Ultrahigh Performance Concrete: A Potential Material for Sustainable Marine Construction in View of the Service Life

2013 ◽  
Vol 438-439 ◽  
pp. 108-112 ◽  
Author(s):  
Chun Ping Gu ◽  
Wei Sun ◽  
Li Ping Guo ◽  
Qian Nan Wang
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Diffusion ◽  
Sustainable Construction ◽  
Chloride Diffusion Coefficient ◽  
Normal Concrete ◽  
Superior Mechanical Properties ◽  
Chloride Profiles

Ultrahigh performance concretes (UHPC) are promising materials for the next generation infrastructures due to their superior mechanical properties and durability. In this paper, comparison studies were conducted to show the potential of UHPC for sustainable constructions in chloride environments in view of service life. For reinforced concrete, the service life was calculated with analytical solution of Ficks second law on diffusion. And for reinforced concrete with nonlinear initial chloride profiles and depth-dependent chloride diffusion coefficient, a numerical method based on the Crank-Nicholson numerical scheme was adopted to predict the service life. The results show that the reinforced concrete structures constructed and repaired with UHPC have much longer service life than that of normal concrete (NC) and high performance concrete (HPC). It hence needs less cost for maintenance and reconstruction, which fulfills the requirements of sustainable construction.

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 Investigation on Durability Performance in Early Aged High-Performance Concrete Containing GGBFS and FA

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Seung-Yup Jang ◽  
Subbiah Karthick ◽  
Seung-Jun Kwon
Keyword(s):  
Diffusion Coefficient ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Corrosion ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Structural Safety ◽  
Concrete Durability ◽  
Chloride Diffusion Coefficient ◽  
Rc Structures

The significance of concrete durability increases since RC (Reinforced Concrete) structures undergo degradation due to aggressive environmental conditions, which affects structural safety and serviceability. Steel corrosion is the major cause for the unexpected failure of RC structures. The main cause for the corrosion initiation is the ingress of chloride ions prevailing in the environment. Hence quantitative evaluation of chloride diffusion becomes very important to obtain a chloride diffusion coefficient and resistance to chloride ion intrusion. In the present investigation, 15 mix proportions with 3 water-to-binder ratios (0.37, 0.42, and 0.47) and 3 replacement ratios (0, 30, and 50%) were prepared for HPC (high-performance concrete) with fly-ash and ground granulated blast furnace slag. Chloride diffusion coefficient was measured under nonstationary condition. In order to evaluate the microstructure characteristics, porosity through MIP was also measured. The results of compressive strength, chloride diffusion, and porosity are compared with electrical charges. This paper deals with the results of the concrete samples exposed for only 2 months, but it is a part of the total test plan for 100 years. From the work, time-dependent diffusion coefficients in HPC and the key parameters for durability design are proposed.

scholarly journals Service Life Prediction of Reinforced Concrete in a Sea-Crossing Railway Bridge in Jiaozhou Bay: A Case Study

2019 ◽  
Vol 9 (17) ◽  
pp. 3570 ◽  
Author(s):  
Zhe Li ◽  
Zuquan Jin ◽  
Tiejun Zhao ◽  
Penggang Wang ◽  
Lixiao Zhao ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Reliability Index ◽  
Life Prediction ◽  
Jiaozhou Bay ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Railway Bridge ◽  
Box Girder ◽  
The Mean

Reinforced bar corrosion induced by chloride ingression is one of the most significant threats to the durability of concrete structures in marine environments. The concrete cover thickness, compressive strength, chloride diffusion coefficient, and surface defects of reinforced concrete in the Jiaozhou Bay sea-crossing railway bridge were measured. The temperature and relative humidity in the concrete and the loading applied onto the reinforced concrete were monitored. Based on the DuraCrete model, a revised model for the service life prediction of concrete structures was established, considering the effects of temperature and loading on the chloride diffusion coefficient. Further, the reliability indexes of the reinforced concrete box girder, pier, and platform, located in the marine and land sections, in relation to service lives lasting various numbers of years, were calculated. The measured and calculated results show that the mean cover thicknesses of concrete piers in the marine and land sections are 52 mm and 36 mm, respectively, and the corresponding standard deviations are 5.21 mm and 3.18 mm, respectively. The mean compressive strengths of concrete in the marine and land sections are 56 MPa and 46 MPa, respectively. The corresponding standard deviations are 2.45 MPa and 2.67 MPa, respectively. The reliability indexes of the reinforced concrete box girder and platform in the marine section, under the condition of a service life of 100 years, are 1.81 and 1.76, respectively. When the corrosion-resistant reinforced bar was used in the pier structure in the marine section, its reliability index increased to 2.01. Furthermore, the reliability index of the reinforced concrete damaged by salt fog in the land section was 1.71.

