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 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.

COMBUSTION ENERGY AND FOSSIL (NON-BIOBASED) CO2 EMISSIONS FROM RUBBER COMPOUNDS UNDER COMPLETE COMBUSTION BY BOMB CALORIMETER BASED ON ISO 20463 METHODS

2020 ◽  
pp. 000-000
Author(s):  
Masao Kunioka ◽  
Akira Saito ◽  
Mari Nakajima ◽  
Shunji Araki
Keyword(s):  
Carbon Content ◽  
Co2 Emissions ◽  
Co2 Emission ◽  
Calorific Value ◽  
Co2 Concentration ◽  
Complete Combustion ◽  
Combustion Gas ◽  
Combustion Energy ◽  
Bomb Calorimeter ◽  
Rubber Compounds

ABSTRACT Combustion energy (gross calorific value) and total CO2 emissions from 11 model rubber compounds, polyurethane, and other materials related to rubber products during a one-time complete combustion were measured sequentially using methods in accordance with ISO 20463 using a bomb calorimeter. Eleven model rubber compounds and biobased polyurethane were prepared for these measurements. The combustion energies of the model rubber compounds were found to be 27 900 to 40 700 J/g. These measured combustion energies, after subtraction of the combustion energy of carbon black (CBK), were related linearly to the carbon content of these samples without CBK. A difference in the combustion energy of rubber products and that of CBK was observed. From these results, an estimation via the calculation of the combustion energy of the rubber products was developed from the formulation of the rubber product. Total CO2 emissions could be calculated by the results of total volume and the CO2 concentration of combustion gas collected from a bomb used for the measurement of combustion energies. The total CO2 emissions of these samples were 1.83 to 3.02 g/g. The relationship between total CO2 emission from model rubber compounds and the theoretical CO2 emission calculated from the carbon content of these samples was linear. It was found that these methods had high precision. High reproducibility of the methods for such measurement was confirmed by the use of a round-robin test, which was carried out by six Japanese chemical laboratories.

scholarly journals Probabilistic Corrosion Initiation Model for Coastal Concrete Structures

2020 ◽  
Vol 1 (3) ◽  
pp. 328-344
Author(s):  
Changkyu Kim ◽  
Do-Eun Choe ◽  
Pedro Castro-Borges ◽  
Homero Castaneda
Keyword(s):  
Experimental Data ◽  
Environmental Conditions ◽  
Bayesian Model ◽  
Structural Reliability ◽  
Electrochemical Corrosion ◽  
Corrosion Process ◽  
Sensitivity Analyses ◽  
Theoretical Understanding ◽  
Rc Structures ◽  
Corrosion Initiation

Corrosion of the reinforced concrete (RC) structures has been affecting the major infrastructures in U.S. and in other continents, causing the recent several bridge collapses and incidents. While the theoretical understanding is well-established, the reliable prediction of the corrosion process in the RC structural systems has hardly been successful due to the inherent uncertainties existed in the electrochemical corrosion process and the associated material and environmental conditions. The paper proposes a computational framework to develop evidence-based probabilistic corrosion initiation models for the reinforcing steels in the RC structures, which predicts the corrosion initiation time and quantifies the inherent variances considering various acting parameters. The framework includes: probabilistic modeling with Bayesian updating based on the sets of previously generated experimental data; Bayesian model/parameter selection considering various parameters, such as material properties and environmental conditions; corrosion reliability analyses to predict the probabilities of the corrosion initiation at given time t, structural configurations, and environmental conditions; and sensitivity analyses to measure and to rank the influences of each acting parameter and its uncertainty to the probabilities of the corrosion initiation. Total of 284 sets of experimental data exposed to the coastal atmospheric environments are used for the modeling. The goal of the Bayesian model selection presented in this paper is to obtain the most accurate and unbiased model using the simplest form of expression. The developed example corrosion model is currently limited to the initiation of diffusion-induced corrosion. The model can be updated, improved, or modified upon future available sets of data. The research contributes to the decision making to improve the corrosion reliability, corrosion control, and further the structural reliability of corroding structures.

