scholarly journals Effect of SiO2 Sol/Silane Emulsion in Reducing Water and Chloride Ion Penetration in Concrete

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 682
Author(s):  
Yongjuan Geng ◽  
Shaochun Li ◽  
Dongshuai Hou ◽  
Xu Chen ◽  
Zuquan Jin
Keyword(s):  
Contact Angle ◽  
Hydrophobic Effect ◽  
Chloride Ion ◽  
Treatment Method ◽  
Chloride Diffusion ◽  
Capillary Absorption ◽  
Test Results ◽  
Ion Diffusion ◽  
Chloride Ion Penetration ◽  
Hydrophobic Treatment

Here, a new concrete hydrophobic treatment method is developed using SiO2 sol and silane emulsion. The effectiveness of the modification for concrete protection is evaluated through testing water absorption and chloride diffusion. Two types of concrete with different strength grades (C40, C50) are used as the research object. The results show that the water capillary absorption coefficient and chloride ion diffusion coefficient of concrete decrease greatly under the protection of SiO2 sol and silane emulsion. Additionally, the protection effect is better with the increase of SiO2 consumption. Contact angle test results reveal that when the coating amount of SiO2 sol and silane emulsion is 300 g/m2, respectively, the contact angle reaches 150.2°, indicating the concrete (C40) surface reaches the superhydrophobic state. Through scanning electron microscope (SEM) observation, it is found that the hydrophobic effect of the SiO2 sol/silane emulsion is mainly due to the change in the surface morphology of concrete (C40).

EFFECT OF CRUMB RUBBER ON CONCRETE STRENGTH AND CHLORIDE ION PENETRATION RESISTANCE

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Nurazuwa Md Noor ◽  
H. Hamada ◽  
Y. Sagawa ◽  
D. Yamamoto
Keyword(s):  
Structural Strength ◽  
Salt Water ◽  
Chloride Ion ◽  
Crumb Rubber ◽  
Rubberized Concrete ◽  
Migration Test ◽  
Ion Diffusion ◽  
Steady State Condition ◽  
Chloride Ion Penetration ◽  
Chloride Ion Diffusion

This paper present the effect of crumb rubber on its ability to produce concrete with structural strength when it was used directly from the plant without any treatment process. Crumb rubber was added as fine aggregates at 0%, 10%, 15% and 20% of sand volume meanwhile silica fume was added at 10% by cement weight. Three main series of concrete namely rubberized concrete with water-to-cement ratio of 50% and 35% was design and development of compressive strength was observed from day 7 until 91 days. Also, effectiveness of crumb rubber under flexural strength and splitting tensile strength was studied at 28 days curing age. Effect of crumb rubber on durability performance was done on chloride ion penetration resistance performance by migration test and by immersion in salt water. Chloride ion diffusion in rubberized concrete by migration test was carried out under steady state condition using effective diffusion coefficient, De meanwhile, immersion test in salt water was conducted under non-steady state condition using apparent diffusion coefficient, Da. Results showed that compressive strength was decrease with the increasing of crumb rubber in the mixture.  Even though the strength were reducing with the inclusion of crumb rubber, the reduction were less than 50% and it achieved acceptable structural strength. Chloride transport characteristics were improved by increasing amount of CR and rubberized concrete with w/c = 0.35 gave better resistance against chloride ion compared to w/c = 0.50 with more than 50% difference. Silica fume provide slightly strength increment compared to normal rubberized concrete and the same behavior was observed during chloride ion diffusion test.

The Chloride Ion Penetration Model Coupled with Temperature and Moisture Transfer in Marine Environment

2012 ◽  
Vol 591-593 ◽  
pp. 2422-2427
Author(s):  
Juan Zhao
Keyword(s):  
Marine Environment ◽  
Moisture Transfer ◽  
Regional Climate ◽  
Chloride Ion ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Tidal Zone ◽  
Analog Simulation ◽  
Chloride Ion Penetration ◽  
Ion Penetration

Considering the complexity of the chloride ion penetration in concrete exposed to marine environment, an integrated chloride penetration model coupled with temperature and moisture transfer is proposed. The governing equations and parameters embody fully the cross-impacts among thermal conduction, moisture transfer and chloride ion penetration. Furthermore, the four exposure conditions are classified based on the different contact with the aggressive marine environment, and then the micro-climate condition on the concrete surface is investigated according to the regional climate characteristics, therefore, a comprehensive analog simulation to the chloride penetration process is proposed. To demonstrate that the proposed numerical model can correctly simulate the chloride diffusion in concrete, the integrated chloride diffusion model is applied in reproducing a real experiment, finally the model gives good agreement with the experimental profiles, and it is proved the tidal zone exposure results in a more severe attack on the reinforcement

Ultra-Low Cement Dosage Hill Sand Concrete’s Electric Flux and Carbonization Performance Study

