Concrete with High Content of Fly-Ash for Common Use in the Czech Republic

2014 ◽  
Vol 1000 ◽  
pp. 190-195
Author(s):  
Hana Sachova ◽  
Petr Huňka ◽  
Jiří Kolísko ◽  
Stanislav Řeháček ◽  
David Čítek
Keyword(s):  
Fly Ash ◽  
Raw Materials ◽  
Concrete Strength ◽  
Waste Product ◽  
Winter Season ◽  
Pozzolanic Reaction ◽  
Building Structures ◽  
Concrete Production ◽  
Increased Strength ◽  
Effective Use

Concrete with high substitute of the cement with fly-ash (FAC) is favourably used for structures with undesirable development of hydration heat or where reduction of the share of Portland clinker in the adhesive provides better resistance of concrete against impacts of acidic aggressive environment. Due to pozzolanic reaction fly-ash participates on formation of cement or adhesive stone and contributes to increased strength of concrete. As the pozzolanic reaction process is gradual its impact on the increased concrete strength is shown within longer time horizon (i.e. after lapse of standard age) and fly-ash concretes are therefore characterized by a short-term low strength which is one of its disadvantages mostly during winter season. However during summer season concretes with partial substitute of cement with fly-ash are beneficial solution for common use even from the aspect of reduced material costs on concrete production. Reduced cement volume in the concrete is nevertheless limited by requirements of ČSN EN 206-1 on concrete composition which is making difficult launch of concrete with higher cement substitutions with fly-ash on the Czech market. FAC allow effective use of the fly-ash, which is otherwise a waste product representing environmental load on spoil heaps as a substitute of clinker, the production of which is also environmentally loading from the power and raw materials aspect. This environmental input of FAC would be hopefully more considered for design of building structures in the future.

The Influence of Particle Size of Cement and Different Additives on the Properties of Portland Cement Pastes

2016 ◽  
Vol 851 ◽  
pp. 104-109 ◽  
Author(s):  
Pavel Šiler ◽  
Iva Kolářová ◽  
Tomáš Sehnal ◽  
Roman Snop ◽  
Tomáš Opravil ◽  
...  
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Portland Cement ◽  
Raw Materials ◽  
Cement Pastes ◽  
Secondary Raw Materials ◽  
Granulated Blast Furnace Slag ◽  
Concrete Production ◽  
Effect Of Particle Size ◽  
Effective Use

The consumption of concrete as a building material is still increasing over the world. Concrete production is closely associated with CO2 and other greenhouse gases emissions. The reduction of these emissions can be achieved by a higher utilization of secondary raw materials in cement mixtures. Particle size is an important factor for more effective use of these materials. This work is focused on the calorimetric determination of the effect of particle size of cement, finely ground granulated blast furnace slag (GBFS), high-temperature fly ash (FA) and fluidized fly ash (FFA) on the Portland cement hydration. Effect of particle size on the hydration of pure cement pastes and pastes with the addition of secondary raw materials is monitored by isoperibolic calorimetry. Other part of this work is aimed on the mechanical properties of resulting materials. The flexural strength and compressive strength were observed after 1, 7 and 28 days of curing.

Quantification of geographical proximity of sugarcane bagasse ash sources to ready-mix concrete plants for sustainable waste management and recycling

2020 ◽  
pp. 0734242X2094537 ◽  
Author(s):  
Gopinath Athira ◽  
Abdulsalam Bahurudeen ◽  
Vijaya Sukumar Vishnu
Keyword(s):  
Fly Ash ◽  
Sugarcane Bagasse ◽  
Raw Materials ◽  
Disposal Site ◽  
Partial Replacement ◽  
Geographic Proximity ◽  
Study Results ◽  
Concrete Production ◽  
Sugarcane Bagasse Ash ◽  
Ready Mix Concrete

As stated in the European Commission’s waste framework directive, the geographic proximity of wastes to the potential recovery/disposal site is of paramount importance in attaining an effective resource recycling paradigm. The global interest in achieving an end-of-waste scenario encourages the recovery of useful products/secondary raw materials from locally available waste materials. Sugarcane bagasse ash is an abundantly available waste (44,200 tonnes day–1) from sugar plants in India which has the potential to be used as a partial replacement to cement in ready-mix concrete plants. Although pozzolanic performance of sugarcane bagasse ash and its ability in reducing the carbon emissions associated with concrete production have been reported in earlier research studies, its use in concrete is hindered due to the lack of availability and accessibility data. In this study, the geographical distribution of sugar plants and the available quantity of sugarcane bagasse ash in India have been determined. In addition, a detailed network analysis using a geographic information system was conducted to quantify the geographic proximity of bagasse ash, fly ash and slag sources to ready-mix concrete plants. The study results indicate that for most of the ready-mix concrete plants in India, the probability of having a bagasse ash source in proximity is higher than the probability of encountering slag/fly ash sources.

