scholarly journals Experimental Study on the Evaluation of Physical Performance and Durability of Cement Mortar Mixed with Water Repellent Impregnated Natural Zeolite

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3288 ◽  
Author(s):  
Chang Bok Yoon ◽  
Han Seung Lee
Keyword(s):  
Natural Zeolite ◽  
Test Specimen ◽  
Cement Mortar ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Water Repellent ◽  
Chloride Diffusion Coefficient ◽  
Accelerated Carbonation ◽  
Penetration Test ◽  
Water Penetration

To complement the shortcomings of concrete surface treatment technology and improve the durability of concrete structure, the purpose of this study was to impregnate water-repellent performance into natural zeolite, which has many pores inside, to achieve water-repellent performance inside concrete. The physical performance and durability of cement mortar mixed with water-repellent natural zeolite was evaluated. Cement mortars were prepared by mixing ZWR1%, 3%, and 5% (ZWR: Zeolite + Water Repellent impregnation) in cement powder, and compressive strength, contact angle, water penetration test, resistance chloride penetration test, chloride diffusion coefficient, and accelerated carbonation test were evaluated. When the mixing ratio of ZWR increased, the compressive strength of the test specimen was reduced compared to OPC. In contact angle measurement, water penetration test, chloride penetration resistance test, chloride diffusion coefficient, and accelerated carbonation test, the ZWR-containing samples showed superior properties compared to OPC. It was found that the durability test results improved as the amount of mixing was increased, and the durability of the test specimen containing 5% ZWR was found to be the best.

scholarly journals Selection of the Optimum Carrier for Manufacturing Water-Repellent Concrete and Durability Evaluation of Cement Mortar Using It

2020 ◽  
Vol 10 (24) ◽  
pp. 9097
Author(s):  
Chang Bok Yoon ◽  
Han Seung Lee
Keyword(s):  
Natural Zeolite ◽  
Ordinary Portland Cement ◽  
Cement Mortar ◽  
Chloride Ion ◽  
Water Repellency ◽  
Water Repellent ◽  
Penetration Test ◽  
Water Penetration ◽  
Chloride Ion Penetration ◽  
Selection Of

The purpose of this experiment was to complement the shortcomings of existing surface treatment methods and to implement water repellency inside concrete to prevent water penetration and improve the durability of concrete. Carriers to provide water repellency were fabricated using fly ash (FA), silica fume (SF), and natural zeolite which are used as admixtures for concrete. They were mixed with cement mortar, tested, and evaluated. The compressive strength of the water-repellent impregnated natural zeolite (ZWR) specimen was 83% of that of ordinary Portland cement (OPC), and its contact angle was found to be 124°. The water penetration test and chloride ion penetration test confirmed that the water absorption and total passing charge were reduced, while the porosity and pore size were improved. For the other specimens, except ZWR, water repellency was judged to be insufficient due to the low fixing ability for the water-repellent’s active ingredient. The results of evaluating the physical performance and durability of cement mortar for the selection of the optimum carrier revealed that powders other than ZWR are not suitable as a material for providing water repellency to concrete.

scholarly journals Experimental Study on Effective Chloride Diffusion Coefficient of Cement Mortar by Different Electrical Accelerated Measurements

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 240
Author(s):  
Jianlan Chen ◽  
Jiandong Wang ◽  
Rui He ◽  
Huaizhu Shu ◽  
Chuanqing Fu
Keyword(s):  
Diffusion Coefficient ◽  
Cement Mortar ◽  
Early Stage ◽  
Chloride Concentration ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Good Consistency ◽  
Determination Methods

