Effect of fly ash and silica fume on transition zone, pore structure and permeability of concrete

2018 ◽  
Vol 70 (10) ◽  
pp. 519-532 ◽  
Author(s):  
Ali Sadrmomtazi ◽  
Behzad Tahmouresi ◽  
Reza Kohani Khoshkbijari
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Transition Zone ◽  
Silica Fume

The Contribution of the Transition Zone to the Strength of High Quality Silica Fume Concretes

1987 ◽  
Vol 114 ◽  
Author(s):  
A. Bentur ◽  
A. Goldman ◽  
M. D. Cohen
Keyword(s):  
Pore Structure ◽  
Transition Zone ◽  
Silica Fume ◽  
Fresh Concrete ◽  
High Strength ◽  
High Quality ◽  
The One

ABSTRACTThe strength of high strength silica fume concretes is usually attributed to the reduction in w/c ratio and the refinement of the pore structure. A study of concretes and pastes, with and without silica fume, suggests that the contribution of the silica fume to strength is also the result of the densification of the transition zone. It is argued here that this influence is as important as the one due to the reduction in w/c ratio. It is suggested that the densification of the transition zone is the result of the effect of the silica fume on the nature of the fresh concrete.

Quantitative evaluation of mineral admixtures on the properties, pore structure, and durability of cement-based composites

2012 ◽  
Vol 19 (2) ◽  
pp. 199-207 ◽  
Author(s):  
Chinlai Lee ◽  
Maochieh Chi ◽  
Ran Huang
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Silica Fume ◽  
Mercury Intrusion Porosimetry ◽  
Cementitious Material ◽  
Mineral Admixtures ◽  
Penetration Test ◽  
Compressive Strength Test ◽  
Testing Data ◽  
Influence Of Water

AbstractThe influence of water/cementitious material ratio, silica fume, and fly ash as partial Portland cement replacement materials on the properties, pore structure, and durability of cement-based composites was evaluated by conducting compressive strength test, mercury intrusion porosimetry test, water absorption, rapid chloride penetration test, and scanning electron microscopy (SEM). Water/cementitious material ratio, and replacement percentage of silica fume and fly ash have significant effects on the pore structure and durability of cement-based composites. Composites with silica fume or fly ash have a denser structure than the control composite on SEM micrographs. Silica fume has about 5–10 times as much effect as fly ash, according to results of multiple linear regression analyses of testing data.

Study on Ultra-Strength Mortar Prepared with Mineral Admixture

2011 ◽  
Vol 675-677 ◽  
pp. 1073-1076
Author(s):  
Zu Quan Jin ◽  
Peng Zhang ◽  
Tie Jun Zhao ◽  
Bao Rong Hou
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Pore Structure ◽  
Silica Fume ◽  
Mineral Admixture ◽  
Replacement Rate ◽  
River Sand ◽  
Optimum Proportion ◽  
Curing Age

In this paper, preparation, property study of ultra-strength mortars with mineral admixture and clear river sand was carried out. The mineral admixture include fly ash, ultra-fine GGBS and silica fume. The experimental results show that the compressive strength of mortar improves with increasing amount of silica fume or ultra-fine GGBS. When the content of silica fume or ultra-fine GGBS is 30~35%, the compressive strength and flexural strength of mortar in curing age of 7 days are 100 MPa and 20MPa, respectively. But strength of mortar decreases with the increase replacement rate of fly ash. When the mortar mixes with combined of silica fume and ultra-fine GGBS, the optimum proportion of siliaca fume to ultra-fine GGBS is 2:3. And the compressive strength of mortar in curing age of 7 days is 75~100MPa when the mixed mineral admixture is 40~60%. The compressive strength of mortar is about 90MPa as it mix 60% of cement, 15% of silica fume, 15% of GGBS and 10% of fly ash. Moreover, the ultra strength mortar refines its pore structure and its capiliary pore (≥100nm) amount reduces by 78% compared to ordinary mortar.

Influence of Mineral Admixtures on Crack Resistance of High Strength Concrete

2006 ◽  
Vol 302-303 ◽  
pp. 150-154 ◽  
Author(s):  
Shu Hua Liu ◽  
Kun He Fang ◽  
Zeng Li
Keyword(s):  
Fly Ash ◽  
Crack Resistance ◽  
Transition Zone ◽  
Silica Fume ◽  
High Strength Concrete ◽  
High Strength ◽  
Mineral Admixtures ◽  
Mechanism Analysis ◽  
Strength Concrete ◽  
Concrete Crack

As high strength concrete (HSC) is widely used in construction, more and more attention has been paid to crack resistance of it. In order to improve crack resistance of HSC, we study the influence of mineral admixtures (ground slag, silica fume and fly ash) on brittleness and characteristic length as crack resistance’ indexes. Testing researches shows, without admixture, crack resistance of HSC is the lowest; when one of the three mineral admixtures added, crack resistance increases dramatically; when two of the three mineral admixtures are added in the concrete, crack resistance increases a little more and it does not change very much no matter which two are mixed; crack resistance comes out the highest when the three mineral admixtures are added in concrete. Mechanism analysis shows, Adding fine and high active ground slag, silica fume and fly ash into concrete can greatly improve microstructure of transition zone, decrease Ca(OH)2, ettringite and porosity in concrete, increase C-S-H gel and greatly reduce the original micro-cracks in the transition zone.

Microstructure of High Strength Concrete Mercury Intrusion Porosimetry and Thermogravimetry Analysis

2011 ◽  
Vol 243-249 ◽  
pp. 3781-3786 ◽  
Author(s):  
Iqbal Khan Mohammad
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Calcium Hydroxide ◽  
Silica Fume ◽  
High Strength Concrete ◽  
Mercury Intrusion Porosimetry ◽  
High Strength ◽  
Thermogravimetry Analysis ◽  
Mercury Intrusion ◽  
Strength Concrete

Microstructural properties such as pore structure and hydration play a decisive role in determining the properties of a concrete. This paper presents the investigation on pore structure and hydration process of high strength concrete. Pore structure study was conducted using mercury intrusion porosimetry and hydration progress was monitored using thermogravimetry analysis on various blended combinations of cementitious materials incorporating fly ash and silica fume as partial cement replacement. It was found that silica fume refined the pore structure efficiently and reduced the calcium hydroxide content as early as 1 day. All ternary blended systems containing fly ash and silica fume exhibited lower calcium hydroxide content and refined pore structure in comparison to their respective blended pastes.

COMPRESSIVE STRENGTH AND THERMAL CONDUCTIVITY OF WATER AND AIR CURED PORTLAND CEMENT-FLY ASH-SILICA FUME MORTARS

2018 ◽  
Vol 17 (9) ◽  
pp. 2023-2030
Author(s):  
Arnon Chaipanich ◽  
Chalermphan Narattha ◽  
Watcharapong Wongkeo ◽  
Pailyn Thongsanitgarn
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume
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