scholarly journals Evaporative Cooling Options for Building Air-Conditioning: A Comprehensive Study for Climatic Conditions of Multan (Pakistan)

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3061 ◽  
Author(s):  
Shazia Noor ◽  
Hadeed Ashraf ◽  
Muhammad Sultan ◽  
Zahid Mahmood Khan
Keyword(s):  
Thermal Comfort ◽  
Co2 Emissions ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Maximum Temperature ◽  
Human Thermal Comfort ◽  
Work Input ◽  
System Configurations

This study provides comprehensive details of evaporative cooling options for building air-conditioning (AC) in Multan (Pakistan). Standalone evaporative cooling and standalone vapor compression AC (VCAC) systems are commonly used in Pakistan. Therefore, seven AC system configurations comprising of direct evaporative cooling (DEC), indirect evaporative cooling (IEC), VCAC, and their possible combinations, are explored for the climatic conditions of Multan. The study aims to explore the optimum AC system configuration for the building AC from the viewpoints of cooling capacity, system performance, energy consumption, and CO2 emissions. A simulation model was designed in DesignBuilder and simulated using EnergyPlus in order to optimize the applicability of the proposed systems. The standalone VCAC and hybrid IEC-VCAC & IEC-DEC-VCAC system configurations could achieve the desired human thermal comfort. The standalone DEC resulted in a maximum COP of 4.5, whereas, it was 2.1 in case of the hybrid IEC-DEC-VCAC system. The hybrid IEC-DEC-VCAC system achieved maximum temperature gradient (21 °C) and relatively less CO2 emissions as compared to standalone VCAC. In addition, it provided maximum cooling capacity (184 kW for work input of 100 kW), which is 85% higher than the standalone DEC system. Furthermore, it achieved neutral to slightly cool human thermal comfort i.e., 0 to −1 predicted mean vote and 30% of predicted percentage dissatisfied. Thus, the study concludes the hybrid IEC-DEC-VCAC as an optimum configuration for building AC in Multan.

scholarly journals Effects of Climatic Conditions, Season and Environmental Factors on CO2 Concentrations in Naturally Ventilated Primary Schools in Chile

2021 ◽  
Vol 13 (8) ◽  
pp. 4139
Author(s):  
Muriel Diaz ◽  
Mario Cools ◽  
Maureen Trebilcock ◽  
Beatriz Piderit-Moreno ◽  
Shady Attia
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Primary Schools ◽  
Co2 Concentration ◽  
Building Design ◽  
Climatic Conditions ◽  
Indoor Environmental Quality ◽  
Co2 Concentrations ◽  
The Impact

Between the ages of 6 and 18, children spend between 30 and 42 h a week at school, mostly indoors, where indoor environmental quality is usually deficient and does not favor learning. The difficulty of delivering indoor air quality (IAQ) in learning facilities is related to high occupancy rates and low interaction levels with windows. In non-industrialized countries, as in the cases presented, most classrooms have no mechanical ventilation, due to energy poverty and lack of normative requirements. This fact heavily impacts the indoor air quality and students’ learning outcomes. The aim of the paper is to identify the factors that determine acceptable CO2 concentrations. Therefore, it studies air quality in free-running and naturally ventilated primary schools in Chile, aiming to identify the impact of contextual, occupant, and building design factors, using CO2 concentration as a proxy for IAQ. The monitoring of CO2, temperature, and humidity revealed that indoor air CO2 concentration is above 1400 ppm most of the time, with peaks of 5000 ppm during the day, especially in winter. The statistical analysis indicates that CO2 is dependent on climate, seasonality, and indoor temperature, while it is independent of outside temperature in heated classrooms. The odds of having acceptable concentrations of CO2 are bigger when indoor temperatures are high, and there is a need to ventilate for cooling.