2014 ◽  
Vol 584-586 ◽  
pp. 1332-1336
Author(s):  
Wei Wei Hu ◽  
Li Bin Xu ◽  
Yi Dong ◽  
Xiao Peng Nie
Keyword(s):  
Materials Science ◽  
Chloride Ion ◽  
Social Stability ◽  
Concrete Durability ◽  
Test Results ◽  
Performance Study ◽  
Chloride Ion Penetration ◽  
Concrete Materials ◽  
Electric Flux ◽  
Low Dosage

Concrete durability is closely related to the national economy and social stability, environmental protection, sustainable development is a major research topic concrete materials science, engineering and technological problems are a major concern. This paper studies resistance to chloride Ion penetration performance and anti-carbonation of low cement concrete sand hill. And combined with the test results analysis and discussion the low dosage of cement to sand concrete electric flux and the influence of carbonization resistance.

scholarly journals Effect of Fly Ash as Cement Replacement on Chloride Diffusion, Chloride Binding Capacity, and Micro-Properties of Concrete in a Water Soaking Environment

2020 ◽  
Vol 10 (18) ◽  
pp. 6271 ◽  
Author(s):  
Jun Liu ◽  
Jiaying Liu ◽  
Zhenyu Huang ◽  
Jihua Zhu ◽  
Wei Liu ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Binding Capacity ◽  
Chloride Ion ◽  
Chloride Content ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Binding ◽  
Test Results ◽  
New Equation

This paper experimentally studies the effects of fly ash on the diffusion, bonding, and micro-properties of chloride penetration in concrete in a water soaking environment based on the natural diffusion law. Different fly ash replacement ratio of cement in normal concrete was investigated. The effect of fly ash on chloride transportation, diffusion, coefficient, free chloride content, and binding chloride content were quantified, and the concrete porosity and microstructure were also reported through mercury intrusion perimetry and scanning electron microscopy, respectively. It was concluded from the test results that fly ash particles and hydration products (filling and pozzolanic effects) led to the densification of microstructures in concrete. The addition of fly ash greatly reduced the deposition of chloride ions. The chloride ion diffusion coefficient considerably decreased with increasing fly ash replacement, and fly ash benefits the binding of chloride in concrete. Additionally, a new equation is proposed to predict chloride binding capacity based on the test results.

scholarly journals Durability of structural lightweight waste aggregate concrete – electrical resistivity

2020 ◽  
Vol 310 ◽  
pp. 00015 ◽  
Author(s):  
Marie Hornakova ◽  
Petr Konecny ◽  
Petr Lehner ◽  
Jacek Katzer
Keyword(s):  
Electrical Resistivity ◽  
Lightweight Concrete ◽  
Chloride Ion ◽  
Plain Concrete ◽  
Degradation Process ◽  
Chloride Diffusion ◽  
Ion Diffusion ◽  
Concrete Mixtures ◽  
New Type ◽  
Concrete Matrix

While examination of the durability of ordinary concrete mixtures is of interest of many research groups, only limited amount of information is available in terms of lightweight concrete tested under the same conditions. In this case, the durability related to the chloride ion diffusion is investigated on the relatively new type of structural lightweight concrete, which, above all, contains waste material – red ceramics sand, and artificial expanded clay coarse aggregate. Used aggregates were fully soaked before adding into the concrete mixture, so also the internal curing effect is considered in terms of the degradation process. Cylindrical specimens made of plain concrete matrix and with added fibre in various percentage quantities were tested to examine the durability of the mixture by measuring the electrical resistivity. The results are compared to the findings from a similar project. The paper deals with aspects influencing the results of chloride diffusion in concrete.

Durability of Self-Compacting Concrete

2011 ◽  
Vol 324 ◽  
pp. 340-343
Author(s):  
Abdelaziz Benmarce ◽  
Hocine Boudjehem ◽  
Robila Bendjhaiche
Keyword(s):  
Oxygen Permeability ◽  
Chloride Ion ◽  
Chemical Characteristics ◽  
Capillary Absorption ◽  
Ion Diffusion ◽  
Self Compacting Concrete ◽  
Fresh State ◽  
Physical And Chemical ◽  
Transfer Properties ◽  
Chloride Ion Diffusion

Abstract. Self compacting concrete (SCC) seem to be a very promising materials for construction thanks to their properties in a fresh state. Studying of the influence of the parameters of specific designed mixes to their mechanical, physical and chemical characteristics in a state hardened is an important stage so that it can be useful for new-to-the-field researchers and designers (worldwide) beginning studies and work involving self compacting concrete. The objective of this research is to study the durability of self compacting concrete. The durability of concrete depends very much on the porosity; the latter determines the intensity of interactions with aggressive agents. The pores inside of concrete facilitate the process of damage, which began generally on the surface. We are interested to measure the porosity of concrete on five SCC with different compositions (w/c, additives) and vibrated concrete to highlight the influence of the latter on the porosity, thereafter on the compressive strength and the transfer properties (oxygen permeability, chloride ion diffusion, capillary absorption).

