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 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 Bio-based construction materials for a sustainable future

2019 ◽  
Author(s):  
Rijk Block ◽  
Barbara Kuit ◽  
Torsten Schröder ◽  
Patrick Teuffel
Keyword(s):  
Construction Industry ◽  
Structural Engineering ◽  
Building Materials ◽  
Raw Materials ◽  
Construction Materials ◽  
Flax Fibres ◽  
The Past ◽  
Natural Building ◽  
Paris Climate Agreement ◽  
Primary Materials

<p>The structural engineering community has a strong responsibility to contribute to a more efficient use of natural resources. Nowadays the construction industry is by far the most resource intense industry sector, approximately 40-50% of all primary raw materials are used, which raises the question about the architects and engineer’s accountability. In this context and as a result of the Paris Climate agreement the Dutch government defined the program “Nederland Circulair in 2050”, which states the ambition to use 50% less primary materials in 2030 and to have a full circular economy in 2050.</p><p>One possible approach to achieve these ambitious goals is the application of renewable, bio-based materials in the built environment and to replace traditional, typically cement-based, materials. Already in the past natural building materials, such as timber and bamboo have been used widely, but in recent years new materials came up and provide new opportunities to be used in the construction industry. The authors explored various alternatives, such as hemp and flax fibres, mycelium and lignin-based fibres for composite materials, which will be described with various experimental and realised case studies.</p>

scholarly journals Case Study: LCA Methodology Applied to Materials Management in a Brazilian Residential Construction Site

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
João de Lassio ◽  
Josué França ◽  
Kárida Espirito Santo ◽  
Assed Haddad
Keyword(s):  
Life Cycle ◽  
Construction Industry ◽  
Environmental Impacts ◽  
Building Materials ◽  
Raw Materials ◽  
Construction Materials ◽  
Ceramic Materials ◽  
Environmental Indicators ◽  
Life Cycle Thinking ◽  
Lca Methodology

The construction industry is increasingly concerned with improving the social, economic, and environmental indicators of sustainability. More than ever, the growing demand for construction materials reflects increased consumption of raw materials and energy, particularly during the phases of extraction, processing, and transportation of materials. This work aims to help decision-makers and to promote life cycle thinking in the construction industry. For this purpose, the life cycle assessment (LCA) methodology was chosen to analyze the environmental impacts of building materials used in the construction of a residence project in São Gonçalo, Rio de Janeiro, Brazil. The LCA methodology, based on ISO 14040 and ISO 14044 guidelines, is applied with available databases and the SimaPro program. As a result, this work shows that there is a substantial waste of nonrenewable energy, increasing global warming and harm to human health in this type of construction. This study also points out that, for this type of Brazilian construction, ceramic materials account for a high percentage of the mass of a total building and are thus responsible for the majority of environmental impacts.

scholarly journals Iron and Aluminium Production Wastes as Exclusive Components of Alkali Activated Binders—Towards a Sustainable Alternative

2021 ◽  
Vol 13 (17) ◽  
pp. 9938
Author(s):  
Nuno Cristelo ◽  
Fernando Castro ◽  
Tiago Miranda ◽  
Zahra Abdollahnejad ◽  
Ana Fernández-Jiménez
Keyword(s):  
Co2 Emissions ◽  
Building Materials ◽  
Negative Impact ◽  
Raw Materials ◽  
Construction Materials ◽  
Heat Of Hydration ◽  
Sustainable Construction ◽  
Alkaline Solutions ◽  
By Products ◽  
Alkali Activated