The Use of Anthracite Fly Ash for the Production of Autoclaved Aerated Concrete

2012 ◽  
Vol 512-515 ◽  
pp. 3003-3006
Author(s):  
Rostislav Drochytka ◽  
Vit Cerný ◽  
Karel Kulísek
Keyword(s):  
Heat Treatment ◽  
Fly Ash ◽  
Construction Industry ◽  
Raw Materials ◽  
Exothermic Reaction ◽  
Reaction Heat ◽  
Anthracite Coal ◽  
Concrete Production ◽  
Aerated Concrete ◽  
Cellular Concrete

Burning high-quality anthracite coal produces ash with a high content of unburned residues, which in many cases permanently exceeds 20%. These ashes usually contain high levels of amorphous phase providing the pozzolanic activity, this making them particularly useful if potentially applied in the construction industry. Such potential of effective treatment necessitates reducing the content of unburned residues, the best level here being less than 4% w/w. This paper deals with the results of testing heat treatment of fly ashes particularly using the resources of eastern Slovakia. Tests have shown that tested process of heat treatment can safely reduce the content of unburned residues in fly ash whilst maintaining high levels of the glass phase. Raw materials thus modified meet the requirements for the use in cellular concrete production technology with beneficial use of exothermic reaction heat from fly ash treatment in pre-heating the autoclaves.

A Strength Model for Concretes Containing Fly Ash, Blast-Furnace Slag and Silica Fume

1985 ◽  
Vol 65 ◽  
Author(s):  
Edwin R. Dunstan
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Concrete Strength ◽  
Pozzolanic Reaction ◽  
Strength Data ◽  
Production Mechanisms ◽  
Furnace Slag ◽  
By Products

ABSTRACTThis paper describes preliminary a model for the strength of concretes containing industrial by-products such as fly ash, blast-furnace slag, and silica fume. A formula that describes the various strength production mechanisms of these by-products is developed. These materials produce strength by pozzolanic reaction, by latently hydraulic reactions and by self-cementing reactions similar to Portland cement. A method of separating the effect of each mechanism is proposed. A parameter for each of these strength producing mechanisms can be determined from concrete strength data.

Research on the Application of Limestone Powder in Concrete Engineering

2012 ◽  
Vol 174-177 ◽  
pp. 341-344
Author(s):  
Shuang Mei Cao
Keyword(s):  
Fly Ash ◽  
Concrete Strength ◽  
Henan Province ◽  
Limestone Powder ◽  
Fly Ash Concrete ◽  
Composition Materials ◽  
Effective Use

This thesis first analyzes the necessity for the application of limestone powder produced in Lime Ridge from Xixia County, Henan Province. It also tests the concrete performance with different composition materials and does research on the influence of limestone powder on concrete strength by adding limestone powder instead of fly ash in fly ash concrete. It then finds out the reasonable volume of limestone powder to meet the concrete’s performance, in order to guarantee the scientific and effective use of limestone powder in concrete engineering.

scholarly journals High-strength fluoroanhydrite composition

2019 ◽  
Author(s):  
Grigory Yakovlev ◽  
Jadvyga Keriene ◽  
Valery Grakhov ◽  
Rostislav Drochytka ◽  
Anastasiya Gordina ◽  
...  
Keyword(s):  
Water Resistance ◽  
Raw Materials ◽  
Waste Product ◽  
High Strength ◽  
Structure And Properties ◽  
X Ray ◽  
Physico Chemical ◽  
Gypsum Plaster ◽  
Chemical Studies ◽  
Increased Strength

The research studies the properties of a high-strength anhydrite composition based on fluoroanhydrite, a waste product of hydrofluoric acid. To activate fluoranhydrite, Na3PO4 sodium phosphate was added to the composition in an amount of 3% of the mass. The physico-chemical studies of the structure and properties of activated fluoroanhydrite conducted using infrared spectroscopy and X-ray phase analysis showed changes in the composition of the hardened composite, and the study of the fluoroanhydrite microstructure revealed the formation of a denser matrix with the increased strength. An increase in the water resistance of the developed binder matrix was noted. The composition can be used as a cheap substitute for gypsum plaster due to the low prime cost of raw materials, and also contribute to the improvement of the environmental situation in fluoroanhydrite disposal sites.

scholarly journals Application of Fly Ash and Slag Generated by Incineration of Municipal Solid Waste in Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Cong Zeng ◽  
Yan Lyu ◽  
Dehong Wang ◽  
Yanzhong Ju ◽  
Xiaoyu Shang ◽  
...  
Keyword(s):  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Coarse Aggregate ◽  
Coal Fly Ash ◽  
Concrete Strength ◽  
Waste Incineration ◽  
Hydration Reaction ◽  
Mswi Fly Ash ◽  
Concrete Production

