scholarly journals Improving Performance And Durability Of Concrete

2021 ◽  
Author(s):  
Mohammad R. Nazeran
Keyword(s):  
Service Life ◽  
Porous Material ◽  
Concrete Structure ◽  
High Quality ◽  
Significant Deterioration ◽  
Design Service Life ◽  
Chloride Attack ◽  
New Material ◽  
Concrete Materials ◽  
Maintenance Problem

Concrete is a porous material with different size of pores and cracks. Even the high quality concrete is a porous material which can pass the water through its cement paste. Porosity of the concrete can affect the natural performance of the concrete structure. Usually the water that comes from the environment contains the soluable contaminates which may initiate the reaction with the concrete materials and reduce the serviceability and design service life of the concrete. Durable structures to withstand significant deterioration can help to reduce the maintenance problem and conserves energy, money, materials and resources. The purpose of this research is to determine the major durability problem of concrete structure. The effects of critical environment deterioration such as sulfate and chloride attack was studied. Also the use of recycle and new material that might offset the destructive effects of environment attack to improve the durability or reduce the permeability was investigated.

scholarly journals Improving Performance And Durability Of Concrete

2021 ◽  
Author(s):  
Mohammad R. Nazeran
Keyword(s):  
Service Life ◽  
Porous Material ◽  
Concrete Structure ◽  
High Quality ◽  
Significant Deterioration ◽  
Design Service Life ◽  
Chloride Attack ◽  
New Material ◽  
Concrete Materials ◽  
Maintenance Problem

Concrete is a porous material with different size of pores and cracks. Even the high quality concrete is a porous material which can pass the water through its cement paste. Porosity of the concrete can affect the natural performance of the concrete structure. Usually the water that comes from the environment contains the soluable contaminates which may initiate the reaction with the concrete materials and reduce the serviceability and design service life of the concrete. Durable structures to withstand significant deterioration can help to reduce the maintenance problem and conserves energy, money, materials and resources. The purpose of this research is to determine the major durability problem of concrete structure. The effects of critical environment deterioration such as sulfate and chloride attack was studied. Also the use of recycle and new material that might offset the destructive effects of environment attack to improve the durability or reduce the permeability was investigated.

A Service Life Prediction for Waste Disposal Facility Concrete Exposed to Chloride Attack

2012 ◽  
Vol 486 ◽  
pp. 284-288
Author(s):  
Do Gyeum Kim ◽  
Hae Ryong Jung ◽  
Ki Jung Kwon ◽  
Jang Hwa Lee ◽  
Ki Beom Kim
Keyword(s):  
Service Life ◽  
Waste Disposal ◽  
Concrete Structure ◽  
Life Prediction ◽  
Service Life Prediction ◽  
Freezing And Thawing ◽  
Disposal Facility ◽  
Life Evaluation ◽  
Chloride Attack

The concrete life was shown very differently according to the conditions surrounding the structure. Because the silo concrete structure (waste disposal facility) is geomorphologically located to underground-130m below at coast, the chloride injury rather than freezing and thawing as the more important factor for the service life evaluation. In this study, the service life of silo concrete was evaluated based on the results of chloride attack

Production of High-Performance Composite Concrete Segment and Experimental Investigation of Materials

2010 ◽  
Vol 168-170 ◽  
pp. 1042-1045
Author(s):  
Ying Li Gao ◽  
Bao Guo Ma
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
High Performance ◽  
Concrete Cover ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Volume Deformation ◽  
Volume Stability ◽  
High Performance Composite ◽  
Structure Layer

Tunnel lining concrete segment is the most critical and important structural member of shield tunneling. This investigation designed and produced high-performance composite concrete segment (HCCS). Some key indexes that affect the properties of segment were tested, such as impermeability, volume stability, mechanical property, etc. The results indicated that the impermeability of HCCS concrete cover was excellent and the chloride diffusion coefficient decreased one order of magnitude compared to that of the ordinary segment concrete cover, while the service-life of HCCS increased more than ten-fold. The volume stability of HCCS concrete cover and concrete structure layer were good and the better compatibility in the volume deformation of the whole structure was shown. Furthermore, the mechanical properties of concrete cover and concrete structure layer met the project requirement perfectly, ensuring the higher durability and longer service-life of HCCS effectively.

scholarly journals Sensitivity of Service Life Extension and CO2 Emission due to Repairs by Silane Treatment Applied on Concrete Structures under Time-Dependent Chloride Attack

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Aruz Petcherdchoo
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Treatment Strategies ◽  
Time Dependent ◽  
Life Extension ◽  
Silane Treatment ◽  
Application Time ◽  
Free Service ◽  
Chloride Attack ◽  
Service Life Extension

This paper presents sensitivity of service life extension and CO2 emission due to silane (alkyltriethoxysilane) treatment on concrete structures under time-dependent chloride attack. The service life is predicted by the Crank–Nicolson-based finite difference approach for avoiding the complexity in solving Fick’s second law. The complexity occurs due to time-dependent chloride attack and nonconstant diffusion coefficient of concrete with silane treatment. At the application time of silane treatment, the cumulative CO2 emission is assessed. The effectiveness of silane treatment is defined as the ratio of the service life extension to the cumulative CO2 emission assessed within the corrosion-free service life. The service life extension is defined as the difference between corrosion-free service life of concrete structures without and with time-based application of silane treatment. From the study, the diffusion of chlorides in concrete with silane treatment is found to be retarded. In comparison, the strategy without deterioration of silanes during effective duration is more suitable for service life extension but less effective than that with deterioration. In the sensitivity analysis, there are up to eight parameters to be determined. The service life of concrete structures without silane treatment is most sensitive to the water-to-cement ratio and the threshold depth of concrete structures. Considering only five parameters in silane treatment strategies, the service life is most sensitive to the first application time of silane treatment. The cumulative CO2 emission is most sensitive to either the first application time of silane treatment or the amount of CO2 emission per application.

