scholarly journals Parametric Studies Regarding the Development of Alkali-Activated Fly Ash-Based Geopolymer Concrete Using Romanian Local Raw Materials

Proceedings ◽  
2020 ◽  
Vol 63 (1) ◽  
pp. 11
Author(s):  
Adrian-Victor Lăzărescu ◽  
Henriette Szilagyi ◽  
Cornelia Baeră ◽  
Andreea Hegyi
Keyword(s):  
Fly Ash ◽  
Building Materials ◽  
Negative Impact ◽  
Raw Materials ◽  
Geopolymer Concrete ◽  
Human Needs ◽  
Alternative Material ◽  
Parametric Studies ◽  
And Performance ◽  
Alkali Activated

Current research and development policies in the field of building materials, in the context of sustainable development, have the main objectives of increasing the safety and performance of the built environment at the same time as reducing pollution and its negative impact. Today, the idea that the sustainable city of the future should meet human needs and maintain a higher quality of life is worldwide unanimously accepted. The aim of this paper is to present results regarding the production of alkali-activated fly ash-based geopolymer concrete, a new, alternative material, produced using local available raw materials from Romania.

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.

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

Leaching Behavior and Immobilization of Heavy Metals in Geopolymer Synthesized from Red Mud and Fly Ash

2018 ◽  
Vol 777 ◽  
pp. 518-522 ◽  
Author(s):  
Hoc Thang Nguyen ◽  
Thu Ha Bui ◽  
Vo Thi Ha Quyen Pham ◽  
Minch Quang Do ◽  
Minh Duc Hoang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Red Mud ◽  
Industrial Waste ◽  
Power Plants ◽  
Building Materials ◽  
Negative Impact ◽  
Raw Materials ◽  
Thermal Power ◽  
Aluminum Production

Fly ash is an industrial waste from coal-fired thermal power plants whereas red mud is an industrial waste generated during aluminum production from bauxite. If both fly ash and red mud are not properly managed, they could cause negative impact on the environment. This study utilized red mud and fly ash in combination with sodium silicate solution to produce a geopolymer-based material which can be used as building materials. This study focussed on the leachability of heavy metals in the raw materials and the geopolymer as this would be significant in assessing the environmental impact of the product. Leachability of heavy metals such as Cu, Zn, Cd, Pb, Fe, and Cr was evaluated based on European standard (EN 124572 – 2, EU CEN TC292/ CEN TC 308) with pH values at 7. The results showed that raw materials (red mud and fly ash) have higher leachability than geopolymer specimens. And the values of leaching tests for heavy metals in the geopolymer - based materials belonged to limits of EULFD and USEPA.

scholarly journals Mix Design and Mechanical Properties of Fly Ash and GGBFS-Synthesized Alkali-Activated Concrete (AAC)

2019 ◽  
Vol 4 (2) ◽  
pp. 20 ◽  
Author(s):  
Ramamohana Reddy Bellum ◽  
Ruben Nerella ◽  
Sri Rama Chand Madduru ◽  
Chandra Sekhar Reddy Indukuri
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Raw Materials ◽  
Construction Materials ◽  
Xrd Analysis ◽  
Mix Design ◽  
Geopolymer Concrete ◽  
Curing Conditions ◽  
Factors Affecting ◽  
Alkali Activated

Cement is one of the construction materials widely used around the world in order to develop infrastructure and it is also one of the factors affecting economies. The production of cement consumes a lot of raw materials like limestone, which releases CO2 into the atmosphere and thus leads to global warming. Many investigations are underway in this area, essentially focusing on the eco-accommodating environment. In the research, an alternative material to cement binder is geopolymer binder, with the same efficiency. This paper presents scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis of factory byproducts (i.e., fly ash and ground granulated blast furnace slag (GGBFS)). The mix design process for the manufacture of alkali-activated geopolymer binders synthesized by fly ash and GGBFS is presented. The mechanical properties (compression, split tensile and flexural strength, bond strength) of geopolymer concrete at different mix proportions and at dissimilar curing conditions were also investigated. Geopolymer concrete synthesized with 30% fly ash and 70% GGBFS has better properties at 14 M of NaOH and cured in an oven for 24 h at 70 °C.

