scholarly journals Activation of Blast Furnace Slag with CFB Fly Ash as a Supplementary Binder Material: Hydration Products and Effects of Sulfate Attack

Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 41
Author(s):  
Guan-Yu Chen ◽  
Wei-Hsing Huang
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Sulfate Attack ◽  
Gravimetric Analysis ◽  
Hydration Products ◽  
Hydrated Calcium Silicate ◽  
Volume Stability ◽  
Binder Material ◽  
Furnace Slag

Circulating Fluidized Bed (CFB) combustion is a clean technology for burning, with advantages of adapting to a large variety of fuel, high combustion efficiency, lower NOx emissions, and stable operation. The residue collected from the ash-hoppers of the electrostatic precipitator of the CFB boiler is called CFB fly ash. This paper presents the hydration development on the application of CFB fly ash to activating blast furnace slag (BFS) as a supplementary binder material (SBM) for replacement of Portland cement in making concrete. Investigation of the hydration products of cement pastes prepared with combinations of BFS and CFB fly ash were conducted by means of X-ray diffraction, thermal gravimetric analysis, and scanning electronic microscope. Test results show that the main hydration products of the CFB fly ash-BFS blended pastes were found to be hydrated calcium silicate (C-S-H), ettringite, gypsum, and some portlandite. Considering that CFB fly ash produced from the combustion of high-sulfur coke has high SO3 contents, the volume stability of mortar made from CFB fly ash-activated BFS was subjected to tests in accordance with ASTM C1012 and ASTM C1038 for evaluating the internal and external sulfate attack, respectively. The results indicate that, due to the high sulfur (SO3) content of CFB fly ash, the expansion caused by internal sulfate attack (ISA) increased with increasing proportion of CFB fly ash in the mixture. In contrast, no significant expansion was observed in the external sulfate attack (ESA) test, regardless of the proportion of CFB fly ash in the mixture. In order for the CFB fly ash to serve as a supplementary binder material and to maintain adequate volume stability, the amount of CFB fly ash used for the activation of BFS is recommended to be no more than 20% of the SBM.

Optimization of Concrete Porous Mix Using Slag as Substitute Material for Cement and Aggregates

2017 ◽  
Vol 865 ◽  
pp. 282-288 ◽  
Author(s):  
Jul Endawati ◽  
Rochaeti ◽  
R. Utami
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Environmental Effect ◽  
Substitution Effect ◽  
Main Concern ◽  
Binder Material ◽  
Furnace Slag

In recent years, sustainability and environmental effect of concrete became the main concern. Substituting cement with the other cementitious material without decreasing mechanical properties of a mixture could save energy, reduce greenhouse effect due to mining, calcination and limestone refining. Therefore, some industrial by-products such as fly ash, silica fume, and Ground Iron Blast Furnace Slag (GIBFS) would be used in this study to substitute cement and aggregate. This substitution would be applied on the porous concrete mixture to minimize the environmental effect. Slag performance will be optimized by trying out variations of fly ash, silica fume, and slag as cement substitution material in mortar mixture. The result is narrowed into two types of substitution. First, reviewed from the fly ash substitution effect on binder material, highest compressive strength 16.2 MPa was obtained from mixture composition 6% fly ash, 3% silica fume and 17% grinding granular blast-furnace slag. Second, reviewed from slag types as cement substitution and silica fume substitution, highest compressive strength 15.2 MPa was obtained from mortar specimens with air-cooled blast furnace slag. It composed with binder material 56% Portland composite cement, 15% fly ash, 3% silica fume and 26% air-cooled blast furnace slag. Considering the cement substitution, the latter mixture was chosen.

Study on Sulfate Resistance of Concrete with Compound Mineral Admixture

2011 ◽  
Vol 99-100 ◽  
pp. 420-425 ◽  
Author(s):  
Qian Rong Yang ◽  
Xiao Qian Wang ◽  
Hui Ji
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Sulfate Attack ◽  
Mineral Admixture ◽  
Sulfate Resistance ◽  
Chemical Attack ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

The strength, expansion and amount of scaling of concrete with compound mineral admixture (CMA) from steel slag, granulated blast furnace slag and fly ash were studied. The result shows that damage by crystallization press from sulfate attack when concrete was exposed to sulfate environments under wetting–drying alternation is much larger than that from sulfate chemical attack. Adding CMA to concrete could reduce the damage from expansion of concrete caused by sulfate chemical attack, but the resistance of concrete to damage by crystallization press from sulfate attack was remarkably reduced.

External sulfate attack on alkali-activated fly ash-blast furnace slag composite

2017 ◽  
Vol 157 ◽  
pp. 737-747 ◽  
Author(s):  
N. Džunuzović ◽  
M. Komljenović ◽  
V. Nikolić ◽  
T. Ivanović
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Sulfate Attack ◽  
Furnace Slag ◽  
Alkali Activated

Research on Properties and Reaction Mechanism of Blast Furnace Slag Backfilling Cementing Material

2014 ◽  
Vol 692 ◽  
pp. 454-459
Author(s):  
Shu Gang Hu ◽  
Xian Jun Lu ◽  
Hai Li Niu
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Xrd Analysis ◽  
Hydration Products ◽  
Hydrated Calcium Silicate ◽  
Products Analysis ◽  
Cementing Material ◽  
Furnace Slag ◽  
Hydrated Calcium ◽  
Amorphous Substances

According to XRD, DTA and SEM detections, the hydration products of blast furnace slag based cementing material SL, SLG. were studied in different age periods. The XRD analysis of cementing material SL hydration products showed the composition of hydration products were mainly amorphous substances, few crystalline substances. Characteristic peak of ettringite, such as AFt, hadn’t been found in the spectral line of DTA, and it hadn’t been found in the figures of SEM, either, which was accordant with the conclusion that the cementing performance of SL mainly coming from gel of hydrated calcium silicate (CSH) and hydrated calcium aluminate. But the cementing performance of SLG mainly coming from Aft, CSH and AFm from hydration products analysis of different age periods.

