Characterization of Canadian fly ashes and their relative performance in concrete

1987 ◽  
Vol 14 (5) ◽  
pp. 667-682 ◽  
Author(s):  
G. G. Carette ◽  
V. M. Malhotra
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Air Entrainment ◽  
Relative Performance ◽  
Hardened Concrete ◽  
Freezing And Thawing ◽  
Fly Ashes ◽  
Wide Range ◽  
Pozzolanic Properties

Eleven Canadian fly ashes were characterized and evaluated for their relative performance in concrete. Characterization included the determination of mineralogical composition, chemical composition, physical characteristics, and pozzolanic properties. The relative performance of each fly ash in concrete was evaluated through determination of the following properties of fresh and hardened concrete: slump, air content, bleeding, setting time, strength, modulus of elasticity, drying shrinkage, creep, and freezing-and-thawing resistance.The results indicate a wide range of chemical, physical, and pozzolanic properties for the fly ashes investigated. In spite of this, all the fly ashes studied are shown to be suitable for use in concrete. They affect, however, the properties of fresh and hardened concrete in different ways, and this should be taken into account when proportioning concrete containing these fly ashes. Key words: fly ash, concrete, pozzolanic activity index, bleeding, setting time, air-entrainment, strength, creep, shrinkage, freezing and thawing.

The Influence of W/C Ratio and Superplasticizer Type on Porosity of Concrete with Air-Entraining Cement with Fly Ash

2018 ◽  
Vol 279 ◽  
pp. 266-270
Author(s):  
Beata Łaźniewska-Piekarczyk
Keyword(s):  
Fly Ash ◽  
Fresh Concrete ◽  
Air Entrainment ◽  
Hardened Concrete ◽  
Research Results ◽  
Concrete Mix ◽  
European Standards ◽  
New Generation ◽  
Air Entrained Concrete

The research results of stability of air-entrainment of concrete acc. PN-EN 480-1 in case of innovate air-entraining multi-component cement CEM II/B-V is presented in the paper. The influence of PCE, naphthalene and phosphonamidite based superplasticizers and w/c ratio: 0.45, 0.50 and 0.55 on air-entrainment and consistency of fresh concrete mix was investigated. The research results indicated that with increasing w/c ratio the air-entrainment of concrete increases. Moreover, in case of an increase in the degree of liquidity of the air-entrained concrete made of participation of the innovative, air-entraining multi-component cement CEM II/B-V, first and new generation superplasticizers based on modified naphthalene, and then modified phosphonamidite should be used. PCE based superplasticizer cause the too high air-entrainment of concrete. The research results proved, that the porosity of hardened concrete meets the European standards for frost-resistant concrete.

Determination of Slag and Fly Ash Content in Hardened Concrete

1995 ◽  
Vol 17 (1) ◽  
pp. 55 ◽  
Author(s):  
RD Hooton ◽  
RD Hooton ◽  
CA Rogers
Keyword(s):  
Fly Ash ◽  
Ash Content ◽  
Hardened Concrete

Relationship Between Pozzolanic Activity and Chemical and Physical Characteristics of Selected Canadian Fly Ashes

1985 ◽  
Vol 65 ◽  
Author(s):  
R. C. Joshi ◽  
V. M. Malhotra
Keyword(s):  
Fly Ash ◽  
National Standard ◽  
Fly Ashes ◽  
Bureau Of Reclamation ◽  
Supplementary Cementing Materials ◽  
University Of Calgary ◽  
Fly Ash Utilization ◽  
The University ◽  
Pozzolanic Properties ◽  
The U.S

Raymond E. Davis and his associates appear to have coined the term “fly ash” in 1937. Following the pioneering studies by the U.S. Bureau of Reclamation for the Hungry Horse Dam, the use of fly ash for massive hydroelectric structures increased rapidly in the U.S., with ASTM issuing the first standard in 1954. In 1982, Canada issued a National Standard, CAN 3-A23.5-M82, entitled “Supplementary Cementing Materials and Their Use in Concrete Construction.” Because of the increasing interest in fly ash utilization, Canada Centre for Mineral and Energy Technology (CANMET) initiated research in the area of supplementary cementing materials in the early 1970's and has since published several comprehensive reports on the subject [1,2]. At the University of Calgary, we are studying Canadian fly ashes and their use in concrete, through an investigation of the physical, chemical, mineralogical and pozzolanic properties of fly ashes from fourteen sources across the country. We report here preliminary results from this study.

