scholarly journals Optimizing the Acid Resistance of Concrete with Granulated Blast-Furnace Slag

2018 ◽  
Vol 199 ◽  
pp. 02001
Author(s):  
Rolf Breitenbücher ◽  
Jan Bäcker ◽  
Sebastian Kunz ◽  
Andreas Ehrenberg ◽  
Christian Gerten
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Acid Resistance ◽  
Industrial Applications ◽  
Acid Attack ◽  
Dense Microstructure ◽  
Granulated Blast Furnace Slag ◽  
Acid Type ◽  
The Matrix ◽  
Furnace Slag

Concrete for agricultural or industrial applications is often subject to intense acid attack. Most affected structures are sewage structures and biogas plants, natural draught cooling towers or silage silos. Widely independent from acid type, in most cases the acid attack on concrete runs the same way, starting with dissolution of easily soluble calcareous phases like calcium hydroxide. With ongoing attack, calcium-silicate-hydrate crystals (CSH) are also affected by acidic media. In contrast, siliceous phases like silicon-dioxide (SiO2) are widely unaffected by acid attack. While the dissolution of the matrix is increasing with ongoing attack, quarzitic aggregates remain unchanged. Beside the use of coarse SiO2-aggregates, the resistance against acid attack is mainly increased by a minimization of the porosity. For this purpose on one hand, a low water/cement-ratio has to be sought, on the other hand also the fines should be distributed with an optimized grading curve (e.g. Fuller-principle). In practice, this results in a combination of various fine and ultra-fine components, e.g. fly ash, GGBS, silica fume or metakaolin. Such binder compositions lead to a particularly dense microstructure, especially at pore sizes below 1 micron, and a higher chemical resistance due to a lower Ca(OH)2 content. This paper gives an overview on typical acid-resistant concretes, most common applications as well as the effects of the related acid attack and points out the potential of granulated blast furnace slag addition to such concretes.

Pretreatment of Tc-Containing Waste and Its Effect on Tc-99 Leaching from Grouts

2006 ◽  
Vol 985 ◽  
Author(s):  
Albert Aloy ◽  
Elena N Kovarskaya ◽  
John R. Harbour ◽  
Christine A. Langton ◽  
E William Holtzscheiter
Keyword(s):  
Blast Furnace ◽  
Salt Solution ◽  
Blast Furnace Slag ◽  
Transport Model ◽  
Effective Diffusion ◽  
Granulated Blast Furnace Slag ◽  
Waste Forms ◽  
Iron Salts ◽  
The Matrix ◽  
Furnace Slag

AbstractA salt solution (doped with Tc-99), that simulates the salt waste stream to be processed at the Saltstone Production Facility, was immobilized in grout waste forms with and without (1) ground granulated blast furnace slag and (2) pretreatment with iron salts. The degree of immobilization of Tc-99 was measured through monolithic and crushed grout leaching tests. Although Fe (+2) was shown to be effective in reducing Tc-99 to the +4 state, the strong reducing nature of the blast furnace slag present in the grout formulation dominated the reduction of Tc-99 in the cured grouts. An effective diffusion coefficient of 4.75 x 10-12 (Leach Index of 11.4) was measured using the ANSI/ANS-16.1 protocol. The leaching results show that, even in the presence of a concentrated salt solution, blast furnace slag can effectively reduce pertechnetate to the immobile +4 oxidation state. The measured diffusivity was introduced into a flow and transport model (PORFLOW) to calculate the release of Tc-99 from a Saltstone Vault as a function of hydraulic conductivity of the matrix.

Effect of Fly Ash and Ground Granulated Blast-Furnace Slag on Sulfuric Acid Resistance of Concrete

2011 ◽  
Vol 243-249 ◽  
pp. 1860-1865
Author(s):  
Bei Xing Li ◽  
Kai Yang ◽  
Jiang Liu ◽  
Ming Kai Zhou
Keyword(s):  
Blast Furnace ◽  
Sulfuric Acid ◽  
Fly Ash ◽  
Cement Paste ◽  
Blast Furnace Slag ◽  
Acid Resistance ◽  
Basic Reason ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

The effect of Fly ash (FA) and ground granulated blast-furnace slag (GGBS) on sulfuric acid resistance of concrete has been investigated in this study. Cement was replaced by FA with the incorporation amount from 20% to 50% or by GGBS from 35% to 65%. Results indicate that with an increase in fly ash replacement amount, the sulfuric acid resistance of concrete was improved. Sulfuric acid resistance of concrete with GGBS was improved only when the replacement amount of GGBS exceeds 50%. The basic reason for deterioration of concrete in sulfuric acid is the degradation of C-S-H gel in matrix. Increasing the content of SiO2 in cement paste can improve the acid resistance of concrete.

