can lead to an improvement in river habitat quality and to achieve good hydromorphological conditions within the ecological status under the Water Framework Directive 2000/60/ES. The study includes an analysis of river network modifications founded on comparing historical and present-day maps, a determination of regional hydromorphological reference conditions based on a field survey and measurements, an assessment of hydromorphological quality of the studied water body and a proposal of appropriate restoration measures. The effects on improvement in hydromorphological status were predicted on the basis of a simulation of hydromorphological conditions after the application of proposed restoration measures. Overall, at least a good hydromorphological status would be achieved. The study proved that it is essential to carry out a hydromorphological survey including a determination of reference conditions as it provides some outputs necessary for a proposal and application of efficient restoration.

The directorial conception on operetta Silvia by Emmerich Kálmán

2021 ◽  
Vol 13 (62) (SI) ◽  
pp. 25-36
Author(s):  
Mădălina BOURCEANU
Keyword(s):  
First Line ◽  
Concrete Quality ◽  
The Way

With a well-developed dramaturgy, "Silvia" surprises by the way in which the meticulous musical characterizations of the characters were made, offering the protagonists distinct personalities. The most popular moments that place the opera in the first line of success of Emmerich Kálmán's works, reflect very engaging rhythms. The directorial conception pleads precisely for this “essence” of operetta, of the genre show, alert, frothy, built of overturns, glasses of champagne and fine humor. The director's conception must include the appreciation of style and the visual side. The directorial conception and the artistic manifestation must achieve an aesthetic fulfilment and be legitimized in the staging of the show by the rightness of the concrete quality of the actors / images relationship

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