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.

scholarly journals Effects after 1500 Hardening Days on the Microstructure and Durability-Related Parameters of Mortars Produced by the Incorporation of Waste Glass Powder as a Clinker Replacement

2021 ◽  
Vol 13 (7) ◽  
pp. 3979
Author(s):  
Rosa María Tremiño ◽  
Teresa Real-Herraiz ◽  
Viviana Letelier ◽  
Fernando G. Branco ◽  
José Marcos Ortega
Keyword(s):  
Diffusion Coefficient ◽  
Water Absorption ◽  
Glass Powder ◽  
Cementitious Materials ◽  
Cement Industry ◽  
Waste Glass ◽  
Supplementary Cementitious Materials ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Waste Glass Powder

One of the ways of lessening the CO2 emissions of cement industry consists of replacing clinkers with supplementary cementitious materials. The required service life of real construction elements is long, so it is useful to characterize the performance of these materials in the very long term. Here, the influence of incorporating waste glass powder as a supplementary cementitious material, regarding the microstructure and durability of mortars after 1500 hardening days (approximately 4 years), compared with reference mortars without additions, was studied. The percentages of clinker replacement by glass powder were 10% and 20%. The microstructure was studied using impedance spectroscopy and mercury intrusion porosimetry. Differential thermal and X-ray diffraction analyses were performed for assessing the pozzolanic activity of glass powder at the end of the time period studied. Water absorption after immersion, the steady-state diffusion coefficient, and length change were also determined. In view of the results obtained, the microstructure of mortars that incorporated waste glass powder was more refined compared with the reference specimens. The global solid fraction and pores volume were very similar for all of the studied series. The addition of waste glass powder reduced the chloride diffusion coefficient of the mortars, without worsening their behaviour regarding water absorption after immersion.

Influence of the Nanomaterials of Kaolin Content on the Chloride Permeability of Cement Mortar

2017 ◽  
Vol 730 ◽  
pp. 406-411 ◽  
Author(s):  
Xiao Yu Guo ◽  
Ying Fang Fan ◽  
Kun Yang
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Cement Mortar ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability

This study investigated the influence of nanokaolin content on the behavior of cement mortar at various curing ages. The fluidity, chloride permeability, bending and compressive strength of cement mortar with various nanokaolin additives were examined. The addition of 0%, 1%, 2%, 3%, 4%, 5% and 6% nanokaolin were taken into consideration. The results showed that the addition of nanokaolin decreases the fluidity of cement mortar, and the fluidity the cement mortar decreases with the increase of nanokaolin additives. It is obtained that the addition of nanokaolin increases both the bending and compressive strength of cement mortar, and with the increase of nanokaolin additives, the bending and compressive strength of cement mortar increase. The addition of 4% nanokaolin can result in a significant low chloride permeability of cement mortar among the seven dosages. The chloride diffusion coefficient of the mortar with the addition of 4% nanokaolin was decreased by 18.93%, 12.68% and 31.05% at 7, 14 and 28 curing days, respectively.

scholarly journals Influence of Parent Concrete Properties on Compressive Strength and Chloride Diffusion Coefficient of Concrete with Strengthened Recycled Aggregates

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4631 ◽  
Author(s):  
Jingwei Ying ◽  
Zewen Han ◽  
Luming Shen ◽  
Wengui Li
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Water Absorption ◽  
Recycled Aggregates ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Wide Range ◽  
Different Types ◽  
Compressive Strength Of Concrete ◽  
Silica Slurry

Parent concrete coming from a wide range of sources can result in considerable differences in the properties of recycled coarse aggregate (RCA). In this study, the RCAs were obtained by crushing the parent concrete with water-to-cement ratios (W/Cparent) of 0.4, 0.5 and 0.6, respectively, and were strengthened by carbonation and nano-silica slurry wrapping methods. It was found that when W/Cparen was 0.3, 0.4 and 0.5, respectively, compared with the mortar in the untreated RCA, the capillary porosity of the mortar in the carbonated RCA decreased by 19%, 16% and 30%, respectively; the compressive strength of concrete containing the carbonated RCA increased by 13%, 11% and 13%, respectively; the chloride diffusion coefficient of RAC (DRAC) containing the nano-SiO2 slurry-treated RCA decreased by 17%, 16% and 11%; and that of RAC containing the carbonated RCA decreased by 21%, 25% and 26%, respectively. Regardless of being strengthened or not, both DRAC and porosity of old mortar in RCAs increased with increasing W/Cparent. For different types of RCAs, DRAC increased obviously with increasing water absorption of RCA. Finally, a theoretical model of DRAC considering the water absorption of RCA was established and verified by experiments, which can be used to predict the DRAC under the influence of different factors, especially the water absorption of RCA.