The Influence of the Properties of the Material Used for Obtaining Geopolymers on Their Structure and Compressive Strength

2017 ◽  
Vol 68 (6) ◽  
pp. 1182-1187
Author(s):  
Ilenuta Severin ◽  
Maria Vlad
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Wheat Straw ◽  
Red Mud ◽  
Blast Furnace Slag ◽  
Complex Structure ◽  
Point Of View ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag ◽  
Straw Ash

This article presents the influence of the properties of the materials in the geopolymeric mixture, ground granulated blast furnace slag (GGBFS) + wheat straw ash (WSA) + uncalcined red mud (RMu), and ground granulated blast furnace slag + wheat straw ash + calcined red mud (RMc), over the microstructure and mechanical properties of the synthesised geopolymers. The activation solutions used were a NaOH solution with 8M concentration, and a solution realised from 50%wt NaOH and 50%wt Na2SiO3. The samples were analysed: from the microstructural point of view through SEM microscopy; the chemical composition was determined through EDX analysis; and the compressive strength tests was done for samples tested at 7 and 28 days, respectively. The SEM micrographies of the geopolymers have highlighted a complex structure and an variable compressive strength. Compressive strength varied from 24 MPa in the case of the same recipe obtained from 70% of GGBFS + 25% WSA +5% RMu, alkaline activated with NaOH 8M (7 days testing) to 85 MPa in the case of the recipe but replacing RMu with RMc with calcined red mud, alkaline activated with the 50%wt NaOH and 50%wt Na2SiO3 solution (28 days testing). This variation in the sense of the rise in compressive strength can be attributed to the difference in reactivity of the materials used in the recipes, the curing period, the geopolymers structure, and the presence of a lower or higher rate of pores, as well as the alkalinity and the nature of the activation solutions used.

scholarly journals Effect of Flue Gas Desulfurization Gypsum on the Properties of Calcium Sulfoaluminate Cement Blended with Ground Granulated Blast Furnace Slag

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 382 ◽  
Author(s):  
Danying Gao ◽  
Zhenqing Zhang ◽  
Yang Meng ◽  
Jiyu Tang ◽  
Lin Yang
Keyword(s):  
Blast Furnace ◽  
Mechanical Strength ◽  
Flue Gas ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
Flue Gas Desulfurization ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

This work aims to investigate the effect of additional flue gas desulfurization gypsum (FGDG) on the properties of calcium sulfoaluminate cement (CSAC) blended with ground granulated blast furnace slag (GGBFS). The hydration rate, setting time, mechanical strength, pore structure and hydration products of the CSAC-GGBFS mixture containing FGDG were investigated systematically. The results show that the addition of FGDG promotes the hydration of the CSAC-GGBFS mixture and improves its mechanical strength; however, the FGDG content should not exceed 6%.

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.

scholarly journals Control of the setting reaction and strength development of slag-blended volcanic ash-based phosphate geopolymer with the addition of boric acid

2021 ◽  
Author(s):  
Jean Noël Yankwa Djobo ◽  
Dietmar Stephan
Keyword(s):  
Blast Furnace ◽  
Boric Acid ◽  
Blast Furnace Slag ◽  
Volcanic Ash ◽  
Strength Development ◽  
Main Process ◽  
Reaction Products ◽  
Setting Times ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

AbstractThis work aimed to evaluate the role of the addition of blast furnace slag for the formation of reaction products and the strength development of volcanic ash-based phosphate geopolymer. Volcanic ash was replaced by 4 and 6 wt% of ground granulated blast furnace slag to accelerate the reaction kinetics. Then, the influence of boric acid for controlling the setting and kinetics reactions was also evaluated. The results demonstrated that the competition between the dissolution of boric acid and volcanic ash-slag particles is the main process controlling the setting and kinetics reaction. The addition of slag has significantly accelerated the initial and final setting times, whereas the addition of boric acid was beneficial for delaying the setting times. Consequently, it also enhanced the flowability of the paste. The compressive strength increased significantly with the addition of slag, and the optimum replaced rate was 4 wt% which resulted in 28 d strength of 27 MPa. Beyond that percentage, the strength was reduced because of the flash setting of the binder which does not allow a subsequent dissolution of the particles and their precipitation. The binders formed with the addition of slag and/or boric acid are beneficial for the improvement of the water stability of the volcanic ash-based phosphate geopolymer.

Evaluation of graded layer in ground granulated blast furnace slag based layered concrete

2021 ◽  
Vol 276 ◽  
pp. 122218
Author(s):  
Sangram K. Sahoo ◽  
Benu G. Mohapatra ◽  
Sanjaya K. Patro ◽  
Prasanna K. Acharya
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag
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