Investigation on Blending CFB Ash with Blast Furnace Slag as Replacement for Portland Cement Used in Concrete Binders

2013 ◽  
Vol 723 ◽  
pp. 623-629 ◽  
Author(s):  
Guan Yu Chen ◽  
Wei Hsing Huang
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Petroleum Coke ◽  
Blast Furnace Slag ◽  
Circulating Fluidized Bed ◽  
Slag System ◽  
Ash Content ◽  
Chemical Compositions ◽  
Volume Stability ◽  
Furnace Slag

Circulating Fluidized Bed (CFB) Boiler is a means of energy-generating process by burning petroleum coke. In order to avoid blazed petroleum coke with high sulfur content from emitting overdosed sulfur dioxide, limestone is introduced in the boiler for desulfuration. The residue collected from the boiler is called CFB ash. In accordance with different boiler position, CFB ashes can be classified as fly ash and bed ash, and both have similar chemical compositions, with high contents of gypsum and calcium oxide. In this study, CFB ash (fly ash) is mixed with blast furnace slag (BFS) as a substitute for cement in making concrete. It is intended that CFB ashes can be used in concrete and a method for proportioning CFB ash in concrete can be developed. The results show that CFB ash can react with cement to produce hydration products such as Ca(OH)2, and bring the activation of blast furnace slag. The paste strength could be low at later ages, if the CFB ash content is too low. Whereas, if the CFB ash content is over 30%, the paste strength will be low at the early age. Therefore, it is concluded that the cement-granulated blast furnace slag system will show best performance at the CFB ash content between 18% and 22%. In autoclave soundness test shows the CFB ash of the high f-CaO content is easy reaction in the water, and also did not negatively affect the quality of the volume stability.

Influence of Compounded Mineral Admixtures on Shrinkage and Early-Age Cracking Behaviors of Concrete

2012 ◽  
Vol 450-451 ◽  
pp. 738-742
Author(s):  
Xue Fang Wang ◽  
Jian Lan Zheng
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Synergistic Effect ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Early Age ◽  
Volume Stability ◽  
Furnace Slag

Influence of compounded mineral admixtures on shrinkage and early-age cracking behaviors of concrete was studied, based on the fellow factors: fly ash to blast furnace slag(denoted as BSF) ratio, fly ash-metakaolin ratio, BSF-silica fume ratio. Research shows that the Pozzolanic admixtures compounded with cementitious admixtures have complementary and synergistic effect for hydration progress of concrete, which can enhance the volume stability and cracking behaviors of concrete. However, the pozzolanic admixture compounded with other pozzolanic admixture, two pozzolanic admixtures will grab Ca(OH)2 resource. And then if the dosage of mineral admixture is higher, the compounding will result to decrease the volume stability and cracking behaviors of concrete.

scholarly journals Application of fly ash/granulated blast-furnace slag cementing material for immobilization of Pb2+

2018 ◽  
Vol 175 ◽  
pp. 01020 ◽  
Author(s):  
Li Chao ◽  
Zhao Feng-qing
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Low Cost ◽  
Hydration Products ◽  
Experimental Conditions ◽  
Granulated Blast Furnace Slag ◽  
Carbide Slag ◽  
Cementing Material ◽  
Furnace Slag

Based on activation and synergistic effect among various materials, a low-cost cementing material. FGC binder, was prepared by using fly ash. granulated blast-furnace slag (BFS). carbide slag and compound activator. The results showed that the immobilization efficiency of FGC binder for Pb2+: is higher than that of OPC cement. The hydration products and mechanism of immobilization were analyzed by using XRD. The major products of FGC binder are C-S-H, C-A-H. ettringite and zeolite-like materials. Under the experimental conditions, the Pb2+ curing efficiency of FGC binder is 1.04 ~ 1.24 times that of ordinary Portland cement.

scholarly journals Effect of Mineral Admixtures on the Performance of Low-Quality Recycled Aggregate Concrete

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 596
Author(s):  
Yasuhiro Dosho
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Mineral Admixtures ◽  
Structural Concrete ◽  
Aggregate Concrete ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

To improve the application of low-quality aggregates in structural concrete, this study investigated the effect of multi-purpose mineral admixtures, such as fly ash and ground granulated blast-furnace slag, on the performance of concrete. Accordingly, the primary performance of low-quality recycled aggregate concrete could be improved by varying the replacement ratio of the recycled aggregate and using appropriate mineral admixtures such as fly ash and ground granulated blast-furnace slag. The results show the potential for the use of low-quality aggregate in structural concrete.

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