This study investigated the effective chloride diffusion coefficient of cement mortar with different water-to-cement ratio (w/c) under electrical accelerated migration measurement. The cumulative chloride concentration in anode cell solution and the cumulative chloride concentration drop in the cathode cell solution was measured by RCT measurement and the results were further used to calculate the chloride diffusion coefficient by Nordtest Build 355 method and Truc method. The influence of w/c on cement mortar’s chloride coefficient was investigated and the chloride diffusion coefficient under different determination methods were compared with other researchers’ work, a good consistency between this work’s results and literatures’ results was obtained. The results indicated that the increased w/c of cement mortar samples will have a higher chloride diffusion coefficient. The cumulative chloride concentration drop in the cathode cell solution will have deviation in early stage measurement (before 60 h) which will result in overestimation of the effective chloride diffusion coefficient.

scholarly journals Influence of Pore Structure on Chloride Penetration in Cement Pastes Subject to Wetting-Drying Cycles

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Honglei Chang ◽  
Zhiwu Zuo ◽  
Mingyue Qu ◽  
Fei Wang ◽  
Zhi Ge ◽  
...  
Keyword(s):  
Pore Structure ◽  
Penetration Rate ◽  
Error Function ◽  
Chloride Concentration ◽  
Total Porosity ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Cement Pastes ◽  
The Matrix

Copious studies have discovered a phenomenon that a chloride concentration peak appears on the surface of concrete under cyclic drying-wetting environments. In such cases, the chloride diffusion coefficient (D) obtained through directly fitting the standard error function of Fick’s second law is no longer accurate. The more reliable D obtained by the method proposed by Andrade is employed in this research to investigate the influence of pore structure on chloride penetration rate of pastes. The results show that both the effective coefficient (Deff) and the apparent coefficient (Dapp) increase with total porosity, the most probable pore size, and water absorption porosity, suggesting that the increase of the three pore structure parameters accelerates chloride penetration rate under cyclic wetting-drying condition. The increase of the three parameters makes more room available and eases the difficulty for salt solution to enter the matrix and thus leads to the augmentation of chloride transporting in matrix.

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.

Influence of Stone Dust in Manufactured Sand on Resisting Chloride Penetration in Marine Concretes

2012 ◽  
Vol 174-177 ◽  
pp. 1419-1423
Author(s):  
Jian Bo Xiong ◽  
Peng Ping Li ◽  
Sheng Nian Wang
Keyword(s):  
Diffusion Coefficient ◽  
Pore Structure ◽  
Binding Capacity ◽  
Chloride Penetration ◽  
Dust Content ◽  
Chloride Diffusion ◽  
Fine Aggregate ◽  
Chloride Diffusion Coefficient ◽  
Manufactured Sand ◽  
Stone Dust

In China, manufactured sand has been widely used as fine aggregate in concrete. Therefore, it is necessary to investigate the effect of manufactured sand on durability of concrete. This research studies the influence of stone dust content in manufactured sand on resisting chloride penetration in marine concrete by strength and other physical mechanical tests, XRD, TGA and pore structure analysis. Test results have shown that the chloride diffusion coefficient increased with increasing the stone dust content in manufactured sand when the stone dust content increasing from 3% to 13%. The stone dust in fine aggregate was participated in hydration procedure of cementitious, which will promote the hydration degree of cementitious and increase the chloride binding capacity of hydration product. The influence of stone dust in fine aggregate on chloride diffusion coefficient were the combined effects of concrete pore structure and cementitious hydration products, and the porosity and pore size distribution were the main factors that influence the changes of diffusion coefficient.

The Effect of Modified Hydrotalcites on Mechanical Properties and Chloride Penetration Resistance in Cement Mortar

2014 ◽  
Vol 629-630 ◽  
pp. 156-161
Author(s):  
Zheng Xian Yang ◽  
Hartmut Fischer ◽  
Rob Polder
Keyword(s):  
Cement Mortar ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Diffusion Resistance ◽  
Diffusion Test ◽  
Chloride Migration ◽  
Cement Mortars ◽  
Minor Influence ◽  
Chloride Penetration Resistance ◽  
And Diffusion

