scholarly journals Effects of concrete quality and natural Johannesburg environment on concrete carbonation rate

2018 ◽  
Vol 199 ◽  
pp. 02008
Author(s):  
Jacob Olumuyiwa Ikotun
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Combined Effects ◽  
Concrete Carbonation ◽  
Granulated Blast Furnace Slag ◽  
Concrete Quality ◽  
Binder Type ◽  
Furnace Slag

This study presents the results of a project undertaken to study the combined effects of concrete quality (binder type, w/b, and duration of initial moist curing) and natural Johannesburg environment on carbonation rate of concretes containing 100% PC, 35% fly ash (FA), 50% ground granulated blast-furnace slag (BS), 10% silica fume (SF) and (30% BS + 10% SF). The results show that apart from the SF blended concretes, the carbonation rate of the SCM blended concretes are higher than the PC concretes. Reducing the w/b and increasing the duration of initial moist curing reduced the carbonation rate in the concretes. The indoor exposed concretes have the highest carbonation rates and reducing the w/b ratio is more efficient and sustainable in lowering the carbonation rate rather than extending the duration of the initial moist curing.

Influence of Mineral Admixtures on the Carbonation Resistance and Chloride Permeability of Steam-Cured HPC

2011 ◽  
Vol 477 ◽  
pp. 366-374
Author(s):  
Jian Hua Wu ◽  
Yun Lan Liu
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Chloride Permeability ◽  
Concrete Carbonation ◽  
Granulated Blast Furnace Slag ◽  
Carbonation Resistance ◽  
Furnace Slag

This paper studies the influence of different mineral admixtures（fly ash and ground granulated blast furnace slag）on the carbonation resistance and chloride permeability of steam-cured HPC. The test results show that under the condition of steam-cured and standard-cured, incorporating 20-30% of the ground granulated blast furnace slag or 15-20% of fly ash decreased the alkalinity and the carbonation resistance of the concrete; with the increase of the proportion of the mineral admixture in concrete, carbonation resistance of HPC was decreased; incorporating 20-30% of the ground granulated blast furnace slag or 15-20% of fly ash improved the chloride permeability of steam-cured concrete, and the influence of ground granulated blast furnace slag is better than that of the fly ash.

scholarly journals A Taguchi Approach for Optimizing Design Mixture of Geopolymer Concrete Incorporating Fly Ash, Ground Granulated Blast Furnace Slag and Silica Fume

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1279
Author(s):  
Sundaravadivelu Karthik ◽  
Kaliyaperumal Saravana Raja Mohan
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Taguchi Approach ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

In recent decades, geopolymer concrete (GPC) has been extensively researched as a potential substitute sustainable building material that may reduce CO2 emissions due to its utilization of industrial by-products. Fly ash (FA) and ground-granulated blast-furnace slag (GGBFS) are preferred geopolymer raw materials due to their obtainability and high alumina and silica concentrations. GGBFS-FA based GPC offers a clean and sustainable development technology alternative. In this study, the Taguchi method was used to optimize the mixed proportions of geopolymer concrete to achieve desired strength criteria. Four factors and four levels were considered: binder content, including four combinations of FA and GGFBS dosage, dosage of superplasticizer (0.5, 1.0, 1.5 and 2%), Na2SiO3/NaOH ratio (1.5, 2.0, 2.5 and 3), and molarity (6, 8, 10 and 12). Using these ingredients and factors, the effect of compressive strength was examined. The Taguchi approach using an L16 orthogonal array was employed to find the optimum condition of every factor while limiting the number of experiments. The findings indicated that the optimum synthesis conditions for maximum compressive strength obtained from the binder comprised 45% of FA, 45% of GGBFS and 10% of silica fume, 1.5% dosage of superplasticizer, Na2SiO3/NaOH ratio = 1.5, and 12 molar contents.

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.

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.

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