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.

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.

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

scholarly journals Multi-Stage Cold Forging Process for Manufacturing a High-Strength One-Body Input Shaft

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 532
Author(s):  
A Jo ◽  
Myeong Jeong ◽  
Sang Lee ◽  
Young Moon ◽  
Sun Hwang
Keyword(s):  
High Strength ◽  
Microstructural Characterization ◽  
Fatigue Tests ◽  
Machining Process ◽  
Cold Forging ◽  
Element Analysis ◽  
Forging Process ◽  
Input Shaft ◽  
Multi Stage ◽  
The One

A multi-stage cold forging process was developed and complemented with finite element analysis (FEA) to manufacture a high-strength one-body input shaft with a long length body and no separate parts. FEA showed that the one-body input shaft was manufactured without any defects or fractures. Experiments, such as tensile, hardness, torsion, and fatigue tests, and microstructural characterization, were performed to compare the properties of the input shaft produced by the proposed method with those produced using the machining process. The ultimate tensile strength showed a 50% increase and the torque showed a 100 Nm increase, confirming that the input shaft manufactured using the proposed process is superior to that processed using the machining process. Thus, this study provides a proof-of-concept for the design and development of a multi-stage cold forging process to manufacture a one-body input shaft with improved mechanical properties and material recovery rate.

High strength flowable lightweight concrete incorporating low C3A cement, silica fume, stalite and macro-polyfelin polymer fibres

2021 ◽  
Vol 281 ◽  
pp. 122410
Author(s):  
Huiyuan Liu ◽  
Mohamed Elchalakani ◽  
Ali Karrech ◽  
Sherif Yehia ◽  
Bo Yang
Keyword(s):  
Silica Fume ◽  
Lightweight Concrete ◽  
High Strength
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