In this paper, two types of modified hydrotalcites (MHT) were incorporated into cement mortars with two dosage levels (replacing 5% and 10% cement by mass). Designated testing programme including strength test, porosity test, and rapid chloride migration and diffusion test were employed to investigate the effect of modified hydrotalcites on chloride penetration in cement mortar. The results based on these tests showed the incorporation of MHT-pAB at 5% dosage in mortar specimens produced a notably improved chloride diffusion resistance with no or minor influence on the development of mechanical strength.

scholarly journals Limitations of sorptivity and water permeability for the estimation of the chloride penetration rate in concrete regarding the accomplishment of prescriptive design for durability in the marine environment

2018 ◽  
Vol 8 (3) ◽  
pp. 301-316
Author(s):  
Yury A Villagrán Zaccardi ◽  
María E Sosa ◽  
Ángel A Di Maio
Keyword(s):  
Marine Environment ◽  
Diffusion Rate ◽  
Penetration Rate ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Capillary Absorption ◽  
Chloride Ingress ◽  
Water Penetration ◽  
Conventional Concrete

This paper presents an analysis of experimental data from conventional concrete regarding sorptivity and penetrability under pressure comparing these parameters to chloride diffusion rate determined in the laboratory and in actual marine environment. Prescriptions for durability assurance of reinforced concrete structures is based on the qualitative characterization of transport properties. For the specific case of the marine environment, it is required to assess the resistance of concrete to chloride ingress. The results show the limitations of both parameters as prescriptive indexes, with capillary absorption rate showing some advantages over water penetration under pressure.

Durability of Concrete for Thermal Insulation Composite Wall

2013 ◽  
Vol 438-439 ◽  
pp. 314-317
Author(s):  
Feng Lan Li ◽  
Hai Na Chen ◽  
Xue Zhen Feng ◽  
Su Yang
Keyword(s):  
Thermal Insulation ◽  
Coarse Aggregate ◽  
Cement Mortar ◽  
Chloride Penetration ◽  
Fine Aggregate ◽  
Volume Percent ◽  
Water Penetration ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Composite Wall

Tests were carried out to study the durability of fine aggregate concrete and composite concrete simultaneously provided by the wet-sieving technique for the thermal insulation composite wall as building envelops. The workability of every concrete satisfied the basic requirement of cast quality. The composition analyses of concrete showed that compared with the ordinary concrete, the volume percent of coarse aggregate was increased and the volume percent of cement mortar was decreased due to that the residual coarse aggregate stayed on the sieve was blended with ordinary concrete, which increased the resistances of composite concrete to chloride penetration, water penetration and carbonization. Meanwhile, the resistances of fine aggregate concrete to chloride penetration, water penetration and carbonization were reduced due to the obvious increase of the volume percent of cement mortar.

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.

Corrosion Rate Evolution in Concrete Structures with Hydrophobic Agents Exposed to the Marine Environment

2011 ◽  
Vol 374-377 ◽  
pp. 1320-1324
Author(s):  
Wei Qun Cao ◽  
Hong Fan ◽  
Tie Jun Zhao
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Marine Environment ◽  
Concrete Structures ◽  
Protective Layer ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Reinforced Concrete Structures ◽  
Chloride Diffusion Coefficient ◽  
Capillary Suction

In many cases, service life of reinforced concrete structures is severely limited by chloride penetration until the steel reinforcement. Today, concrete with high resistance with respect to chloride penetration can be produced by internal hydrophobic treatment. The aim of this study was to fill this gap in regards to reinforced concrete structures inserted in a marine environment. Results indicated the efficacy of the hydrophobic agents in cases where capillary suction is the mechanism of water penetration. However, when the transport mechanism is permeability this product is not advisable. Moreover, it was demonstrated that the chloride diffusion coefficient is reduced by the hydrophobic agents, and the corrosion rate of reinforcement could be well protected in the treated concrete with hydrophobic agents of silane. The durability of reinforced structures can be considerably increased and can be accurately designed by the application of an appropriate and optimized protective layer.

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