Description of exposure to chloride of marine concrete strutures

1997 ◽  
Author(s):  
Keyword(s):  
Marine Concrete

scholarly journals Experimental Study and Simulation Calculation of the Chloride Resistance of Concrete under Multiple Factors

2021 ◽  
Vol 11 (12) ◽  
pp. 5322
Author(s):  
Yang Ding ◽  
Tong-Lin Yang ◽  
Hui Liu ◽  
Zhen Han ◽  
Shuang-Xi Zhou ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Penetration Depth ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Chloride Ions ◽  
Finite Element Software ◽  
Chloride Resistance ◽  
Simulation Calculation ◽  
Marine Concrete ◽  
Resistance Performance

Cement is widely used in marine concrete, and its resistance to chloride ion corrosion has been widely considered. In this paper, based on a laboratory test, the influence of different hydrostatic pressures, coarse aggregate contents and w/c ratios on the chloride resistance performance is analyzed. Based on COMSOL finite element software, a two-dimensional cementitious materials model is established, and the simulation results are compared with the experimental results. The results show that the penetration depth of chloride ions in cement increases with the increase of the w/c ratio. Under the hydrostatic pressure of 0 MPa, when the w/c ratio is 0.35, the penetration depth of chloride ions is 7.4 mm, and the simulation result is 8.0 mm. When the w/c ratio is 0.45, the penetration depth of chloride ions is 9.3 mm, and the simulation result is 9.9 mm. When the w/c ratio is 0.55, the penetration depth of chloride ions is 12.9 mm, and the simulation result is 12.1 mm. Under different hydrostatic pressures, the penetration depth of chloride ions obviously changes, and with the increase in hydrostatic pressure, the penetration depth of chloride ions deepens. Under the w/c ratio of 0.35, when the hydrostatic pressure is 0.5 MPa, the penetration depth of chloride ions is 11.3 mm, and the simulation result is 12.1 mm. When the hydrostatic pressure is 1.0 MPa, the penetration depth of chloride ions is 16.2 mm, and the simulation result is 17.5 mm.

Test and Study on Green High-Performance Marine Concrete Containing Ultra-Fine Limestone Powder

2013 ◽  
Vol 368-370 ◽  
pp. 1112-1117
Author(s):  
Jin Hui Li ◽  
Liu Qing Tu ◽  
Ke Xin Liu ◽  
Yun Pang Jiao ◽  
Ming Qing Qin
Keyword(s):  
Fly Ash ◽  
High Performance ◽  
Mechanical Performance ◽  
Chloride Ion ◽  
Limestone Powder ◽  
Ion Permeability ◽  
High Quality ◽  
Cracking Resistance ◽  
Slag Powder ◽  
Marine Concrete

In order to solve the environment pollution of limestone powder during production of limestone manufactured sand and gravel and problem of lack of high quality fly ash or slag powder in ocean engineering, ultra-fine limestone powder was selected for preparation of green high-performance marine concrete containing fly ash and limestone powder and that containing slag powder and limestone powder for tests on workability, mechanical performance, thermal performance, shrinkage, and resistance to cracking and chloride ion permeability. And comparison was made between such green high-performance concrete and conventional marine concrete containing fly ash and slag powder. Moreover, the mechanism of green high-performance marine concrete was preliminary studied. Results showed that ultra-fine limestone powder with average particle size around 10μm had significant water reducing function and could improve early strength of concrete. C50 high-performance marine concrete prepared with 30% fly ash and 20% limestone powder or with 30% slag powder and 30% limestone powder required water less than 130kg/m3, and showed excellent workability with 28d compressive strength above 60MPa, 56d dry shrinkage rate below 300με, cracking resistance of grade V, 56d chloride ion diffusion coefficient not exceeding 2.5×10-12m2/s. Mechanical performance and resistance to chloride ion permeability of limestone powder marine concrete were quite equivalent to those of conventional marine concrete. But it had better workability, volume stability and cracking resistance. Moreover, it can serve as a solution to the lack of high quality fly ash and slag powder.

scholarly journals Deterioration of marine concrete exposed to wetting-drying action

2021 ◽  
Vol 278 ◽  
pp. 123383 ◽  
Author(s):  
Matthew Zhi Yeon Ting ◽  
Kwong Soon Wong ◽  
Muhammad Ekhlasur Rahman ◽  
Selowara Joo Meheron
Keyword(s):  
Marine Concrete

scholarly journals Design and Evaluation of an Ultrahigh-Strength Coral Aggregate Concrete for Maritime and Reef Engineering