scholarly journals The Composition of Fatty Acids in Ostrich Meat Influenced by the Type of Packaging and Refrigerated Storage

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4128
Author(s):  
Olaf K. Horbańczuk ◽  
Małgorzata Moczkowska ◽  
Joanna Marchewka ◽  
Atanas G. Atanasov ◽  
Marcin A. Kurek
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Storage Time ◽  
Modified Atmosphere Packaging ◽  
Vacuum Packaging ◽  
Modified Atmosphere ◽  
Refrigerated Storage ◽  
High Quality ◽  
Significant Deterioration ◽  
And Storage

Ostrich meat is a high-quality dietetic product, however, it is very sensitive to deterioration during storage. The aim of this study was to assess the effect of packaging systems on the fatty acid (FA) profiles in ostrich meat during refrigerated storage. The systems were: Vacuum packaging (VP) and modified atmosphere packaging (MAP) in two combinations of gases: MAP1 (40% O2/40% CO2/20% N2) and MAP2 (60% O2/30% CO2/10% N2). Samples were taken from the M. ilifibularis (IF) muscles of eight ostriches in each treatment group. The packs were stored in a refrigerator at 2 °C and analyzed at 0, 4, 8, 12 and 16 days. The packaging conditions and storage time had an impact on the concentration of bioactive compounds such as polyunsaturated fatty acids (PUFA), including n-3 such as C18:3, C20:5 (EPA) and C22:6 (DHA). The least changes in composition of n-3 and the sum of PUFA were recorded in ostrich meat packaged in vacuum, followed by that packaged using MAP1 and MAP2. The sum of n-6 PUFAs decreased significantly by 2.1% for MAP2, and only by 0.7% for vacuum packaging as the experiment progressed. A significant deterioration of these compounds was observed in all package systems, especially from day 12 until day 16 of storage.

Service Life Extension and CO2 Emission due to Silane Treatment on Chloride-Exposed Concrete Structures

2017 ◽  
Vol 728 ◽  
pp. 384-389
Author(s):  
Aruz Petcherdchoo ◽  
Chotima Ongsopapong
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Treatment Strategies ◽  
Life Extension ◽  
Chloride Diffusion ◽  
Silane Treatment ◽  
Free Service ◽  
Before And After ◽  
Chloride Attack ◽  
Service Life Extension

This study presents assessment of the environmental impact in terms of the CO2 due to silane treatment for extending corrosion-free service life of concrete structures under chloride attack. To achieve this, there are two issues to be addressed; prediction of corrosion-free service life extension, and assessment of the amount of CO2 emission. In predicting the corrosion-free service life extension, the behaviors of chloride diffusion before and after time-based silane treatment are considered. Then, the cumulative CO2 due to silane treatment is accordingly calculated. The ratio of the corrosion-free service life extension to the cumulative CO2 is defined as the effectiveness of silane treatment, and used to compare different silane treatment strategies.

Analysis on Concrete Neutralization and Life Evaluation of Reinforced Concrete Chimney

2013 ◽  
Vol 671-674 ◽  
pp. 1672-1675
Author(s):  
Yan Hui Li ◽  
Yang Yang Zhang ◽  
Jing Cun Wei ◽  
Yun Feng Wu
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Structure ◽  
Concrete Cover ◽  
Initiation Time ◽  
Reinforcement Corrosion ◽  
Single Factor ◽  
Routine Examination ◽  
Life Evaluation ◽  
Reinforced Concrete Chimney

Through calculation and analysis on routine examination and neutralization of reinforced concrete chimney, the service life of concrete structure was evaluated only considering neutralization of concrete single factor. The results show that the neutralization of the reinforced concrete chimney was serious than that of other similar projects. The initiation time of reinforcement corrosion were 19.3a, cracking time of concrete cover were 27.35a.

Service Life of Concrete Structures

2020 ◽  
Vol 309 ◽  
pp. 267-271
Author(s):  
Milan Holicky ◽  
Jiří Kolísko
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
Limit State ◽  
Concrete Structures ◽  
Technical Specification ◽  
Working Life ◽  
Degradation Process ◽  
International Standards ◽  
Limit States ◽  
Existing Structures

The concept of service life of structures is included in international standards ISO (under the term Design Working Life), in the European document EN 1990 (Design Service Life) and in the upcoming document CEN for assessment of existing structures - Technical Specification TS (Remaining Working Life). The mentioned documents contain mainly material-independent provisions for the design and assessment of all types of structures and for any category of actions. The submitted paper includes the definition of service life (performance time) tser, which is extended for any concrete structure, considering the resistance of a structure R(t) and the effect of action S(t). Both the aggregate variables R(t) and S(t) are usually random variables significantly dependent on time t. Due to the random variability of the variables R(t) and S(t), the service life tser, needs to be related to the probability that the performance of the structure is weakened or completely eliminated. Basically, serviceability limit states (SLS) and ultimate limit states (ULS) should be considered. In the case of concrete structures another limit state corresponding to the beginning of a specific degradation process (corrosion of reinforcement), denoted tinit, may be important. In specific cases of buildings and bridges a functional (moral) service life may be taken into account. The paper includes also a practical example of assessing the remaining working life of a concrete structure.

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