scholarly journals Chloride diffusion models for plain and blended cement concretes exposed to laboratory and atmospheric marine conditions

2022 ◽  
Author(s):  
Khaled A. Alawi Al-Sodani ◽  
Mesfer Mohammad Al-Zahrani ◽  
Mohammed Maslehuddin ◽  
Omar S. Baghabra Al-Amoudi ◽  
Salah U. Al-Dulaijan
Keyword(s):  
Blended Cement ◽  
Diffusion Models ◽  
Chloride Diffusion

scholarly journals Comparative Study of Strength and Corrosion Resistant Properties of Plain and Blended Cement Concrete Types

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Velu Saraswathy ◽  
Subbiah Karthick ◽  
Han Seung Lee ◽  
Seung-Jun Kwon ◽  
Hyun-Min Yang
Keyword(s):  
Water Absorption ◽  
Corrosion Behaviour ◽  
Blended Cement ◽  
Effective Porosity ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability ◽  
Corrosion Resistant ◽  
Lower Corrosion Rate ◽  
Portland Slag Cement

The relative performances of mechanical, permeability, and corrosion resistance properties of different concrete types were compared. Concrete types were made from ordinary Portland cement (OPC), Portland pozzolana cement (PPC), and Portland slag cement (PSC). Compressive strength test, effective porosity test, coefficient of water absorption, short-term accelerated impressed voltage test, and rapid chloride permeability test (RCPT) were conducted on M30 and M40 grades of concrete designed with OPC, PPC, and PSC cements for 28- and 90-day cured concrete types. Long-term studies such as microcell and electrochemical evaluation were carried out to understand the corrosion behaviour of rebar embedded in different concrete types. Better corrosion resistant properties were observed for PSC concrete by showing a minimum current flow, lowest free chloride contents, and lesser porosity. Besides, PSC concrete has shown less coefficient of water absorption, chloride diffusion coefficient (CDC), and lower corrosion rate and thereby the time taken for initiation of crack extended.

Chloride diffusion models for Type I and fly ash cement concrete exposed to field and laboratory conditions

2021 ◽  
Vol 76 ◽  
pp. 102900
Author(s):  
Khaled A. Alawi Al-Sodani ◽  
Mesfer Mohammad Al-Zahrani ◽  
Mohammed Maslehuddin ◽  
Omar S. Baghabra Al-Amoudi ◽  
Salah U. Al-Dulaijan
Keyword(s):  
Fly Ash ◽  
Diffusion Models ◽  
Chloride Diffusion ◽  
Type I ◽  
Cement Concrete ◽  
Laboratory Conditions ◽  
Field And Laboratory Conditions

Chloride Diffusion in Blended Cement Concrete Made with Quartzite Recycled Aggregate

2012 ◽  
Vol 1488 ◽  
Author(s):  
Claudio J. Zega ◽  
Yury A. Villagrán-Zaccardi ◽  
Ángel A. Di Maio
Keyword(s):  
Blended Cement ◽  
Recycled Concrete ◽  
Water Soluble ◽  
Recycled Aggregate ◽  
Chloride Diffusion ◽  
Chloride Ingress ◽  
Chloride Diffusion Coefficient ◽  
Conventional Concrete ◽  
Concrete Production ◽  
The Relationship

ABSTRACTUsing waste materials as aggregate for new concrete production is a growing tendency, because of several environmental problems. Recycled coarse aggregate (RCA) obtained from crushing waste concrete has lower density and greater absorption than natural aggregate, because of the higher porosity of the mortar attached to the RCA particles. Compressive strength level achieved in recycled concrete may be similar to that of conventional concrete. On the other hand, durable performance of recycled concrete is variable, and diverse evidence can be found in literature for different durability issues. In this paper, chloride ingress in conventional and recycled concrete, made with quartzite aggregate and blended Portland cement is evaluated when immersed in NaCl solution. Two strength levels (21 and 35 MPa) and two contents of RCA (25 and 75%), as substitute of natural quartzite aggregate, were considered. The chloride diffusion coefficient and the relationship between water-soluble chloride and bound chloride are analyzed.

Relationships Between Permeability, Porosity, Diffusion And Microstructure Of Cement Pastes, Mortar, And Concrete At Different Temperatures

1988 ◽  
Vol 137 ◽  
Author(s):  
Della M. Roy
Keyword(s):  
Pore Structure ◽  
Elevated Temperatures ◽  
Mercury Porosimetry ◽  
Blended Cement ◽  
Ionic Species ◽  
Chloride Diffusion ◽  
Concrete Durability ◽  
Chloride Permeability ◽  
Cement Pastes ◽  
Blended Cements

AbstractPermeabilities to water and diffusion of ionic species in cementitious grouts, pastes and mortars are important keys to concrete durability. Investigations have been made of numerous materials containing portland and blended cements, and those with fine-grained filler, at room temperature and after prolonged curing at several elevated temperatures up to 90°C. These constitute part of studies of fundamental material relationships performed in order to address the question of long-term durability. In general, the permeabilities of the materials have been found to be low [many <10−8 Darcy (10−13 m·s−1)] after curing for 28 days or longer at temperatures up to 60°C. The results obtained at 90°C are somewhat more complex. In some sets of studies of blended cement pastes with w/c varying from 0.30 to 0.60 and cured at temperatures up to 90°C the more open-pore structure (at the elevated temperature and higher w/c) as evident from SEM microstructural studies as well as mercury porosimetry are generally correlated also with a higher permeability to liquid. The degree of bonding and permeability evident in paste or mortar/rock interfacial studies present somewhat more conflicting results. The bond strength (tensile mode) has been shown to be improved in some materials with increased temperature. The results of permeability studies of paste/rock couples show examples with similar low permeabilities, and some with increased permeability with temperature.Ionic diffusion studies also bring important bearing to understanding the effect of pore structure. The best interrelationships between chloride diffusion and pore structure appear to relate diffusion rate to median pore size. Similar results were found with “chloride permeability” test.

scholarly journals Chloride-Induced Corrosion of Steel in Concrete: An Overview on Chloride Diffusion and Prediction of Corrosion Initiation Time

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Muhammad Umar Khan ◽  
Shamsad Ahmad ◽  
Husain Jubran Al-Gahtani
Keyword(s):  
Diffusion Models ◽  
Chloride Diffusion ◽  
Second Law ◽  
Chloride Ingress ◽  
Initiation Time ◽  
Chloride Binding ◽  
Rc Structures ◽  
Corrosion Initiation ◽  
Corrosion Initiation Time ◽  
Corrosion Of Steel

Initiation of corrosion of steel in reinforced concrete (RC) structures subjected to chloride exposures mainly depends on coefficient of chloride diffusion, Dc, of concrete. Therefore, Dc is one of the key parameters needed for prediction of initiation of reinforcement corrosion. Fick’s second law of diffusion has been used for long time to derive the models for chloride diffusion in concrete. However, such models do not include the effects of various significant factors such as chloride binding by the cement, multidirectional ingress of chloride, and variation of Dc with time due to change in the microstructure of concrete during early period of cement hydration. In this paper, a review is presented on the development of chloride diffusion models by incorporating the effects of the key factors into basic Fick’s second law of diffusion. Determination of corrosion initiation time using chloride diffusion models is also explained. The information presented in this paper would be useful for accurate prediction of corrosion initiation time of RC structures subjected to chloride exposure, considering the effects of chloride binding, effect of time and space on Dc, and interaction effect of multidirectional chloride ingress.

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