Life Prediction Model for Nuclear Power Plant Intake Structure Exposed to Chloride Environment Based on Similarity Principle

2020 ◽  
Author(s):  
Sen Chen ◽  
Zhen Wang ◽  
Jiangtao Zhang ◽  
Dahua Cai ◽  
Jiyun Zhou
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Salt Spray ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Test Results ◽  
Ion Diffusion ◽  
Similarity Principle ◽  
Intake Structure

Abstract Three environmental simulation experiments for accelerating the chloride ingress were designed based on the similarity principle and the actual Nuclear Power Plant (NPP) intake structure service environment parameters including alternate drying-wetting condition, immersion condition and salt spray condition. Different experiment conditions were designed for each three-simulation experiment condition based on the similarity principle. The temperature, chloride ion concentration and dry-wet cycle time ratio were selected parameters for alternation wetting-drying experiments. The temperature and chloride ion concentration were selected parameters for the salt spray experiment and immersion experiment. The distribution of chloride ion concentration along the depth of the concrete samples were measured every 30 days. The testing results showed that chloride ion diffusion depth is maximum under the dry-wet cycle test, chloride ion diffusion depth is minimum under salt spray test. The curves of the chloride ion concentration along depth increased firstly and then decreased, which is consistent with the two-dimension diffusion law. Finally, a life prediction model that can be used to predict the concrete structure of the existing coastal nuclear power plant was developed based on the test results and field test results.

Research on Chloride Diffusion Model of PC with Chloride Attack in Marine Atmosphere Zone

2014 ◽  
Vol 711 ◽  
pp. 481-484
Author(s):  
Yu Chen ◽  
Jie Xu ◽  
Rong Gui Liu ◽  
Su Bi Chen ◽  
Yuan Gao
Keyword(s):  
Prestressed Concrete ◽  
Concentration Distribution ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Chloride Diffusion ◽  
Marine Atmosphere ◽  
Ion Diffusion ◽  
Chloride Ion Diffusion

Based on the existing studies about chloride ion erosion in prestressed concrete structures, this paper intends to discuss the effects of the stress level and environment factors (including temperature and humidity, etc.) on chloride ion diffusion under marine atmosphere zone. The investigation from pre-stressed concrete crossbeams which service for 39 years in Lianyungang Port shows the chloride ion concentration distribution and chloride ion diffusion. According to the chloride ion concentration distribution, it finds that chloride ion concentration values in pre-concrete structures is Cmax,1> Cmax,2. In addition, the free chloride concentration distribution values go down smoothly after the second peak. Therefore, the result shows that the improved model can be used in marine atmosphere zone.

Effect of Sulfate Ion to Chloride Ion Transmission in Concrete under Flexural Load

2011 ◽  
Vol 90-93 ◽  
pp. 2798-2802
Author(s):  
Zu Quan Jin ◽  
Qi Chang Zhuang ◽  
Jie Lin
Keyword(s):  
Diffusion Coefficient ◽  
Chloride Ion ◽  
Chloride Diffusion ◽  
Main Role ◽  
Chloride Diffusion Coefficient ◽  
Ion Diffusion ◽  
Sulfate Ion ◽  
Load Rate ◽  
Negative Effect ◽  
Ion Transmission

Chloride ion ingression into concrete under flexural load is investigated in the paper. Concrete specimens have been stored in 3.5%NaCl solution or 3.5%NaCl + 5%Na2SO4 solution for 210 days. The effect of flexural load and sulfate ion to chloride ion transmission is studied. The experimental results show that sulfate ion reduces chloride ion transmission in concrete. But when concrete under flexural load, Sulfate ion has plus and minus effect on chloride ion ingression into concrete. When the flexural load rate is low, sulfate ion reduces chloride ion transmission. But the flexural load is high, the negative effect of sulfate corrosion plays a main role. When concrete exposed to 3.5%NaCl+5%Na2SO4 solution, chloride ion diffusion coefficient of concrete in tensile zone increases with flexural load. And in compressive zone, the chloride diffusion coefficient decreases first and then raises with increasing flexural load.

Durability Assessment of Hot Dip Galvanized Reinforcement Concrete

2010 ◽  
Vol 177 ◽  
pp. 533-536
Author(s):  
Quan Jiang ◽  
Yu Jun Liu ◽  
Ru Ping Liu
Keyword(s):  
Chloride Ion ◽  
Concrete Specimen ◽  
Test Results ◽  
Tidal Zone ◽  
Accelerated Corrosion ◽  
Protection Efficiency ◽  
Chloride Ion Penetration ◽  
Steel Bars ◽  
Durability Assessment ◽  
Accelerated Corrosion Test

Treat the steel bars by hot dip galvanizing technology to prepare steel concrete specimen. Adopt artificial accelerated corrosion test to simulate the seawater corrosive environment in continuous immersion zone and tidal zone and carry out accelerated corrosion for the concrete bars. Add NaCl whose cement content is 1%, 5% and 7% respectively in the concrete specimen to improve the chloride ion content in the system and simulate the strong corrosion environment. This thesis examines the corrosion influence of chloride ion penetration on the ordinary bars and hot-dip steel bars. It also assesses the corrosion protection efficiency for hot dip galvanized reinforcement (HDGR) by half cell method and analyzes the test results.

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