scholarly journals Fayalite Slag as Binder and Aggregate in Alkali-Activated Materials—Interfacial Transition Zone Study

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 1 ◽  
Author(s):  
Adediran ◽  
Yliniemi ◽  
Illikainen
Keyword(s):  
Transition Zone ◽  
Sodium Hydroxide Solution ◽  
Coal Fly Ash ◽  
Construction Materials ◽  
Fine Powder ◽  
Silicate Solution ◽  
Interfacial Transition Zone ◽  
Alkali Activation ◽  
Fayalite Slag ◽  
Alkali Activated

Alkali-activated materials (AAMs) are an environmentally friendly option for Portland cement mortars and concretes. Many industrial residues such as blast furnace slag and coal fly ash have been extensively studied and applied as AAM precursors but much less focus has been on the use of fayalite slags. Water-cooled fayalite slag comes in granular form, which is then milled into fine powder (d50 ~10 microns) prior to its alkali activation. In addition, the un-milled granular fayalite slag can be used as an aggregate to replace sand in mortar. The alkaline solution utilized for the study was a mix of 10 M sodium hydroxide solution and commercial potassium silicate solution. A liquid to solid ratio of 0.15 was held constant for all the mixes. The particle size distributions of the binder and the aggregates were optimized, and the microstructure and chemical composition of the interfacial transition zone (ITZ) was studied using scanning electron microscope coupled with energy dispersive X-ray spectroscopy. ITZ is a region that exists between the aggregate and the binder and this can influence the mechanical and transport properties of the construction materials. The results showed that the mechanical properties of mortar having fayalite slag as aggregate and binder was significantly higher than one with standard sand as aggregate. No distinct ITZ was found in the samples with fayalite slag as aggregate. The outer rim of the fayalite slag aggregate participated in the hardening reaction and this significantly contributed to the bonding and microstructural properties of the mortar samples. In contrast, an ITZ was observed in mortar samples with standard sand aggregates, which contributed to its lower strength.

Interfacial Transition Zone of Alkali-Activated Slag Concrete

2017 ◽  
Vol 114 (3) ◽  
Author(s):  
Tao Ji ◽  
Qiaoling Gao ◽  
Wenyuan Zheng ◽  
Xujian Lin ◽  
Hwai-Chung Wu
Keyword(s):  
Transition Zone ◽  
Interfacial Transition Zone ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

The Influence of Mechanical Activation of Fly Ash on the Toxic Metals Immobilization by Fly Ash-Based Geopolymers

2018 ◽  
Vol 761 ◽  
pp. 3-6 ◽  
Author(s):  
Violeta Nikolić ◽  
Miroslav Komljenović ◽  
Nataša Džunuzović ◽  
Tijana Ivanovic
Keyword(s):  
Fly Ash ◽  
Mechanical Activation ◽  
Toxic Metals ◽  
Structural Changes ◽  
Gas Adsorption ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Water Soluble ◽  
Alkali Activation ◽  
Alkali Activated

This paper investigates the influence of mechanical activation of fly ash on the toxic metals immobilization by fly ash-based geopolymers. Fly ash was firstly mechanically and then alkali-activated. Mechanical activation of fly ash was conducted in a planetary ball mill. Alkali activation of fly ash was carried out at room temperature by use of sodium silicate solution as an activator. Toxic metals (Pb and Cr) were added in the form of water soluble salts during the synthesis of geopolymers. The immobilization process was assessed via investigation of the mechanical and leaching properties of geopolymers. Structural changes of geopolymers during the toxic metals immobilization were assessed by means of gas adsorption and SEM analyses. Mechanical activation of fly ash led to a significant increase in geopolymer strength and to a reduced leaching of toxic metals from geopolymers.

scholarly journals Research on Eco-friendly Alkali Activated Concrete Incorporating Industrial Wastes

2019 ◽  
Vol 8 (9S2) ◽  
pp. 477-482
Keyword(s):  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Industrial Wastes ◽  
Liquid Sodium ◽  
Alkali Activation ◽  
Waste Glass Powder ◽  
Fine Aggregates ◽  
Alkaline Activator ◽  
Alkali Activated Concrete ◽  
Alkali Activated