scholarly journals Dielectric Study on Fly Ash Blended Cement

2009 ◽  
Vol 6 (1) ◽  
pp. 231-236 ◽  
Author(s):  
G. Sivakumar ◽  
K. Mohanraj ◽  
S. Barathan
Keyword(s):  
Fly Ash ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Blended Cement ◽  
Dielectric Measurement ◽  
Dielectric Study ◽  
Cement Composites ◽  
Distilled Water ◽  
Fly Ashes ◽  
Solid Ratio

In this paper, the hydration behaviour of ordinary portland cement (OPC) and fly ash blended cement (10, 25 and 40%) replaced by two different fly ashes (FA) were investigated. The samples were hydrated with distilled water (DW) in water to solid ratio 0:4 and its setting time and dielectric measurement are carried out. Results of the study found that the fly ash blended cement composites have slow hydration than OPC during early stages (up to 24 h).

Experimental Research on Coal Gangue Grouting Material for Gob Filling

2013 ◽  
Vol 357-360 ◽  
pp. 1158-1166
Author(s):  
Tian Feng Gu ◽  
Zhong Di Sun ◽  
Feng Tao Luo ◽  
Kang Guo ◽  
Ya Ming Liu ◽  
...  
Keyword(s):  
Fly Ash ◽  
Compression Strength ◽  
Raw Materials ◽  
Setting Time ◽  
Blended Cement ◽  
Coal Gangue ◽  
Activation Process ◽  
Initial Setting Time ◽  
Wide Range ◽  
Coal Gob

Grouting fill is one of the main methods of coal gob treatment. The grouting properties directly affect the effect of grouting treatment. Cement-fly ash grout is widely used in the treatment of coal gob. But in many gob grouting fill projects, due to the lack of fly ash, we need to look for other low-cost grouting materials. Study was made through laboratory experiment on the properties of cement-coal gangue materials used for the gob grouting. In this paper, the correlation of water-solid ratio, cement content, admixture, concretion compression strength, setting time, viscosity, water segregation rate and hardening rate is discussed in the case of use of large gangue content cement. The test results show that compared with the grout not go through the activation process, the blended cement grout mixed with coal gangue powder activated by low temperature and mechanical crushing has high concretion compression strength. Water glass has a great effect on the viscosity, initial setting time and final setting time, which can be used to adjust the grout properties to accommodate grouting environment requirements. This grout has the advantage of wide range sources of raw materials, and can be used to solve the lack of fly ash and gangue resource utilization problems.

Alkali Activation of HCFA Mixtures with Aluminosilicate Additives - Mechanical Characteristics

2018 ◽  
Vol 761 ◽  
pp. 96-99 ◽  
Author(s):  
Ionna Papayianni ◽  
Fotini Kesikidou ◽  
Stavroula Konopisi
Keyword(s):  
Fly Ash ◽  
Mechanical Characteristics ◽  
Setting Time ◽  
Weight Ratio ◽  
Alternative Methods ◽  
Alkali Activation ◽  
Fly Ashes ◽  
Volume Deformation ◽  
High Calcium ◽  
Alumino Silicate

Over the last years, the increasing need of cost saving and environmental protection has led to finding alternative methods and materials in construction. One of these methods is the alkali-activation, which can transform alumino-silicate binders, like siliceous fly ashes, blast furnace slags, into useful materials. On the other hand, little focus has been given to study the potential uses of high calcium fly ashes (HCFAs), which are also produced in Europe and constitute the half of total fly ash output.In this paper, a calcareous fly ash (F) from Agios Demetrios power plant in Greece was studied in combination with different alumino-silicate materials such as pozzolan, diatomite and brick dust in order to improve their physico-mechanical characteristics. Pastes were mixed with an alkaline activator, which consists of a sodium silicate solution and sodium hydroxide solution 10M. The weight ratio of NaOH:Na2SiO3was 1:1. At the fresh state, setting time of the mixture was measured after mixing. Prismatic specimens were matured at different temperature conditions (25°C for 2 days and 65°C for 2 days). The samples were tested under flexural and compressive strength at the ages of 2, 7 and 28 days. Volume deformation and open porosity were also determined.