scholarly journals Conventional and Alternative Sources of Thermal Energy in the Production of Cement—An Impact on CO2 Emission

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1539
Author(s):  
Karolina Wojtacha-Rychter ◽  
Piotr Kucharski ◽  
Adam Smolinski
Keyword(s):  
Co2 Emissions ◽  
Co2 Emission ◽  
Alternative Fuels ◽  
Carbon Dioxide Emission ◽  
Calorific Value ◽  
Production Costs ◽  
Partial Substitution ◽  
Research Activities ◽  
Starting Point ◽  
Clinker Production

The article evaluates the reduction of carbon dioxide emission due to the partial substitution of coal with alternative fuels in clinker manufacture. For this purpose, the calculations were performed for seventy waste-derived samples of alternative fuels with variable calorific value and variable share in the fuel mixture. Based on annual clinker production data of the Polish Cement Association and the laboratory analysis of fuels, it was estimated that the direct net CO2 emissions from fossil fuel combustion alone were 543 Mg of CO2 per hour. By contrast with the full substitution of coal with alternative fuels (including 30% of biomass), the emission ranged from 302 up to 438 Mg of CO2 per hour, depending on fuel properties. A reduction of 70% in the share of fossil fuels resulted in about a 23% decrease in net emissions. It was proved that the increased use of alternative fuels as an additive to the fuel mix is also of economic importance. It was determined that thanks to the combustion of 70% of alternative fuels of calorific value from 15 to 26 MJ/kg, the hourly financial profit gain due to avoided CO2 emission and saved 136 megatons of coal totaled an average of 9718 euros. The results confirmed that the co-incineration of waste in cement kilns can be an effective, long-term way to mitigate carbon emissions and to lower clinker production costs. This paper may constitute a starting point for future research activities and specific case studies in terms of reducing CO2 emissions.

scholarly journals Pulp and Paper Industry: Decarbonisation Technology Assessment to Reach CO2 Neutral Emissions—An Austrian Case Study

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1161
Author(s):  
Maedeh Rahnama Mobarakeh ◽  
Miguel Santos Silva ◽  
Thomas Kienberger
Keyword(s):  
Energy Consumption ◽  
Co2 Emissions ◽  
Emission Reduction ◽  
Co2 Emission ◽  
Manufacturing Industry ◽  
Paper Industry ◽  
Heat Pumps ◽  
Pulp And Paper ◽  
Low Carbon ◽  
Co2 Emission Reduction

The pulp and paper (P&P) sector is a dynamic manufacturing industry and plays an essential role in the Austrian economy. However, the sector, which consumes about 20 TWh of final energy, is responsible for 7% of Austria’s industrial CO2 emissions. This study, intending to assess the potential for improving energy efficiency and reducing emissions in the Austrian context in the P&P sector, uses a bottom-up approach model. The model is applied to analyze the energy consumption (heat and electricity) and CO2 emissions in the main processes, related to the P&P production from virgin or recycled fibers. Afterward, technological options to reduce energy consumption and fossil CO2 emissions for P&P production are investigated, and various low-carbon technologies are applied to the model. For each of the selected technologies, the potential of emission reduction and energy savings up to 2050 is estimated. Finally, a series of low-carbon technology-based scenarios are developed and evaluated. These scenarios’ content is based on the improvement potential associated with the various processes of different paper grades. The results reveal that the investigated technologies applied in the production process (chemical pulping and paper drying) have a minor impact on CO2 emission reduction (maximum 10% due to applying an impulse dryer). In contrast, steam supply electrification, by replacing fossil fuel boilers with direct heat supply (such as commercial electric boilers or heat pumps), enables reducing emissions by up to 75%. This means that the goal of 100% CO2 emission reduction by 2050 cannot be reached with one method alone. Consequently, a combination of technologies, particularly with the electrification of the steam supply, along with the use of carbon-free electricity generated by renewable energy, appears to be essential.

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