Comparison of chloride penetration into surface-treated concrete in artificial and natural environments

2016 ◽  
Vol 20 (9) ◽  
pp. 1315-1324 ◽  
Author(s):  
Jianfeng Dong ◽  
Yuxi Zhao ◽  
Yueliang Gan ◽  
Chaomei Ding ◽  
Qiming He
Keyword(s):  
Diffusion Coefficients ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Natural Environments ◽  
Nacl Solution ◽  
Normal Concrete ◽  
Wetting And Drying

This study investigated the penetration of chloride into surface-treated high-performance concrete and normal concrete in natural and accelerated environments. Both high-performance concrete and normal concrete were applied in a real port. Concrete specimens that were cast together with the concrete port were transported to the laboratory and subjected to wetting and drying cycles with NaCl solution. The chloride contents of the specimens in the laboratory and the in situ components were tested. The chloride diffusion coefficients and surface chloride contents were calculated based on Fick’s second law. The results show that high-performance concrete and surface treatment clearly slow the chloride penetration into the concrete both in the laboratory and in situ. The chloride contents on the surface and in the concrete in the components of the concrete port are higher during the summer than during the winter. The chloride penetration performance in the concrete of real structures cannot be inferred from its performance in specimens under artificial environments in the laboratory.

scholarly journals Service Life Prediction and Lateral Bearing Capacity Analysis of Piles Considering Coupled Corrosion-Temperature Deterioration Processes

2021 ◽  
Vol 9 (6) ◽  
pp. 614
Author(s):  
Yue Li ◽  
Youliang Chen ◽  
Wei Shao ◽  
Juhui Zhang ◽  
Shaoming Liao ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Bearing Capacity ◽  
Chloride Concentration ◽  
Probabilistic Methods ◽  
Stiffness Degradation ◽  
Chloride Diffusion ◽  
Capacity Analysis ◽  
Chloride Diffusion Coefficient ◽  
Degradation Coefficient

High temperatures can enhance the chloride diffusion coefficient and this poses a threat to reinforced concrete (RC) piles. This study intends to propose predictive models that can evaluate the service life and lateral bearing behaviour of reinforced concrete piles subjected to marine environments and varying temperatures. The models show that temperature can accelerate the diffusion rate of chloride and increase the concentration of free chloride in concrete. The distribution law of chloride concentration is obtained by considering the ageing effect as well. Deterministic and probabilistic models are proposed to assess the time to corrosion initiation and propagation. The stiffness degradation coefficient is introduced in the analysis of the lateral bearing capacity of RC piles. The results show that high temperature can decrease the service life of piles and the life spans obtained from deterministic and probabilistic methods are similar; however, the predictions of the latter are more conservative. Temperature can enhance the current density and boost corrosion products, which leads to pile cracking. The rust appearing on the steel surface would make the stiffness degradation coefficient drop sharply. The lateral bearing capacity analysis is conducted from the perspectives of shear force, displacement and bearing moment of the piles.

Inner Damage and Anti-Chloride Penetration of High-Performance Concrete under Axial Tensile Load

2011 ◽  
Vol 261-263 ◽  
pp. 1210-1214
Author(s):  
Fu Xiang Jiang ◽  
Lei Xin ◽  
Tie Jun Zhao ◽  
Xiao Mei Wan
Keyword(s):  
Diffusion Coefficient ◽  
High Performance ◽  
High Performance Concrete ◽  
Tensile Load ◽  
Total Porosity ◽  
Tensile Loading ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Uniaxial Tensile ◽  
Chloride Diffusion Coefficient

The total porosity of high performance concrete specimens after different level uniaxial tensile loading were measured to reflect the damage degree of mechanical load to the microstructure of the concrete. Meanwhile, considering the environmental characteristics of the ocean tidal zone, chloride penetration tests of the concrete were carried out with salt solution capillary absorption method. Based on the profile of chloride measured from specimens, chloride diffusion coefficients of the concrete under uniaxial tensile load with different levels are determined further by Fick’s second law. Results show that both of total porosity and chloride diffusion coefficient of the concrete are increased significantly after short-term tensile loading. And the evolutions of the porosity and chloride diffusion coefficient are similar with the development of micro-cracks under uniaxial tensile load.

