Durability of Alkali-Activated Fly Ash/Slag Concrete

2017 ◽  
Vol 904 ◽  
pp. 157-161 ◽  
Author(s):  
Mao Chieh Chi ◽  
Hsian Chen ◽  
Tsai Lung Weng ◽  
Ran Huang ◽  
Yih Chang Wang
Keyword(s):  
Fly Ash ◽  
Total Charge ◽  
Test Results ◽  
Mass Ratio ◽  
Modulus Ratio ◽  
Granulated Blast Furnace Slag ◽  
Alkali Activated Binders ◽  
Furnace Slag ◽  
Alkali Activated ◽  
Better Than

This study investigated the durability of alkali-activated binders based on blends of fly ash (FA) and ground granulated blast furnace slag (GGBFS). Five fly ash-to-slag ratios of 100/0, 75/25, 50/50, 25/75, and 0/100 by mass were selected to produce alkali-activated fly ash/slag (AAFS) concrete. Sodium oxide (Na2O) concentrations of 6% and 8% of binder weight and activator modulus ratios (mass ratio of SiO2 to Na2O) of 0.8, 1.0, and 1.23 were used as alkaline activators. Test results show that the total charge passed of AAFS concrete is between 2500 and 4000 coulombs, higher than the comparable OPC concrete. However, AAFS concrete exposed to sulfate attack performed better than OPC concrete. Based on the results, 100% slag-based AAFS concrete with Na2O concentration of 8% and activator modulus ratio of 1.23 has the superior performances.

scholarly journals Optimizing Precursors and Reagents for the Development of Alkali-Activated Binders in Ambient Curing Conditions

2021 ◽  
Vol 5 (2) ◽  
pp. 59
Author(s):  
Dhruv Sood ◽  
Khandaker M. Anwar Hossain
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Curing Conditions ◽  
Granulated Blast Furnace Slag ◽  
Hardened State ◽  
Alkali Activated Binders ◽  
Furnace Slag ◽  
Alkali Activated ◽  
Ambient Curing

Alkali-activated binders (AABs) are developed through the activation of aluminosilicate-rich materials using alkaline reagents. The characteristics of AABs developed using a novel dry-mixing technique incorporating powder-based reagents/activators are extensively explored. A total of forty-four binder mixes are assessed in terms of their fresh and hardened state properties. The influence of mono/binary/ternary combinations of supplementary cementitious materials (SCMs)/precursors and different types/combinations/dosages of powder-based reagents on the strength and workability properties of different binder mixes are assessed to determine the optimum composition of precursors and the reagents. The binary (55% fly ash class C and 45% ground granulated blast furnace slag) and ternary (25% fly ash class C, 35% fly ash class F and 40% ground granulated blast furnace slag) binders with reagent-2 (calcium hydroxide and sodium sulfate = 2.5:1) exhibited desired workability and 28-day compressive strengths of 56 and 52 MPa, respectively. Microstructural analyses (in terms of SEM/EDS and XRD) revealed the formation of additional calcium aluminosilicate hydrate with sodium or mixed Ca/Na compounds in binary and ternary binders incorporating reagent-2, resulting in higher compressive strength. This research confirms the potential of producing powder-based cement-free green AABs incorporating binary/ternary combinations of SCMs having the desired fresh and hardened state properties under ambient curing conditions.

scholarly journals Effects of Composition Type and Activator on Fly Ash-Based Alkali Activated Materials

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 63
Author(s):  
Chan-Yi Lin ◽  
Tai-An Chen
Keyword(s):  
Fly Ash ◽  
Sodium Hydroxide ◽  
Blast Furnace Slag ◽  
Raw Material ◽  
Granulated Blast Furnace Slag ◽  
Different Types ◽  
Short And Long Term ◽  
Furnace Slag ◽  
Alkali Activated

The compressive strengths of fly ash-based alkali-activated materials (AAM), produced using various activators of only sodium hydroxide, were measured. Fly ash-based AAM specimens, produced by mixing different kinds of fly ash and ground granulated blast-furnace slag (GGBFs) with an activator containing only sodium hydroxide, were cured at ambient temperature, and then placed in air for different numbers of days. The short- and long-term compressive strengths and shrinkage of fly ash-based AAM were measured and compared to one another. The effects of type of fly ash, alkali-equivalent content, GGBFs replace percentage, and ages on the compressive strengths and shrinkage of fly ash-based AAM were investigated. Even when different fly ash was used as the raw material for AAM, a similar compressive strength can be achieved by alkali-equivalent content, GGBFs replaces percentage. However, the performance of shrinkage due to different types of fly ash differed significantly.

