Influence of Different Mineral Precursors on the Properties of Fly Ash Based Alkali-Activated Mortars

2018 ◽  
Vol 761 ◽  
pp. 73-78 ◽  
Author(s):  
Matej Špak ◽  
Pavel Raschman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Chemical Composition ◽  
Coal Combustion ◽  
Pure Aluminum ◽  
Partial Replacement ◽  
Black Coal ◽  
Fly Ashes ◽  
Final Composition ◽  
Alkali Activated

Alkali-activated materials based on fly ash are widely developed and also produced on the present. Some of fly ashes are not suitable for production of alkali-activated materials because of their inconvenient chemical composition. Alumina-silicates are the most important components that are needed to accomplish the successful reaction. The proper content of amorphous phase of alumina-silicates and its proportion as well should be provided for the final composition of alkali-activated materials. The influence of pure aluminum oxide powder as well as raw milled natural perlite on mechanical properties and durability of alkali-activated mortars was investigated. These minerals were used as partial replacement of fly ash coming from black coal combustion. In addition, the mortars were prepared by using different alkali activators.

Mechanical Properties of Mortars Prepared by Alkali Activated Fly Ash Coming from Different Production Batches

2015 ◽  
Vol 244 ◽  
pp. 140-145 ◽  
Author(s):  
Matej Špak ◽  
Pavel Raschman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Materials ◽  
Chemical Properties ◽  
Raw Material ◽  
Fly Ashes ◽  
Coal Burning ◽  
Alkali Solutions ◽  
One Year ◽  
Alkali Activated

Fly ash is a well utilizable secondary raw material for the production of alkali activated construction materials. It is a significant alumina-silicates source suitable for the chemical reaction resulting in hardened composites. Physical and chemical properties of fly ashes as a co-product of coal burning mainly depend on characteristics of coal, burning temperature and combustion conditions. High variability of the properties of fly ash causes an uncertainty in the properties of alkali activated mortars. Time behaviour of the composition of the fly ash produced in a heating plant located in Košice, Slovakia as well as leaching behaviour of both alumina and silica from particular batches during one-year period was documented. Leaching tests were carried out using the distilled water and alkali solutions with three different concentrations. Both compressive and tensile strengths of alkali activated mortars were measured, and the correlation between the mechanical properties of hardened mortars and the chemical composition of fly ashes as well as their leaching characteristics was investigated.

Chloride Resistance of Alkali Activated Slag Pastes with Fly Ash Replacement

2016 ◽  
Vol 851 ◽  
pp. 98-103
Author(s):  
Ladislav Pařízek ◽  
Vlastimil Bílek Jr. ◽  
Matěj Březina
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Raw Materials ◽  
High Energy ◽  
Partial Replacement ◽  
Alkali Activated Slag ◽  
Practical Applications ◽  
Chloride Resistance ◽  
Activated Slag ◽  
Alkali Activated

High energy requirements due to producing of Portland cement leads to a tendency to use secondary raw materials or completely new kind of materials. One of the possibilities is using the materials based on alkali activated slag (AAS). In this paper the influence of partial replacement of ground granulated blast furnace slag by fly ash in AAS pastes on mechanical properties and porosity of was investigated. For practical applications it is also necessary to know their resistance to environment such as salty water. Chloride resistance was investigated by setting the experiment as external chloride attack and measuring the changes of mechanical properties, porosity and composition of the pastes.

Mechanical Properties of Alkali Activated Fly Ash Geopolymer Stabilized Expansive Clay

2019 ◽  
Vol 23 (9) ◽  
pp. 3875-3888 ◽  
Author(s):  
Anant Lal Murmu ◽  
Anamika Jain ◽  
Anjan Patel
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Expansive Clay ◽  
Alkali Activated

Physical and Mechanical Properties of Cement Paste Were Used Partially with Fly Ash and Kaolin Waste

2017 ◽  
Vol 866 ◽  
pp. 199-203
Author(s):  
Chidchanok Chainej ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Partial Replacement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lime Water ◽  
Diffraction Patterns ◽  
Iron Mold

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.

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.

Earth-Based Mortars: Mix Design, Mechanical Characterization and Environmental Performance Assessment

2022 ◽  
Author(s):  
Rayane de Lima Moura Paiva ◽  
Adriana Paiva Souza Martins ◽  
Lucas Rosse Caldas ◽  
Oscar A.M. Reales ◽  
Romildo Dias Toledo Filho
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Environmental Impacts ◽  
Calcium Chloride ◽  
Clay Fraction ◽  
Supplementary Cementitious Materials ◽  
Mix Design ◽  
Partial Replacement ◽  
Promising Alternative ◽  
The Earth

The incorporation of sustainable materials in the civil construction sector has grown in recent years to minimize environmental impacts. Among these materials, the use of earth, a local raw material that does not require much energy for its processing, appears as an advantageous and promising alternative. Earth mortars stabilized with natural binders, when compared to conventional mortars, can have technological, economic and environmental advantages. The objective of this work was to develop an earth-based mortar stabilized with mineral binders using a 1:3 binder to aggregate mass proportion, and to evaluate its fresh and hardened state properties, as well as its environmental impacts using Life Cycle Assessment (LCA) with a cradle to gate scope. The selected materials were divided in four groups: (i) cement, hydrated lime, fly ash and metakaolinite (binders), (ii) natural sand and coarse fraction of the earth (aggregates), (iii) calcium chloride and superplasticizer (additives) and (iv) water. In the matrix formulation the clay fraction from earth constituted the majority of the binder. The selection of supplementary cementitious materials as additional binders provided improvements in workability and mechanical properties of the mortar. A mix design was carried out using different cement (5; 7.5 and 10%) and fly ash (11; 13.5 and 16%) mass percentages. The water/binder material ratio, superplasticizer content and calcium chloride content were 0.65; 2% and 1%, respectively. The results showed that an increase in fly ash content combined with a decrease in cement content provided an increase in workability and a decrease in mechanical properties of mortars. Nevertheless, the mechanical performance of the mortars remained above the minimum values prescribed in Brazilian construction codes. From the results analysis it was concluded that partial replacement of cement by fly ash provided greater workability in the fresh state and reduced the environmental impacts of the earth-based mortar.

The Effect of Homogenization Procedure on Mechanical Properties of High-Performance Concrete with Partial Replacement of Cement by Supplementary Cementitious Materials

2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Water Content ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Depth Of Penetration ◽  
Cement Additive

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.

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