scholarly journals Investigation of Portland cement composites containing high amounts of different kinds of fly ashes

2019 ◽  
Author(s):  
Iwona Wilińska ◽  
Barbara Pacewska ◽  
Wojciech Kubissa
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Setting Time ◽  
Cement Composite ◽  
Fly Ashes ◽  
Cement Pastes ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Lower Heat ◽  
The Impact

Utilization of fluidized fly ash in cement composite is problematic, e.g. because of its changeable chemical composition and increased water demand of the mixture. However, this kind of by-product shows some self-cementing properties, which may be beneficial for low-cement mixtures. The article compares the impact of various kinds of fly ashes, i.e. fluidized fly ash and conventional one, and their mixtures on hydration of fly ash–cement compositions in relation to properties of final material. The amount of fly ash in the binder was 50 wt%. Calorimetry, thermal analysis (TG/DTG) and infrared spectroscopy were used. Compressive strength and water absorption of hardened composites were also registered. It was found that both fly ashes exhibit delay effect in fly ash-cement pastes which causes extension of initial setting time and lower heat released compared to the reference without fly ash. At later hydration days, fluidized fly ash develops higher pozzolanic activity than conventional one. Compositions with fluidized fly ash show better compressive strength compared to those containing conventional one. Mixing of different materials of high and low activity (fluidized and conventional fly ash in this case) seems to be a good way for creation of new cement replacement material.

A Comprehensive Characterization and Determination of Fly Ashes in Indonesia Using Different Methods

2015 ◽  
Vol 754-755 ◽  
pp. 320-325 ◽  
Author(s):  
Januarti Jaya Ekaputri ◽  
Muhammad Bahrul Ulum ◽  
Triwulan ◽  
Ridho Bayuaji ◽  
Tri Eddy Susanto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Power Plants ◽  
Ordinary Portland Cement ◽  
Activity Index ◽  
Chemical Characterization ◽  
Fly Ashes ◽  
Physical Chemical ◽  
Comprehensive Characterization

This paper presents an observation on fly ash quality in East Jawa, Indonesia. The ash samples were collected from 16 fly ashes produced by some Indonesian power plants. The samples are majority categorized as class F fly ashes with good pozzolanic characteristics according to the standard. The samples were examined for their physical, chemical and mechanical properties with compression test. The test was conducted by making some mortars and paste containing fly ash as cement replacement in accordance with three methods. The compressive strength results were compared with the control specimens made from ordinary Portland cement to obtain a strength activity index (SAI). The results showed that physical properties of fly ash influenced the mechanical properties of mortars more than those showed by chemical characterization.

scholarly journals The composition of the organic and inorganic matter of the Siliceous fly ashes as part of their usefulness in technologies of building materials

2016 ◽  
Vol 32 (1) ◽  
pp. 71-88
Author(s):  
Ewa Strzałkowska
Keyword(s):  
Adverse Effect ◽  
Fly Ash ◽  
Water Demand ◽  
Building Materials ◽  
Fly Ashes ◽  
Porous Particles ◽  
X Ray ◽  
Freeze Thaw ◽  
Inorganic Matter ◽  
Pozzolanic Properties

Abstract Nowadays in Poland around 18 mln tons of energy wastes are produced every year. The utilization method of wastes depends principally on their physicochemical properties. Siliceous fly ashes which have pozzolanic properties which advantageously influence on cement properties, are mainly used in production of cement. The results of studies of the phase composition of the different grain classes of the siliceous fly ash were presented in this article. The minerals: mullite and quartz as well as magnetite, hematite and calcite were identified on the base of thermal analysis, mikroscopic observation and X-ray diffractometry examination. Significant participation in the composition of investigated fly ashes have also fragments of unburned coal. They present different morphological forms depend on the porosity degree. The following forms were distinguished: cenospheres, networks, inertynite massive and porous, detritus. Porous particles accumulate mainly in the coarser grain class and are represented primarily by cenospheres and networks. Their content may have an adverse effect on any further applications of fly ash, so as it is necessary to separation of this class. This will reduce water demand and increase the freeze-thaw resistance of mortar and concrete containing fly ash.

Sign in / Sign up

Export Citation Format

Share Document