Service life of reinforced concrete seawalls suffering from chloride attack: Theoretical modelling and analysis

2020 ◽  
Vol 263 ◽  
pp. 120172 ◽  
Author(s):  
Changyi Yang ◽  
Lin Li ◽  
Jingpei Li
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Theoretical Modelling ◽  
Chloride Attack

Use of Portland Pozzolana Cement to Enhance the Service Life of Reinforced Concrete Exposed to Chloride Attack

2015 ◽  
Vol 27 (11) ◽  
pp. 04015031 ◽  
Author(s):  
Bhaskar Sangoju ◽  
Radhakrishna G. Pillai ◽  
Ravindra Gettu ◽  
B. H. Bharatkumar ◽  
Nagesh R. Iyer
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Chloride Attack ◽  
Portland Pozzolana Cement

scholarly journals Chloride Diffusion Property of Hybrid Basalt–Polypropylene Fibre-Reinforced Concrete in a Chloride–Sulphate Composite Environment under Drying–Wetting Cycles

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1138
Author(s):  
Yang Luo ◽  
Ditao Niu ◽  
Li Su
Keyword(s):  
Reinforced Concrete ◽  
Coupling Effect ◽  
Early Stage ◽  
Polypropylene Fibre ◽  
Chloride Diffusion ◽  
Fibre Reinforcement ◽  
Fibre Reinforced Concrete ◽  
Basalt Fibre ◽  
Diffusion Property ◽  
Chloride Attack

The effect of fibre reinforcement on the chloride diffusion property of concrete is controversial, and the coupling effect of sulphate erosion and drying–wetting cycles in marine environments has been neglected in previous studies. In this study, the chloride diffusion property of hybrid basalt–polypropylene fibre-reinforced concrete subjected to a combined chloride–sulphate solution under drying–wetting cycles was investigated. The effects of basalt fibre (BF), polypropylene fibre (PF), and hybrid BP–PF on the chloride diffusion property were analysed. The results indicate that the presence of sulphate inhibits the diffusion of chloride at the early stage of erosion. However, at the late stage of erosion, sulphate does not only accelerate the diffusion of chloride by causing cracking of the concrete matrix but also leads to a decrease in the alkalinity of the pore solution, which further increases the risk of corrosion of the reinforcing steel. An appropriate amount of fibre can improve the chloride attack resistance of concrete at the early stage. With the increase in erosion time, the fibre effectively prevents the formation and development of sulphate erosion microcracks, thus reducing the adverse effects of sulphate on the resistance of concrete to chloride attack. The effects of sulphate and fibre on the chloride diffusion property were also elucidated in terms of changes in corrosion products, theoretical porosity, and the fibre-matrix interface transition zone.

Physical and Chemical Deterioration of Reinforced Concrete Reefs in Tongyeong Reefs Coastal Waters, Korea

2008 ◽  
Vol 42 (3) ◽  
pp. 110-118 ◽  
Author(s):  
H. S. Kim ◽  
C. G. Kim ◽  
W. B. Na ◽  
J. Woo ◽  
J. K. Kim
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Dissolved Oxygen ◽  
Extreme Event ◽  
Chemical Properties ◽  
Chloride Concentration ◽  
Concrete Cover ◽  
Marine Habitat ◽  
Seawater Salinity ◽  
Physical And Chemical

As part of a marine habitat enhancement project, the physical and chemical deterioration of reinforced concrete reefs that were fully immersed in Tongyeong waters of Korea was investigated. For the investigation, marine environmental factors such as seawater, salinity, pH, dissolved oxygen, sea-bottom materials, and water depth of the targeted sites were surveyed from 1997 to 2001. Then, four reinforced concrete reefs from four different sites were recovered and tested by using various destructive and nondestructive methods. Based on the observations and test results, it was seen that the reinforced concrete reefs have sound physical and chemical properties, except for chloride concentration and its associated factors. However, because of the lack of dissolved oxygen in the targeted seawaters and its continuous supply, it is concluded that the originally designed service life will be achieved, and in fact the concrete reefs will have an even longer service life than expected. By considering an extreme event such as impact loading under installation and construction, a new minimum concrete cover depth of 40 mm is introduced into practice.

scholarly journals Specific feature of the restoration of operability of KPP-5 fasteners by using PRP-3.2 and PRP-3.2.1 rail pads

2018 ◽  
Vol 230 ◽  
pp. 01005
Author(s):  
Denis Fast ◽  
Natalia Bugaets ◽  
Volodymir Vitolberg ◽  
Alexandr Lichodey ◽  
Volodymyr Stefanov
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Traffic Load ◽  
Rational Use ◽  
Pressing Force ◽  
Standard Service

Areas of rational use of the track construction with reinforced concrete sleepers have been defined, however, it requires improving and the problem of intermediate rail fastenings is particularly serious here. The most common intermediate rail fasteners used in Ukrzaliznytsya are lining terminal-bolted fasteners of KB type and direct fixation boltless fastening type KPP-5. Calculations have been made for the restoration of operability of KPP-5 fasteners using PRP-3.2 repair pads with a thickness of 9 mm and PRP-3.2.1 with a thickness of 10 mm. It has been established that in the sections with the traffic load of more than 15 million ton km/km in year, restoration works should be performed after 13 years of operation. Using 10 mm thick PRP-3.2.1 rail pads will provide the necessary pressing force of the rail base against the sleeper until the expiration of the standard service life – no more than 30 years. When the traffic load is less than or equal to 15 million ton km/km in year, recovery can be performed after 22 years of operation. The use of both types of pads will ensure the reliable functioning of KPP-5 fasteners until the expiration of its service life.

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