As landfill space for the disposal of products of municipal solid waste incineration (MSWI) such as fly ash and slag becomes increasingly scarce, a reduction of disposed material is urgently required. The method of using incineration products in concrete production is explored in this paper through a feasibility study of utilizing fly ash and slag to replace cement and coarse aggregate in appropriate proportions. Results show that C30 concrete optimum replacement rates of fly ash and slag are 30% and 20%, which can meet the minimum strength requirement. The leaching concentrations of Cu, Zn, Pb, Cr, and Cd in MSWI concrete samples are determined to be less than the identification value of solid waste leaching toxicity. Based on scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses, MSWI fly ash has certain dispersion. The particle size of MSWI fly ash is determined to be close to that of the coal fly ash, and the surface morphology is irregular. The main components include SiO2, CaCO3, and Ca2SiO4, and they are similar to those present in the coal fly ash. The slag structure is loose as well as irregular, and its main component is SiO2. The SiO2 and Al2O3 in fly ash and slag participate in the hydration reaction of cement and can increase concrete strength. It is thus confirmed that fly ash and slag generated by waste incineration can be used to replace cement and coarse aggregate in appropriate proportions, and it is an effective method to solve the problem of scarcity of solid waste landfill space.

scholarly journals On the issue of expanding the base of mineral and complex additives for cement concrete

2019 ◽  
Vol 135 ◽  
pp. 01018
Author(s):  
Oleg Tarakanov ◽  
Elena Belyakova ◽  
Varvara Yurova
Keyword(s):  
Building Materials ◽  
High Efficiency ◽  
Materials Science ◽  
Raw Materials ◽  
Hydrate Formation ◽  
High Strength ◽  
Organic Additives ◽  
Cement Concrete ◽  
Concrete Production ◽  
Increased Strength

Modern materials science is characterized not only by the creation of high-strength building materials, but also by using a large number of raw materials and additives that improve the properties of concrete mixtures and concrete. The article considers the possibility of using both old and new generations of complex organomineral additives in concrete production. The nature of the effect of additives on the rheological behavior of cement systems and hydrate formation processes, as well as an assessment of the effect of mineral and organic additives on the composition of hydration products of cement systems, are revealed. Studies have shown that complex additives, which include hyper- and superplasticizers, lead to some slowdown in hydration and crystallization processes. The high efficiency of plasticizing additives helps to reduce water content, which in turn provides increased strength of cement concrete.

scholarly journals Analysis of fly ash from PLTU Asam-Asam as a construction material in terms of its physical and mechanical properties

2019 ◽  
Vol 280 ◽  
pp. 04013
Author(s):  
Irfan Prasetia ◽  
M. Fahmi Rizani
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Material ◽  
Concrete Strength ◽  
Coal Ash ◽  
Physical And Mechanical Properties ◽  
Pozzolanic Reaction ◽  
Test Results ◽  
Replacement Ratio ◽  
Slump Test

Nowadays, PLTU Asam-Asam produced enormous amounts of combustion waste in the form of coal ash. On the contrary, only a little effort has been made to utilize coal ash from PLTU Asam-Asam, especially from the research side. In fact, due to its siliceous material, when reacting with CH in concrete, will form CSH hence improves concrete strength. In this study, in order to analyze the physical and mechanical properties of concrete using fly ash from PLTU Asam-Asam, 54 concrete samples were prepared according to SNI-03-2834-2000. The examination of concrete samples workability was conducted based on the slump test according to SNI 1972:2008. Moreover, the compressive tests were carried out in accordance with SNI 1974:2011. The slump test results show that the pozzolanic reaction of fly ash contributes to the improvement of concrete workability. Furthermore, the variation in w/b ratio was also affecting the results of the slump test. As for the compressive strength, in general speaking, the replacement ratio of 30% of cement with fly ash in concrete could produce concrete strength up to 30 Mpa. It is also important to note that due to the pozzolanic reactions tends to delayed, it is expected that at later ages (above 28 days) concrete with fly ash will gain much more strength compared to ordinary concrete.

Autoclaving Time Influence on Fly Ash Aerated Concrete Compressive Strength and Microstructure

2014 ◽  
Vol 897 ◽  
pp. 301-304
Author(s):  
Ester Helanová ◽  
Rostislav Drochytka ◽  
Radek Janovský
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Hydrothermal Reaction ◽  
Raw Materials ◽  
Concrete Strength ◽  
Use Value ◽  
Environmental Aspects ◽  
Concrete Compressive Strength ◽  
Modern Material ◽  
Aerated Concrete

The fly ash aerated concrete is a modern material combining high use value with environmental aspects of its production. It is mainly an utilisation of secondary raw materials with related minimum consumption of natural resources. The resulting properties the aerated concrete product obtains by autoclaving during which a complete line of calcium hydro silicates are formed due to occurring hydrothermal reaction and tobermorite mineral is the most important one. This mineral has a significant influence principally on aerated concrete strength. This article thus verifies the autoclaving time influence on tobermoritic phase developments and to this related compressive strength of the fly ash aerated concrete.

Sign in / Sign up

Export Citation Format

Share Document