Influence of Permeability of HCSA Expansive Agent on High Volume Fly Ash Concrete

2011 ◽  
Vol 477 ◽  
pp. 354-358 ◽  
Author(s):  
Fang Fang Hou ◽  
Juan Hong Liu
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Rapid Determination ◽  
High Volume ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Experimental Conditions ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Expansive Agent

Based on the rapid determination of chloride diffusion coefficient with NEL method and pore structure analysis, the influence of HCSA expansive agent on chloride diffusion coefficient of concrete has been investigated. Besides, the effects of chloride diffusion coefficient of Water-Cement ratio on HCSA expansive concrete have been also analyzed. The results show that on the condition of 55% mixing amount of fly ash, the chloride diffusion coefficient of concrete of no HCSA is 1.96×10－8cm2/s, which is classified moderate. While the concrete mixing HCSA is about 0.62×10－8cm2/s, the permeability belongs to inferior. The effects of permeability of HCSA mixing amount on concrete is not obviously. The Water-Cement ratio affects the concrete permeability. Under the experimental conditions, the water-cement ratio of 0.4 can achieve better effect of the HCSA expansion; Furthermore, the mercury intrusion further verified that incorporating proper amount of HCSA can make the internal structure dense and improve the density and impermeability of concrete.

Experimental Study and Numerical Analysis on Chloride Diffusion Coefficient of Concrete with Various Water-Cement Ratios

2017 ◽  
Vol 726 ◽  
pp. 547-552
Author(s):  
Zheng Ren ◽  
Lian Zhen Xiao ◽  
Wen Chong Shi
Keyword(s):  
Diffusion Coefficient ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Ion Diffusion ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Influence Of Water ◽  
Chloride Ion Diffusion

A rapid chloride ion diffusion coefficient measurement (RCM) was used in this study. The influence of water-cement ratios of 0.30, 0.35 and 0.40 at various ages (3, 7, 14, 28 and 56 days) on chloride ion diffusion coefficient of the concretes and pastes was studied and analyzed. The results show that, with the increase of curing ages, the chloride ion diffusion coefficient of different water-cement ratio of each specimen is decreased. In the early age, the chloride ion diffusion coefficient of the paste with the water-cement ratio of 0.40 is 2~3 times of the paste with water-cement ratio of 0.30 and 0.35, and with the increase of curing age, this difference is gradually decreased. Additionally, the chloride ion diffusion coefficient of the cement paste is 1~2 times of the concrete with same water-cement ratio at different ages. Based on the actual experiment boundary conditions, the process of chloride ions diffusion and permeability was simulated by COMSOL software, and the simulation result was analyzed to predict the permeability of 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.

Effect of Coarse Aggregate Types on the Microstructure of the ITZ and Durability of Concrete

2013 ◽  
Vol 838-841 ◽  
pp. 1801-1805 ◽  
Author(s):  
Li Juan Kong ◽  
Qing Chao Meng ◽  
Yuan Bo Du
Keyword(s):  
Rough Surface ◽  
Coarse Aggregate ◽  
High Water ◽  
Chloride Diffusion ◽  
Concrete Durability ◽  
Chloride Diffusion Coefficient ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Limestone Aggregate

Influence of aggregate types on the impermeability and frost-resistance of concrete with different water/cement ratios were investigated, as well as the pore structure and hydrates of the ITZ. The results show that, concrete prepared with a high water/cement ratio and using granite aggregate, presents the highest values of chloride diffusion coefficient and the lowest numbers of freeze-thaw cycles. Whereas concrete prepared with a low water/cement ratio and using limestone aggregate, obtains the similar durability results. The limestone aggregate with a rough surface and higher water absorption, has a tight bonding with the cement paste. However, the granite and basalt aggregate that formed by magma eruption, have higher activity. The XRD results demonstrate that more clinkers participate in the hydration of cement, therefore, resulting in a denser ITZ. In order to improve the concrete durability, the basalt aggregate both with higher activity and rough surface is consider optimal.

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 Engineering Properties of Ternary Cementless Blended Materials

2020 ◽  
Vol 10 (3) ◽  
pp. 191-199
Author(s):  
Wei-Ting Lin ◽  
Kinga Korniejenko ◽  
Marek Hebda ◽  
Michał Łach ◽  
Janusz Mikuła
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Engineering Properties ◽  
Chloride Diffusion ◽  
Total Charge ◽  
Chloride Diffusion Coefficient ◽  
Furnace Slag

A new non-cement blended materials is developed as a full replacement of cement without alkali activator. This study was conducted to explore a suitable method for activating new ternary green materials with desulfurization gypsum, water-quenched blast-furnace slag and co-fired fly ash from circulating fluidized bed combustion as non-cement inorganic binder. Test subject was included flowability, compressive strength, absorption, total charge-passed from rapid chloride permeability test, chloride diffusion coefficient from accelerated chloride migration test and SEM observation. Test results indicate that a ternary mixture containing 1% desulfurization gypsum, 60% water-quenched blast-furnace slag and 39% co-fired fly ash was a suitable development in compressive strength. The new non-cement blended materials were performed a well compressive strength, lower absorption, and lower chloride diffusion coefficient. In addition, the compressive strength decreased as the inclusion of desulfurization gypsum increased. It was concluded that using desulfurization gypsum alone decreased the setting time and compressive strength. SEM micrographs were verified the development in compressive strength originated from the C-S-H and C-A-S-H gel produced by Ca(OH)2, SiO2, and Al2O3.

Influence of Mineral Admixtures on Chloride Diffusion Coefficient of Self-Compacting Concrete

2013 ◽  
Vol 405-408 ◽  
pp. 2876-2880
Author(s):  
Jian Bo Xiong ◽  
Peng Ping Li ◽  
Sheng Nian Wang
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Cementitious Materials ◽  
Ash Content ◽  
Mineral Admixtures ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Self Compacting Concrete ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

The influence of mineral admixtures on workability of fresh concrete and chloride ion permeability resistance of hardened concrete for C50 self-compacting concrete was investigated by means of the Natural Immersion Test. The results showed that the chloride diffusion coefficient in fly ash concrete decreased first and then increased with increasing fly ash content in cementitious materials, when fly ash content was 30% or 40%, it got the lowest value at 28 days or 90 days, respectively. The chloride diffusion coefficient in specimens decreased with increasing the ground granulated blast furnace slag content in cementitious materials, but it changed little when the replacement was in ranges of 50% to 60%. Furthermore, for the specimens which replaced by fly ash and ground granulated blast furnace slag, the chloride diffusion coefficient decreased first and then increased with increasing the fly ash content in complex cementitious, and when fly ash content was 10% or 20%, it got the lowest value at 28 days or 90 days, respectively.

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