scholarly journals The Influence of Cement Substitution by Biomass Fly Ash on the Polymer–Cement Composites Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3079
Author(s):  
Beata Jaworska ◽  
Dominika Stańczak ◽  
Joanna Tarańska ◽  
Jerzy Jaworski
Keyword(s):  
Fly Ash ◽  
Building Materials ◽  
Raw Materials ◽  
Combustion Process ◽  
Biomass Combustion ◽  
Cement Composites ◽  
Cement Mortars ◽  
Mineral Additive ◽  
Biomass Fly Ash

The generation of energy for the needs of the population is currently a problem. In consideration of that, the biomass combustion process has started to be implemented as a new source of energy. The dynamic increase in the use of biomass for energy generation also resulted in the formation of waste in the form of fly ash. This paper presents an efficient way to manage this troublesome material in the polymer–cement composites (PCC), which have investigated to a lesser extent. The research outlined in this article consists of the characterization of biomass fly ash (BFA) as well as PCC containing this waste. The characteristics of PCC with BFA after 3, 7, 14, and 28 days of curing were analyzed. Our main findings are that biomass fly ash is suitable as a mineral additive in polymer–cement composites. The most interesting result is that the addition of biomass fly ash did not affect the rheological properties of the polymer–cement mortars, but it especially influenced its compressive strength. Most importantly, our findings can help prevent this byproduct from being placed in landfills, prevent the mining of new raw materials, and promote the manufacture of durable building materials.

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.

Study on Wheat Straw Reinforced FGD Gypsum-Fly Ash Block

2012 ◽  
Vol 549 ◽  
pp. 737-740
Author(s):  
Jiang Zhu ◽  
Guo Zhong Li
Keyword(s):  
Material Processing ◽  
Fly Ash ◽  
Wheat Straw ◽  
Raw Materials ◽  
Processing Technology ◽  
Fgd Gypsum ◽  
Material Processing Technology ◽  
And Performance

FGD gypsum, fly ash and wheat straw are taken as main raw materials; waterproof agent, water reducer, activator and composite retarder are chosen as admixtures, and wheat straw reinforced desulfurization gypsum block is produced through reasonable processing technology. Block ratios of material, processing technology and performance are analyzed.

scholarly journals Use of Plastic Aggregates in Concrete

2019 ◽  
Vol 9 (1) ◽  
pp. 4406-4412
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Fly Ash ◽  
Construction Industry ◽  
Negative Impact ◽  
Raw Materials ◽  
Waste Products ◽  
Waste Plastic ◽  
Coarse Aggregates ◽  
Materials Used

There is no doubt concrete is most useful thing in construction industry but it has a negative impact also, just like a coin has two faces. Raw materials used in manufacturing of concrete affects the environment in one or the another negative way. Like manufacturing of cement produce carbon dioxide whereas the production of aggregates adds dust to the environment. Production of coarse aggregates also impact the geology of the area from they were extracted. A step taken in this direction is the use of waste products along with or in replacement of cement. Many of these materials are already in use, like silica fume, fly ash etc. In this study, plastic coarse aggregates were used in place of natural coarse aggregates. Plastic aggregates were produced by little processing of waste plastic. Plastic is the biggest threat to the environment, and it is affecting the environment rapidly. Some recent studies show that it can be used construction industry due to some of its properties like inert behavior, resistance to degradation etc. Also use of waste plastic can help in reducing plastic waste Various experiments were performed to test the mechanical properties of the concrete with plastic coarse aggregates. Concrete was prepared using plastic coarse aggregates in varying proportions of 0, 2.5, 5, 7.5 and 10%

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