The sustainability of resources is becoming a worldwide concern, including construction and building materials, especially with the alarming increase rate in global population. Alternative solutions to ordinary Portland cement (OPC) as a concrete binder are being studied, namely the so-called alkali-activated cements (AAC). These are less harmful to the environment, as lower CO2 emissions are associated with their fabrication, and their mechanical properties can be similar to those of the OPC. The aim of developing alkali-activated materials (AAM) is the maximization of the incorporated recycled materials, which minimises the CO2 emissions and cost, while also achieving acceptable properties for construction applications. Therefore, various efforts are being made to produce sustainable construction materials based on different sources and raw materials. Recently, significant attention has been raised from the by-products of the steelmaking industry, mostly due to their widespread availability. In this paper, ladle slag (LS) resulting from steelmaking operations was studied as the main precursor to produce AAC, combined with phosphating bath sludge—or phosphate sludge (PS)—and aluminium anodising sludge (AS), two by-products of the surface treatment of metals, in replacement rates of 10 and 20 wt.%. The precursors were activated by two different alkaline solutions: a combination of commercial sodium hydroxide and sodium silicate (COM), and a disposed solution from the cleaning of aluminium extrusion steel dies (CLE). This study assesses the influence of these by-products from the steelmaking industry (PS, AS and CLE) on the performance of the alkali-activated LS, and specifically on its fresh and hardened state properties, including rheology, heat of hydration, compressive strength and microstructure and mineralogy (X-ray diffraction, scanning electron microscopy coupled with energy dispersive spectroscopy and Fourier transform infra-red. The results showed that the CLE had no negative impact on the strength of the AAM incorporating PS or/and AS, while increasing the strength of the LS alone by 2×. Additionally, regardless of the precursor combination, the use of a commercial activator (COM) led to more fluid pastes, compared with the CLE.

scholarly journals Physicochemical, mineralogical and radiological properties of red mud samples as secondary raw materials

2017 ◽  
Vol 32 (3) ◽  
pp. 261-266 ◽  
Author(s):  
Snezana Nenadovic ◽  
Gabor Mucsi ◽  
Ljiljana Kljajevic ◽  
Miljana Mirkovic ◽  
Milos Nenadovic ◽  
...  
Keyword(s):  
Red Mud ◽  
Building Materials ◽  
Raw Materials ◽  
Preliminary Investigation ◽  
Construction Materials ◽  
Hazard Index ◽  
Raw Material ◽  
Radiation Hazard ◽  
Absorbed Dose Rate ◽  
Radium Equivalent Activity

The main goal of the presented research was the preliminary investigation of possibility of red mud - Hungarian dump sites Almasfuzito (sample A) and Ajka (sample B) - application as a pigment or as a raw material for use in the construction materials industry. Also, the aim of this work was the characterization of red mud as industrial waste generated by the Bayer process in the aluminum industry - which may cause environmental problems if appropriate treatment is not carried out. The main mineral phases of both red mud are hematite (Fe2O3), calcite (CaCO3), gibbsite (Al(OH)3) and they consists of particles of median particle size 2.1 mm (sample A) and 2.5 mm (sample B) and have a characteristic red color, which was the reason for its testing for use in the industry of building materials as a pigment for standard concrete mixtures. The radionuclides content in the samples was determined by gamma spectrometry, and the radiological hazards originating from 238U, 232Th, 40K in the samples, were assessed through the radium equivalent activity, and the external radiation hazard index. The absorbed dose rate and the annual effective dose were calculated in accordance with the UNSCEAR 2010 report and the results are presented in this paper.

Fundamentals of Geopolymers and Related Alkali Activated Materials

2014 ◽  
Vol 803 ◽  
pp. 144-147 ◽  
Author(s):  
J. Temuujin ◽  
A. Minjigmaa ◽  
U. Bayarzul ◽  
Ts. Zolzaya ◽  
B. Davaabal ◽  
...  
Keyword(s):  
Fly Ash ◽  
Building Materials ◽  
Raw Materials ◽  
Construction Materials ◽  
Materials Chemistry ◽  
Low Carbon ◽  
Pond Ash ◽  
Sustainable Usage ◽  
By Products ◽  
Alkali Activated

With the increasing rate of depletion of natural raw materials for production of building materials, their sustainable usage is clearly an important topic for consideration. For instance, 1 tonne ordinary Portland cement (OPC) requires 1.7 tonnes of raw materials, 1.0 tonne of coal and 100 kWh of electricity. One tonne of cement emits 0.8 - 1 tonne of CO2 into atmosphere globally contributing ~5% of total manmade carbon dioxide. Therefore, the development of new, sustainable, low carbon footprint construction materials is an important task for materials scientists and civil engineers. One type of binder that is attracting particular attention around the world is alkali-aluminosilicate chemistry based material the so-called geopolymers. In this presentation we will discuss the fundamentals of geopolymer chemistry and the similarities to and differences from conventional alkali activated materials chemistry. Particular attention will be given to our latest results on the preparation of geopolymer type paste and concrete from fly ash. Mechanical activation of fly ash caused a decrease in porosity with a partial amorphisation of the crystalline constituents. Geopolymer type paste prepared from 30 minute milled Darkhan pond ash showed increase in 7 day compressive strengths by 7 times reaching of 15.4 (4.6) MPa. Keywords: Geopolymer binder, alkali-activated materials, coal combustion by products

scholarly journals An Alternative to Clay in Building Materials: Red Mud Sintering Using Fly Ash via Taguchi’s Methodology