On the Time Dependency of the Chloride Diffusion in High Performance Concrete

2013 ◽  
Vol 721 ◽  
pp. 148-152
Author(s):  
Zheng Chen ◽  
Xi Bin Zhao ◽  
Yan Hua Yuan ◽  
Zhong Hua Wang ◽  
Lu Feng Yang ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Time Dependency ◽  
Long Period ◽  
Age Factor ◽  
Astm C1202

The chloride diffusion coefficient of concrete is time dependent. The high performance concrete (HPC) was prepared and the specimens were tested by ASTM C1202 and the durability of HPC in long period is analyzed with the time dependency of diffusion in this paper. The results show that the chloride diffusion coefficients of the HPC with only fly ash are large than those of the HPC with multi-admixtures, but the attenuation of the chloride diffusion coefficients of the formers are faster than the latters. The analysis results show that the chloride concentrations in concrete is over estimated when time-dependence of chloride diffusion is not considered, and the durability of concrete in long period is determined by both chloride diffusion coefficient and age factor.

scholarly journals Service Life and Early Age Durability Enhancement due to Combined Metakaolin and Nanosilica in Mortars for Marine Applications

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1169 ◽  
Author(s):  
Ramiro García ◽  
Encarnación Reyes ◽  
Paula Villanueva ◽  
Miguel Ángel de la Rubia ◽  
Jaime Fernández ◽  
...  
Keyword(s):  
Service Life ◽  
Synergistic Effect ◽  
High Performance ◽  
High Performance Concrete ◽  
Environmental Concern ◽  
Binding Capacity ◽  
Chloride Ion ◽  
Nano Particles ◽  
Chloride Diffusion ◽  
Marine Applications

The addition of a range of micro- and nano-particles to high-performance concrete has been the focus of recent research. At present, studies are mainly aimed at designing customised mortars, providing them with specific properties for each application. Improving the durability of mortars is one of the main objectives in such research, as a result of increasing environmental concern. The research presented herein analyses the synergistic effect of nanosilica and metakaolin as additives on the service life of cement-based mortars subject to aggressive environments (i.e., chloride exposure) at early ages. The effects of the additives on the durability properties of submerged samples after two and three days of curing were analysed. Tests were conducted on several different properties: resistivity, porosity, mechanical properties, chloride diffusion, and service life. It is observed that metakaolin and nanosilica exhibit a synergistic effect as additives, which is related to porosity refinement and chloride ion binding capacity, which contributes to enhanced resistance against chloride penetration from very early ages.

Application of High Performance Concrete with Compound Admixtures of Fly Ash and Perlite Powder in Pavement of Highway

2011 ◽  
Vol 413 ◽  
pp. 29-33 ◽  
Author(s):  
Le Hua Yu ◽  
Hui Ou ◽  
Shuang Xi Zhou
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Technical Specification ◽  
Chloride Ion ◽  
Aluminosilicate Glass ◽  
Chloride Diffusion ◽  
Chloride Salt ◽  
Chloride Diffusion Coefficient

Based on former experimental achievement in laboratory, application and construction of high performance concrete (HPC) in pavement of highway were introduced to the paper. The HPC was proportioned with compound admixtures of 12% fly ash and 12% perlite powder replacing cement in equal mass. Perlite powder of both is a new mineral admixture, originated natural volcanic rock perlite composed of mainly aluminosilicate glass, was ground to mostly under 45 μm so as to possess pozzolanic activity, and then added to concrete as a supplementary cementitious material to substitute for partial cement. Multiplex of the two admixtures is profitable to increase workability, mechanical properties and durability during post-stage for concrete in varying degrees. The testing slump and construction fit of the fresh concrete in situ were shown that both of admixtures improved workability of the concrete. HPC samples remained in field and drilled from pavement were determined and investigated on mechanical properties and durability by means of test. It has been observed by inspected result of that flexural strength of these concrete are above 5 MPa at 28 cured days and compression strength about 40 MPa. The indexes of their abrasion resistance distribute throughout 1.94—2.63 kilo-rotation/mm at 90 days. These measured mechanical characteristics are so large enough to the technical specification of heavy traffic grade highway on mechanical property. To investigate durability of the HPC, the charge passed and the chloride diffusion coefficient in concrete at 90 cured days obtained from the accelerated chloride migration test were determined with RCM experimental equipment. The values of charge passed in the concrete were lower and ranged in 449—928 Coulomb, which revealed that the HPC are also better permeability resistance of chloride ion and be able to sustain in environment of chloride salt for 100 years. The chloride diffusion coefficients of the HPC were scattered in 1.4—4.7×10-12m2s-1. These parameters exhibited completely the HPC better or excellent for electrical indication of concrete’s ability to resist chloride ion penetration referent to relevant standards and information.

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