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.

Effect of Stone Dust Content in Manufactured Sand on Chloride Diffusion Coefficient of Various Strength Grade Concretes

2011 ◽  
Vol 399-401 ◽  
pp. 1276-1281
Author(s):  
Peng Ping Li ◽  
Jian Bo Xiong ◽  
Zhi Hong Fan
Keyword(s):  
Diffusion Coefficient ◽  
Total Porosity ◽  
Immersion Test ◽  
Dust Content ◽  
Chloride Diffusion ◽  
Fine Aggregate ◽  
Chloride Diffusion Coefficient ◽  
Manufactured Sand ◽  
Stone Dust ◽  
Main Factor

The influence of stone dust content on chloride diffusion coefficient in C30, C40 and C50 grade concretes were investigated by means of the natural immersion test, XRD test, MIP test, SEM and TGA test, respectively. The experimental results showed that the chloride diffusion coefficient in C30 grade concretes decreased with increasing the stone dust content, but it decreased first and then increased with increasing the stone dust content in C40 and C50 grade concretes. The hydration degree for cementitious and compressive strength for concrete was slightly promoted by using stone dust replacing cementitious at a low level. For C30 grade concretes, the porosity decreased with increasing the stone dust content in fine aggregate, but for C40 and C50 grade concretes, the total porosity decreased first then increased with increasing the stone dust content. And the concrete pore structure was the main factor that influences the changes of chloride diffusion coefficient in concrete.

Influence of Stone Dust Content in Manufactured Sand on Chloride Diffusion Coefficient of C60 Grade Concrete

2011 ◽  
Vol 99-100 ◽  
pp. 749-753
Author(s):  
Peng Ping Li ◽  
Jian Bo Xiong ◽  
Zhi Hong Fan
Keyword(s):  
Diffusion Coefficient ◽  
Average Pore Size ◽  
Immersion Test ◽  
Dust Content ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Average Pore ◽  
Manufactured Sand ◽  
Stone Dust ◽  
Main Factor

The influence of stone dust content on chloride diffusion coefficient in C60 grade concrete were investigated by means of the natural immersion test, XRD test, MIP test and TGA test, respectively. The experimental results showed that the chloride diffusion coefficient increased with increasing the stone dust content in manufactured sand, and the chloride diffusion coefficient increased little when the stone dust content increasing from 7% to 13%. The hydration degree for cementitious and compressive strength for concrete was slightly promoted by using stone dust replacing cementitious at a low level. But the porosity and average pore size of concrete increased with increasing the stone dust content from 3% to 13%, and the concrete pore structure was the main factor that influences the changes of chloride diffusion coefficient in concrete.

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.

scholarly journals Chloride Resistance of Portland Cement-Based Mortar Incorporating High Aluminate Cement and Calcium Carbonate

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 359 ◽  
Author(s):  
Yunsu Lee ◽  
Seungmin Lim ◽  
Hanseung Lee
Keyword(s):  
Diffusion Coefficient ◽  
Calcium Carbonate ◽  
Pore Volume ◽  
Binding Capacity ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Binding ◽  
Chloride Resistance ◽  
Aluminate Cement ◽  
Capillary Pore

Whether chloride resistance is highly influenced by chloride binding capacity remains unknown. In this study, the chloride resistance of Portland cement-based mortar incorporating aluminate cement and calcium carbonate was investigated considering the chloride binding capacity, pore structures and chloride diffusion coefficient from non-steady state chloride migration and natural chloride diffusion. The cement hydrates were investigated using X-ray diffraction and thermogravimetric analysis. The chloride binding capacity was evaluated based on the chloride adsorption from the solutions using the adsorption isotherm. The aluminate cement, as an available alumina source, can stimulate the formulation of layered double hydroxides, which in turn can increase the chloride binding capacity. The results of mercury intrusion porosimetry show that non-substituted (control) and substituted (only aluminate cement) specimens have capillary pore volume 8.9 vol % and 8.2 vol %, respectively. However, the specimen substituted with aluminate cement and calcium carbonate shows a higher capillary volume (12.9 vol %), which correlates with the chloride diffusion coefficient. Although the specimen substituted with calcium carbonate has a higher chloride binding capacity than the control, it does not necessarily affect the decrease in the chloride diffusion coefficient. The capillary pore volume can affect not only the chloride diffusion but also the chloride adsorption.