Influence of Fly Ash to Concrete Protecting Steel Corrosion Ability

2015 ◽  
Vol 744-746 ◽  
pp. 169-172 ◽  
Author(s):  
Qiao Yang ◽  
Xiao E Zhu
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Water Absorption ◽  
Permeability Coefficient ◽  
Corrosion Potential ◽  
Steel Corrosion ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Concrete Permeability ◽  
The Common

The compressive strengths of the concrete cubes added fly ash were increased 53.2%, the density was almost unchanged, but the water absorption was decreased 30%. The concrete permeability coefficient and chloride diffusion coefficient added fly ash were lower than the common concrete at all ages. The concrete specimens corrosion potential added fly ash were higher than-300mV, while common concrete almost were lower than-500mV. Corrosion probability was small and there was no crack and corrosion pot on the surface of the specimens until 82 times cycles in wet-dry chlorides solution. Fly ash in concrete has obvious act for improving concrete behavior in protecting the embedded steel in corrosion.

scholarly journals EFFECTS OF BLAST FURNACE SLAG ON CHLORIDE PERMEABILITY OF CONCRETE

2012 ◽  
Vol 15 (2) ◽  
pp. 70-80
Author(s):  
Mien Van Tran ◽  
Yen Thi Hai Nguyen ◽  
Thi Nguyen Cao
Keyword(s):  
Diffusion Coefficient ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Binding Capacity ◽  
Concrete Strength ◽  
Steel Reinforcement ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability ◽  
Furnace Slag

Chloride-induced corrosion of steel reinforcement is the main cause of deterioration of reinforced concrete structures in marine environments. The penetration of chlodride ions into concrete cover that accelerates corrosion process of steel reinforcement, this affects the bearing capacity of structures. This paper investigates on chloride permeability cheracteristic of concrete using blast furnace slag in terms of chloride diffusion coefficient and chloride binding capacity. The concrete used in this research has grade of 45MPa and the slag content replacement of cement PC50 is in range of 0% - 70%. The chloride diffusion coefficient of concrete is determined by ASTM C1202 and NordTest NT Build 492. Results showed that the blast furnace slag replacement increases (from 0% to 50%), the chloride ion diffusion coeffient decreases and bound chloride content in concrete increases. It is clear to conclude that blast furnace slag can be used to replace cement PC50 in range of 30% to 40% in order to increase the resistance of concrete to chloride penetration without affecting concrete strength.

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.

Evaluation of Relationship between Innitial Current, Conductance, Chloride Diffusion Coefficient and Charge Passed of Concrete

2011 ◽  
Vol 399-401 ◽  
pp. 1200-1203 ◽  
Author(s):  
Yan Jun Hu ◽  
Yan Liang Du ◽  
Wei Zhang
Keyword(s):  
Diffusion Coefficients ◽  
Test Methods ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability ◽  
Wetting And Drying ◽  
Alternate Wetting And Drying ◽  
Drying Test

In this study, plain and mineral admixture (slag, fly ash and silica fume) modified concrete prisms were made with three water-to-binder ratios (w/b), and four test methods (Rapid Chloride Permeability Test-ASTM C1202-91, AC Conductance Test, 150-days Ponding Test, Alternate Wetting and Drying Test by cyclic loading with salt solution and drying) were employed to measure the concrete prisms’ chloride penetrability. The effects of mineral admixtures on the concrete chloride permeability were discussed, and the correlation of results separately obtained from the four test methods were analyzed. The experiment results indicate that blending concrete is beneficial with regard to the resistance against chloride ion penetration, and good linear ralationship between charge passed and innitial current, charge passed and conductance, charge passed and chloride diffusion coefficients by 150-days Ponding Test, charge passed and diffusion coefficients by Alternate Wetting and Drying Test were obtained.

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