In the present scenario, the production of green and sustainable concrete has become a must to substitute the ordinary Portland cement (OPC) concrete. It is an eminent fact that the manufacture of OPC requires burning of its raw materials which lead to a huge amount of carbon dioxide liberation; thus it requires a large amount of energy dissipation. The concrete produced using alkali activation has become renowned methods to replace the conventional OPC, which gives an answer to find a way to produce environmentally friendly concrete. In the current study, the alkaline activator used to activate the binder was sodium hydroxide solution dispersed in liquid sodium silicate. The utilization of industrial dissipate materials such as GGBS, fly ash, and waste glass powder was used as the binding ingredients, and stone crusher dust was used as fine aggregates. The experimental investigation showed that a quality concrete can be easily produced using alkali activation of industrial wastes satisfying its strength requirements. The statistical models developed shown that there is a significant relationship between various cube and cylinder strengths. Thus alkali-activated concrete(AAC) can effectively reduce the environmental hazards associated with OPC concrete, which also provides an effective way of utilizing major industrial byproducts

scholarly journals Radiological and physico-chemical characterization of red mud as an Al-containing precursor in inorganic binders for the building industry

2021 ◽  
Vol 36 (2) ◽  
pp. 182-191
Author(s):  
Ljiljana Kljajevic ◽  
Miljana Mirkovic ◽  
Sabina Dolenec ◽  
Katarina Ster ◽  
Mustafa Hadzalic ◽  
...  
Keyword(s):  
Construction Industry ◽  
Natural Radioactivity ◽  
Red Mud ◽  
Building Materials ◽  
Raw Materials ◽  
Construction Materials ◽  
Polymerization Process ◽  
Alkali Activation ◽  
Silica Alumina ◽  
Alkali Activated

The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milici, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials.

scholarly journals Low-Carbon Concrete Based on Binary Biomass Ash–Silica Fume Binder to Produce Eco-Friendly Paving Blocks

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1534 ◽  
Author(s):  
André Henrique Campos Teixeira ◽  
Paulo Roberto Ribeiro Soares Junior ◽  
Thiago Henrique Silva ◽  
Richard Rodrigues Barreto ◽  
Augusto Cesar da Silva Bezerra
Keyword(s):  
Organic Matter ◽  
Portland Cement ◽  
Silica Fume ◽  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Alkali Activation ◽  
Low Carbon ◽  
Biomass Ash ◽  
Microstructural Investigation ◽  
Alkali Activated

The civil construction industry consumes huge amounts of raw materials and energy, especially infrastructure. Thus, the use of eco-friendly materials is indispensable to promote sustainable development. In this context, the present work investigated low-carbon concrete to produce eco-friendly paving blocks. The binder was defined according to two approaches. In the first, a binary binder developed with eucalyptus biomass ash (EBA) and silica fume (SF) was used, in total replacement for Portland cement. In the second, the mixture of residues was used as a precursor in alkali-activation reactions, forming alkali-activated binder. The experimental approach was carried out using five different mixtures, obtained by varying the amount of water or sodium hydroxide solution. The characterization of this new material was carried out using compressive strength, expandability, water absorption, deep abrasion, microstructural investigation, and organic matter degradation potential. The results showed that the EBA-SF system has a performance compatible with Portland cement when used as an alternative binder, in addition to functioning as a precursor to alkali-activated concrete. The blocks produced degraded organic matter, and this degradation is more intense with the incidence of UV. In this way, the EBA-SF binder can be successfully used for the manufacture of ecological paving blocks with low carbon emissions.

Perlite Concrete Based on Alkali Activated Cements

2014 ◽  
Vol 897 ◽  
pp. 280-283
Author(s):  
Vít Petranek ◽  
Pavel Krivenko ◽  
Оleg Petropavlovsky ◽  
Sergii Guzii
Keyword(s):  
Transition Zone ◽  
Heat Insulation ◽  
Interfacial Transition Zone ◽  
Cement Stone ◽  
High Durability ◽  
Alkali Activated

The use of the alkali activated cements for the manufacture of perlite concrete pressed and vibro-pressed products for heat insulation intended for various purposes was studied. The interfacial transition zone perlite grain cement stone was examined in order to reveal features of its formation. These features allow to create a dense and strong shell/caging around the perlite grain which helps to avoid its corrosion and produce perlite concretes with high durability.

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