scholarly journals Influence of High Volume Fly Ash and Recycled Aggregates in Chloride and Carbonation Resistance of Concrete

2020 ◽  
Author(s):  
M. Etxeberria ◽  
F. Alvarez
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Recycled Aggregates ◽  
High Volume Fly Ash ◽  
Carbonation Resistance

Effects of Compressive Strength and Carbonation of HCSA Amount on High Volume Fly Ash Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 333-337
Author(s):  
Juan Hong Liu ◽  
Fang Fang Hou ◽  
Shao Min Song ◽  
Bo Ya Jia
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Internal Structure ◽  
High Volume ◽  
Carbonation Depth ◽  
Fly Ash Concrete ◽  
Resistance Increase ◽  
Expansive Concrete ◽  
High Volume Fly Ash ◽  
Carbonation Resistance

In this article, the effects of compressive strength and carbonation depth of HCSA mixing amount on high volume fly ash concrete have been investigated. Besides, the effects of compressive strength and carbonation depth of the fly ash amount on HCSA expansive concrete have been also analyzed. The results show that proper HCSA mixing amount can improve the compressive strength and anti-carbonation resistance. On the condition of 55% mixing amount of fly ash and 6% HCSA, the compressive strength for 28 days enhanced 8MPa, the carbonation depth decreased by 0.7mm, at the age of 70, the strength increased by 12MPa and the depth reduced 1.7mm; when the mixing amount of HCSA reaches 10%, the internal structure of concrete would be destroyed; In the case of 6% HCSA amount, the compressive strength and anti-carbonation resistance decreases with the increase of fly ash mixing amount. While comparing to the concrete without HCSA, the compressive strength and anti-carbonation resistance increase obviously.

scholarly journals Accelerated and natural carbonation of concrete with high volumes of fly ash: chemical, mineralogical and microstructural effects

2019 ◽  
Vol 6 (1) ◽  
pp. 181665 ◽  
Author(s):  
Philip Van den Heede ◽  
Mieke De Schepper ◽  
Nele De Belie
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Test Results ◽  
X Ray Diffraction ◽  
Carbonation Reaction ◽  
High Volume Fly Ash ◽  
Carbonation Resistance ◽  
Microstructural Effects ◽  
Natural Carbonation ◽  
Mineralogical Phases

Today, a rather poor carbonation resistance is being reported for high-volume fly ash (HVFA) binder systems. This conclusion is usually drawn from accelerated carbonation experiments conducted at CO 2 levels that highly exceed the natural atmospheric CO 2 concentration of 0.03–0.04%. However, such accelerated test conditions may change the chemistry of the carbonation reaction (and the resulting amount of CH and C–S–H carbonation), the nature of the mineralogical phases formed (stable calcite versus metastable vaterite, aragonite) and the resulting porosity and pore size distribution of the microstructure after carbonation. In this paper, these phenomena were studied on HVFA and fly ash + silica fume (FA + SF) pastes after exposure to 0.03–0.04%, 1% and 10% CO 2 using thermogravimetric analysis, quantitative X-ray diffraction and mercury intrusion porosimetry. It was found that none of these techniques unambiguously revealed the reason for significantly underestimating carbonation rates at 1% CO 2 from colorimetric carbonation test results obtained after exposure to 10% CO 2 that were implemented in a conversion formula that solely accounts for the differences in CO 2 concentration. Possibly, excess water production due to carbonation at too high CO 2 levels with a pore blocking effect and a diminished solubility for CO 2 plays an important role in this.

The Influence of Size Effect on High-Volume Fly-Ash Concrete’s Carbonation Resistance Performance

2011 ◽  
Vol 368-373 ◽  
pp. 1121-1124
Author(s):  
Li Fang Liu ◽  
Xiao Xia Niu ◽  
Wang Yu ◽  
Xiao Man Liu
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Size Effect ◽  
Blast Furnace Slag ◽  
High Volume ◽  
Carbonation Depth ◽  
Granulated Blast Furnace Slag ◽  
High Volume Fly Ash ◽  
Carbonation Resistance ◽  
Furnace Slag

using fixed concrete slump method,the carbonation resistance of concretes with high-volume fly-ash and ground granulated blast-furnace slag had been studied, and make an approach to size- effect .The results show that the more fly-ash joined in,the more carbonation depth is deeper . The carbonation resistance of concretes with high-volume fly-ash and ggbs is better than only with high-volume fly-ash’s. Size effect on carbonation depth of concretes is also important . Carbonation depth will become deeper as soon as the block size improving .and the early improvement is bigger than the late .The more concretes with high-volume fly-ash and ground granulated blast-furnace slag,the size-effect on carbonation depth of concretes will be more evident.

The Study on Workability and Mechanical Properties of High Volume Fly Ash Underwater Concrete

2014 ◽  
Vol 905 ◽  
pp. 235-238
Author(s):  
Xu Zhang ◽  
Qiao Ling Liu ◽  
Yu Qing Hu
Keyword(s):  
Fly Ash ◽  
High Performance ◽  
Fresh Concrete ◽  
High Volume ◽  
High Volume Fly Ash ◽  
Carbonation Resistance ◽  
Mineral Mixture ◽  
Underwater Concrete ◽  
Flocculating Agent ◽  
Early Strength

In this paper, in order to resolve contradiction that is between high workability and anti-segregation in fresh concrete, low early strength and poor carbonation resistance property of concrete and high volume fly ash addition, high performance water reducer is used to reduce yield stress in fresh concrete, mineral mixture and flocculating agent are used to adjust viscosity and measure of activation enhances early strength of this concrete.

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