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5871
Author(s):  
Jinming Liu ◽  
Boyu Ju ◽  
Wei Xie ◽  
Huang Yu ◽  
Haiying Xiao ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Autogenous Shrinkage ◽  
X Ray Diffraction ◽  
Early Hydration ◽  
X Ray ◽  
Ultrahigh Strength ◽  
Marine Concrete ◽  
Marine Engineering ◽  
Reactive Powder ◽  
Economical Alternative

In this paper, an ultrahigh-strength marine concrete containing coral aggregates is developed. Concrete fabricated from marine sources is considered an effective and economical alternative for marine engineering and the construction of remote islands. To protect sea coral ecosystems, the coral aggregates used for construction are only efflorescent coral debris. To achieve the expected mechanical performance from the studied concrete, an optimal mixture design is conducted to determine the optimal proportions of components, in order to optimize the compressive strength. The mechanical properties and the autogenous shrinkage, as well as the heat flow of early hydration reactions, are measured. The hydration products fill up the pores of coral aggregates, endowing our concrete with flowability and self-compacting ability. The phases in the marine concrete are identified via X-ray diffraction analysis. The 28-day compressive and flexural strength of the developed marine concrete achieve 116.76 MPa and 18.24 MPa, respectively. On account of the lower cement content and the internal curing provided by coral aggregates, the volume change resulting from autogenous shrinkage is only 63.11% of that of ordinary reactive powder concrete.

A New Moisture Keeping Method for Marine Concrete Curing

2011 ◽  
Vol 90-93 ◽  
pp. 1195-1199
Author(s):  
Bao Lin Guo ◽  
Xiang Ming Kong ◽  
Yu Han
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Dead Weight ◽  
Cover Concrete ◽  
Concrete Quality ◽  
Curing Methods ◽  
Marine Concrete ◽  
Long Term Performance ◽  
Term Performance ◽  
Distinguishing Features

Cover concrete quality is very important for marine structures, which determines the beginning time of reinforcement corrosion and the life of the structure. The very early age continuous moisture keeping is essential for cover concrete properties develop; otherwise the long-term performance will be reduced heavily. There are many moisture keeping curing methods, but the drawbacks of traditional curing methods make them confined to use in marine environment concrete structures. A kind of moisture keeping membrane which can absorb and hold 100～5000 times of dead-weight water, and impede water evaporating outside with polyethylene film. The results of mercury intrusion porosimetry test and scanning electron microscope show that the new curing product can improve the concrete density decrease the connection degree of pores and the quantity of harmful pores content. Compared with other product on sales, the wet-keeping time can be adjusted and can be used repeatedly and continuously are the distinguishing features, which make it popular in some marine projects.

Stress-Strain Properties of Engineered Cementitious Composites (ECC) Exposed to Sulfate Dry-Wet Cycle

2020 ◽  
Vol 858 ◽  
pp. 182-187
Author(s):  
Yu Dong Han ◽  
Zhen Bo Wang ◽  
Zi Jie Hong ◽  
Jian Ping Zuo ◽  
Chang Liu ◽  
...  
Keyword(s):  
High Performance ◽  
Strain Softening ◽  
High Performance Concrete ◽  
Cementitious Composites ◽  
Ultra High Performance Concrete ◽  
Stress Strain ◽  
Engineered Cementitious Composites ◽  
Marine Concrete ◽  
New Generation ◽  
Satisfactory Prediction

The brittleness and easiness to crack expose marine concrete to serious durability issues. Engineered Cementitious Composites (ECC), as a new generation of ultra high performance concrete, is expected to overcome the strain-softening properties of traditional concrete and realize function of crack-width control. In this paper, the sulfate erosion of ECC under drying-wetting cycles was modelled in laboratory test. And the compression test on cylinders after exposure to different erosion cycles was implemented to obtain the stress-strain properties. The results disclose that sulfate erosion imposes significant influence on both the nonlinear ascending and descending portions of the stress-strain properties of ECC. As the erosion period extended, ECC strength undergoes an obvious increase. And the descending section of the eroded ECC shows a significant stress drop, which is quite different from that before erosion. Additionally, a simple analytical model was proposed to provide satisfactory prediction of the stress-strain properties of ECC exposed to sulfate erosion.

Synthesis of CaFeAl layered double hydroxides 2D nanosheets and the adsorption behaviour of chloride in simulated marine concrete

2020 ◽  
Vol 114 ◽  
pp. 103817
Author(s):  
Lei Yang ◽  
Mingxu Chen ◽  
Zeyu Lu ◽  
Yongbo Huang ◽  
Jiaao Wang ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Adsorption Behaviour ◽  
Marine Concrete ◽  
Double Hydroxides ◽  
2D Nanosheets
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