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Suchita Rai ◽  
Dilip H. Lataye ◽  
M. J. Chaddha ◽  
R. S. Mishra ◽  
P. Mahendiran ◽  
...  
Keyword(s):  
Fly Ash ◽  
Construction Industry ◽  
Red Mud ◽  
Morphological Analysis ◽  
Building Materials ◽  
Sintering Temperature ◽  
Bauxite Residue ◽  
Significant Parameter ◽  
Alkaline Waste ◽  
Free Caustic Soda

“Red mud” or “bauxite residue” is a highly alkaline waste generated from alumina refinery with a pH of 10.5–12.5 which poses serious environmental problems. Neutralization or its treatment by sintering in presence of additives is one of the methods for overcoming the caustic problem as it fixes nearly all the leachable free caustic soda present in red mud. In the present study, feasibility of reducing the alkaline nature of red mud by sintering using fly ash as an additive via Taguchi methodology and its use for brick production, as an alternative to clay, is investigated. The analysis of variance (ANOVA) shows that sintering temperature is the most significant parameter in the process. A pH of 8.9 was obtained at 25–50% of red mud and 50–75% fly ash with water and temperature of . Alternatively 50% of red mud can be mixed with 50% of fly ash with water at temperature of to get a pH of about 8.4. The mechanism of this process has been explained with also emphasis on chemical, mineralogical, and morphological analysis of the sintered red mud. The results would be extremely useful in utilization of red mud in building and construction industry.

Alternative Concrete – Geopolymer Concrete

2021 ◽  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Industry ◽  
Building Material ◽  
Construction Materials ◽  
Raw Material ◽  
Geopolymer Concrete ◽  
Sustainable Solutions ◽  
New Construction ◽  
Alkali Activated

Concrete is the most versatile, durable and reliable material and is the most used building material. It requires large amounts of Portland cement which has environmental problems associated with its production. Hence, an alternative concrete – geopolymer concrete is needed. The general aim of this book is to make significant contributions in understanding and deciphering the mechanisms of the realization of the alkali-activated fly ash-based geopolymer concrete and, at the same time, to present the main characteristics of the materials, components, as well as the influence that they have on the performance of the mechanical properties of the concrete. The book deals with in-depth research of the potential recovery of fly ash and using it as a raw material for the development of new construction materials, offering sustainable solutions to the construction industry.

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.

scholarly journals Mechanical Properties of Alkali Activated Material Based on Red Clay and Silica Gel Precursor

2021 ◽  
Vol 25 (1) ◽  
pp. 931-943
Author(s):  
Girts Bumanis ◽  
Danute Vaiciukyniene
Keyword(s):  
Silica Gel ◽  
Raw Materials ◽  
Raw Material ◽  
Alkali Activation ◽  
Production Plant ◽  
X Ray Diffraction ◽  
Red Clay ◽  
Significant Strength ◽  
Naoh Solution ◽  
Alkali Activated

Abstract The search for alternative alumosilicates source for production of alkali activated materials (AAM) is intensively researched. Wide spread of natural materials such as clays and waste materials are one of potential alternatives. In this research AAM was made from local waste brick made of red clay and calcined low-carbonate illite clay precursor and its properties evaluated. Waste silica gel containing amorphous silica from fertilizer production plant was proposed as additional raw material. 6 M and 7 M NaOH alkali activation solutions were used to obtain AAM. Raw materials were characterized by X-ray diffraction, laser particle size analyser, DTA/TG. Raw illite clay was calcined at a temperature of 700 to 800 °C. Waste brick was ground similar as raw clay and powder was obtained. Replacement of red clay with silica gel from 2–50 wt.% in mixture composition was evaluated. Results indicate that the most effective activator was 6 M NaOH solution and AAM with strength up to 13 MPa was obtained. Ground brick had the highest strength results and compressive strength of AAM reached 25 MPa. Silica gel in small quantities had little effect of AAM strength while significant strength reduction was observed with the increase silica gel content. The efflorescence was observed for samples with silica gel.

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