Effect of the Combined Using of Fly Ash and Granulated Blast Furnace Slag on Properties of Cementless Alkali-Activated Mortar

2011 ◽  
Vol 287-290 ◽  
pp. 916-921
Author(s):  
Kyung Taek Koh ◽  
Gum Sung Ryu ◽  
Si Hwan Kim ◽  
Jang Hwa Lee
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Curing Temperature ◽  
Mixture Ratio ◽  
Granulated Blast Furnace Slag ◽  
Alkaline Activator ◽  
Furnace Slag ◽  
Alkali Activated

This paper examines the effects of the mixture ratio of fly ash/slag, the type of alkaline activators and curing conditions on the workability, compressive strength and microstructure of cementless alkali-activated mortar. The investigation showed that the mixture ratio of fly ash/slag and the type of alkaline activator have significant influence on the workability and strength, whereas the curing temperature has relatively poor effect. An alkali-activated mortar using a binder composed of 50% of fly ash and 50% of granulated blast furnace slag and alkaline activator made of 9M NaOH and sodium silicate in proportion of 1:1 is seen to be able to develop a compressive strength of 65 MPa at age of 28 days even when cured at ambient temperature of 20°C.

MECHANICAL PROPERTIES OF SELF-COMPACTING GEOPOLYMER CONCRETE CONTAINING SPENT GARNET AS REPLACEMENT FOR FINE AGGREGATE

2017 ◽  
Vol 79 (3) ◽  
Author(s):  
Habeeb Lateef Muttashar ◽  
Mohd Warid Hussin ◽  
Mohd Azreen Mohd Ariffin ◽  
Jahangir Mirza ◽  
Nor Hasanah ◽  
...  
Keyword(s):  
Environmental Problems ◽  
Fine Aggregate ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Mass Ratio ◽  
River Sand ◽  
Conventional Concrete ◽  
Granulated Blast Furnace Slag ◽  
Concrete Mixtures ◽  
Furnace Slag

Millions of tons of spent garnet, a by-product of surface treatment operations, are disposed of in landfills, oceans, rivers, and quarries, among others every year, thus it causes environmental problems. The main objective of this study is to evaluate spent garnet as a sand replacement in concrete prepared with ground granulated blast furnace slag (GGBS)-based self-compacting geopolymer concrete (SCGC). Concrete mixtures containing 0%, 25%, 50%, 75% and 100% spent garnet as a replacement for river sand were prepared with a constant Liquid/Binder (L/B) mass ratio equal to 0.4. Compressive, flexural and splitting tensile strengths as well as workability tests (slump, L-box, U-box and T50) were conducted on concrete containing spent garnet. As per specification and guidelines for self-compacting concrete (EFNARC) standard, the test results showed that the concrete’s workability increased with the increase of spent garnet, while all the other strength values were consistently lower than conventional concrete (SCGC) at all stages of replacement. The results recommended that spent garnet should be used in concrete as a sand replacement up to 25% to reduce environmental problems, costs and the depletion of natural resources.

scholarly journals Kajian Kuat Mekanis Alkali-Activated Mortar (AAM)

Kilat ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 101-107
Author(s):  
Muhammad Sofyan
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Bottom Ash ◽  
Palm Oil Fuel Ash ◽  
Granulated Blast Furnace Slag ◽  
Fuel Ash ◽  
Oil Fuel ◽  
Furnace Slag ◽  
Alkali Activated

Mortar salah satu material yang memiliki manfaat yang beraneka ragam dalam konstruksi bangunan.  Sejauh ini, mortar konvensional digunakan sebagai bahan plester atau coating pada bangunan. Bahan pengikat utama mortar pada dasarnya masih mengandalkan semen. Pemanfaatan Batu bara pada pembangkit listrik tenaga uap masih menjadi salah satu arus utama sebagai pendukung kebutuhan energi listrik. Penumpukan hasil sisa pembakaran batu bara seperti fly ash dan bottom ash berpotensi mengganggu stabilitas Ekosistem lingkungan. Alkali-Activated mortar dengan mengandalkan larutan alkali activator yang direaksikan dengan material pozzolanic seperti fly ash, Ground Granulated Blast Furnace Slag (GGBFS), Palm Oil Fuel Ash (POFA)ldan lain-lain dapat menjadi salah satu solusi dalam mengurangi limbah fly-ash yang menumpuk. Dalam beberapa riset riset terdahulu idealnya kontrol mutu dari Alkali Activated mortar dapat ditinjiau pada kekuatan mekanisnya seperti kuat tekan dan lentur Dalam artikel ini akan ditinjau bagaimana kekuatan mekanis pada beberapa jenis Alkali-Activated Mortar. Dari studi-studi yang akan dibahas tersebut akan ditarik sebuah kesimpulan berdasarkan data-data pengujian mekanis yan pada akhirnya dapat memberi rekomendasi tentang bagaimana performa mekanis pada Alkali-Activated mortar.

Sign in / Sign up

Export Citation Format

Share Document