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.

Correlation Test between Chloride Diffusion Coefficient and Microcosmic Pore Structure of Mineral Admixture Concrete

2013 ◽  
Vol 438-439 ◽  
pp. 81-86
Author(s):  
Yun Dong Zhu ◽  
Yang Li ◽  
Zhuo Zhao
Keyword(s):  
Diffusion Coefficient ◽  
Pore Structure ◽  
Nonlinear Regression ◽  
Mineral Admixture ◽  
Raw Material ◽  
Chloride Diffusion ◽  
Index Test ◽  
Chloride Diffusion Coefficient ◽  
Regression Relationship ◽  
Structure Index

Cube crushing strength, resistance to chloride penetration and gas adsorption analysis of mineral admixture concrete are tested to analyze the effect of raw material on chloride diffusion coefficient and its regression relationship with concrete microcosmic pore structure index. Test results show that chloride diffusion coefficient at different age increased with the increase of water-binding material ratio, decreased with the increase of cement dosage and both appeared a good nonlinear regression relationship. Chloride diffusion coefficient at different age increased with the increase of concrete microcosmic pore structure index. 56d chloride diffusion coefficient has a good linear correlation with microcosmic pore structure index, and 84d chloride diffusion coefficient has a good nonlinear regression relationship with microcosmic pore structure index.

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.

Research on Chloride Diffusion Model in Pre-Stressed Concrete with Sulfate Attack

2012 ◽  
Vol 166-169 ◽  
pp. 1935-1940
Author(s):  
Rong Gui Liu ◽  
Jing Li ◽  
Huan Li
Keyword(s):  
Diffusion Coefficient ◽  
Binding Capacity ◽  
Chloride Ion ◽  
Sulfate Attack ◽  
Ion Concentration ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Influence Of Water ◽  
Binder Ratio ◽  
Chloride Environment

Chloride diffusion coefficient is significant to the durability of pre-stressed concrete in chloride environment. The factors which influence chloride diffusion coefficient in pre-stressed concrete structures eroded by chloride ion is of great importance, including porosity, chloride ion binding capacity and the stress of pre-stressed concrete etc. Based on the Fick’s second law and existing models, the model of chloride ion diffusion in pre-stressed concrete with sulfate attack is established. It is analyzed that the influence of water-binder ratio and sulfate ion concentration and erosion time on concentration distribution of chloride ion in concrete. Compared to test data and project examples, it is confirmed that the model is useful.

scholarly journals Application of inverse methodology to estimation of chloride diffusion coefficient in concrete of prestressed precast slab

2018 ◽  
Vol 174 ◽  
pp. 01008
Author(s):  
Zofia Szweda ◽  
Zbigniew Buliński
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Equation ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Concrete Slabs ◽  
Chloride Diffusion Coefficient ◽  
Linear Diffusion ◽  
Estimated Parameters

Work presents an investigation of chloride penetration of HC-500 prestressed concrete slabs made of precast concrete. This type of concrete slabs is widely used to construct floors in steel or reinforced concrete framing buildings. In such solutions ceiling can be considered as a simple-supported beam. Considered precast concrete was made of C50/C60 concrete with use of Portland cement CEM II 52.5 R. Investigated specimens were sampled directly from the upper part of prestressed concrete slabs. The process of chloride penetration in concrete can be described by the non-linear diffusion equation. In the paper Bayesian inverse technique was applied to estimate diffusion coefficient of chloride in concrete treated as a saturated porous material. Unknown distribution of estimated parameters was sampled with use of Metropolis-Hastings algorithm which allowed us to obtain unknown values and their error bounds. Obtained values of diffusion coefficient were confronted against values obtained with use of norms: NT BUILD 443 and ASTM C 1556 - 03 and against previously developed methodology based on the analytical solution of the diffusion equation.

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