scholarly journals Relating Rapid Chloride Migration Coefficient of Blast Furnace Slag Concrete to Capillary Pore Structure Parameters

2019 ◽  
Vol 278 ◽  
pp. 01007
Author(s):  
Chao Yang ◽  
Shuguang Wang ◽  
Feng Xu ◽  
Weiwei Li ◽  
Dongsheng Du
Keyword(s):  
Blast Furnace ◽  
Pore Structure ◽  
Blast Furnace Slag ◽  
Pore Radius ◽  
Structure Parameters ◽  
Capillary Porosity ◽  
Chloride Resistance ◽  
Chloride Migration ◽  
Furnace Slag ◽  
Capillary Pore

Blast furnace slag blended concrete is widely used in infrastructure, and its chloride resistance is of great concern. This paper experimentally investigated the capillary pore structure and chloride resistance of blast furnace slag blended concrete. Blast furnace slag was proved to be able to optimize the critical pore radius and decrease the proportion of detrimental capillary pores (with radius between 50 nm and 10,000 nm). Meanwhile, the benefit of BFS in improving the chloride resistance was proved. Finally, regression analysis showed that the rapid migration coefficient is proportional to the critical pore radius and the detrimental capillary pore proportion. Nevertheless, the rapid migration coefficient is not closely related to the capillary porosity.

The Porosity and Pore Structure of Hydrated Cement Pastes as Revealed by Electron Micrsocopy Techniques

1988 ◽  
Vol 137 ◽  
Author(s):  
Ian G. Richardson ◽  
Geoffrey W. Groves ◽  
Sally A. Rodger
Keyword(s):  
Blast Furnace ◽  
Electron Microscope ◽  
Pore Structure ◽  
Blast Furnace Slag ◽  
Cement Hydration ◽  
Mercury Porosimetry ◽  
Hydrated Cement ◽  
Cement Pastes ◽  
Transmission Electron ◽  
Furnace Slag

AbstractThe application of transmission electron microscope techniques to the study of cement hydration can reveal the nature of the fine pore structure present in dried cement pastes. Studies of OPC cement pastes and OPC/fly ash or blast-furnace slag blends are presented and compared. Preliminary results of a technique which allows effective imaging of the porosity which is important in permeation, and which is involved in mercury porosimetry measurements, are presented.

Relation Between Strength, Pore Structure and Associated Properties of Slag-Containing Cementitious Materials

1984 ◽  
Vol 42 ◽  
Author(s):  
Della M. Roy ◽  
G. M. Idorn
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Pore Structure ◽  
Cement Paste ◽  
Blast Furnace Slag ◽  
Cementitious Materials ◽  
Granulated Blast Furnace Slag ◽  
Pore Structures ◽  
Furnace Slag

AbstractSubstantial increases of the strength of cement paste and mortars may be obtained in conventional processing by optimizing the materials components, the rheology and the curing, and thereby improving the microstructures. Cementitious materials with high proportions of granulated blast-furnace slag have been investigated. Higher strengths of ASTM C 109 mortars were obtained with 40 to 65% substitution of portland cement by slag, than with ordinary mix compositions and processing.For one set of mixtures, 28 day strengths ≥ 100 MPa (some as high as 240 MPa) were consistently attained after curing at temperatures ranging from 27 to 250°C. The slag substitutions developed finer pore structures as revealed by intrusion porosimetry measurements, than those with pure portland cement. This is believed to be a major reason for their enhanced durability. At each stage from 3 to 28 days, increase of curing temperatures from 27 to 90°C decreased porosity and increased the strength, reflecting an increased maturity.Implications for practice and suggestions for further work are discussed.

scholarly journals Effect of Blast-Furnace Slag Replacement Ratio and Curing Method on Pore Structure Change after Carbonation on Cement Paste

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4787
Author(s):  
Junho Kim ◽  
Seunghyun Na ◽  
Yukio Hama
Keyword(s):  
Blast Furnace ◽  
Calcium Carbonate ◽  
Pore Structure ◽  
Calcium Silicate ◽  
Blast Furnace Slag ◽  
Calcium Silicate Hydrate ◽  
Structure Change ◽  
Replacement Rate ◽  
Replacement Ratio ◽  
Furnace Slag

The frost damage resistance of blast-furnace slag (BFS) cement is affected by carbonation. Hence, this study investigates the carbonation properties of pastes incorporating BFS with different replacement ratios, such as 15%, 45%, and 65% by weight, and different curing conditions, including air and carbonation. The BFS replacement ratio properties, determined by the Ca/Si ratio of calcium silicate hydrate in the cement paste sample, were experimentally investigated using mercury intrusion porosimetry, X-ray diffraction, and thermal analysis. The experimental investigation of the pore structure revealed that total porosity decreased after carbonation. In addition, the porosity decreased at a higher rate as the BFS replacement rate increased. Results obtained from this study show that the chemical change led to the higher replacement rate of BFS, which produced a higher amount of vaterite. In addition, the lower the Ca/Si ratio, the higher the amount of calcium carbonate originating from calcium silicate hydrate rather than from calcium hydroxide. As a result of the pore structure change, the number of ink-bottle pores was remarkably reduced by carbonation. Comparing the pore structure change in air-cured and carbonation test specimens, it was found that as the replacement rate of BFS increased, the number of pores with a diameter of 100 nm or more also increased. The higher the replacement rate of BFS, the higher the amount of calcium carbonate produced compared with the amount of calcium hydroxide produced during water curing. Due to the generation of calcium carbonate and the change in pores, the overall number of pores decreased as the amount of calcium carbonate increased.

scholarly journals Performance Evaluation of Cementitious Composites Containing Granulated Rubber Wastes, Silica Fume, and Blast Furnace Slag

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 632
Author(s):  
Maléki Tagba ◽  
Shujin Li ◽  
Mingjie Jiang ◽  
Xu Gao ◽  
Mohamed Larbi Benmalek ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Microstructural Analysis ◽  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Fine Aggregate ◽  
Chloride Resistance ◽  
Accessible Porosity ◽  
Furnace Slag

In this study, rubberized cementitious materials are produced with recycled rubber waste as an alternative to fine aggregate. Mixtures with different additions to rubber wastes (RW), silica fume (SF), and blast furnace slag (BFS) have been designed and characterized. Hardened properties including compressive and bond strength, shrinkage, water-accessible porosity, rapid chloride migration, and microstructure were investigated. The results show that the addition of SF and BFS improves the performances of rubberized mortars and reduces shrinkage. The incorporation of 5% RW with 20% BFS increases compressive strength and reduces water-accessible porosity. Ion chloride resistance was enhanced by a combination of 15% RW, 8% SF, and 20% BFS. The addition of SF and BFS as cement replacement improves the performance of mortars due to their filling effect and a pozzolanic reaction, which has been verified by a microstructural analysis.

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