29 Haziran 2009 Pazartesi

The usage of fly ash at beton production

70'ies are the stage when demand for energy and enviromental avareness increases dramatically.
These increases caused to increase the production capacity of coal fired pp although
environmental problems caused by coal used at pp.
The usage of "flue ashs" at production phrasees especially construction, agriculture and chemical
sectors with and excellent results are increasingly going on at present has firstly applied in USA
and spreed out trought of the world in a short time,
The most economic results and serious technical benefits optained at cement and concrete sectors,.
The utilization of ash as an industrial disposal and the usage of concrete production as an
improver of the quality has started to be applied in at the and of 1990''s in Turkey,
All of the Coal fired power plaints produce ash suitable to standarts in Europe occupied by cement
factories and production of many typies of cements except portland cement strongened by flue ash
are higly increased.
Only 4 of all coal fired pp dispose ash suitable to use as addition all the others are not usable
according to standarts of asm., tse639, tse450
The ash disposed .from Seyitömer, Çatalağzı, Tunçbilek and Soma pp''ies canbe used only after
seperation.
The usage possibilty of the ashes depend on the quality, homonenity, the type of combustion and
the filtration of the coal fired at pp.,
The structure of flu ash is sferical and spongy and particual size varies between 1-200 |im. 85 % of
the flue ash'ies Chemical composition is made of SiO2, A12O3, Fc2O3, CaO ve MgO. The particules
of ash show senoferic and dermosfiic characteristic and they are decomposed by high temperature.
Flue ash contains low calcium in their minéralogie composition reacts with calciumhydroxide in.
their humid environments and shows their connective feature.,
That is to say they are "puzolanic". Flue ash contains high calcium has connevtive features by
themselves because of amorphous components in their chemical structure and so.
Specific surface of flue ash is vary from 1700 to 5000 enr/g, The size of ash produced from, pp
never changes If there isn't any change of manufacture condtion or row material's of the1 pp,
Ash accumulated, at elecro filters or seperated is appropriate for using with concrete and cement.
The dencity of flue ash avaragely is 800 kg/m3,.
The more its fine particule size the much its usage for cementing. The flue ash sized over 3500
blain can be directly sent, to mixing from mill. Since there is no need for grinding and drying flu
ash lowers the producing cost. Concretes produced with cements prepared with flue ash shows
decrease in hydrotion temeperatre, and shows considerable increase in. processing and endurance,.
Cement factories use flu-ash in poduction process increase the capacity at the same time.
It is possible to switch to use flu-ash at cocrete est.ablih.men.ts in a. short time by preparing many
prescriptions directly with pç or pkç
Advantages of the usage flu-ash in ready-made concrete,
218
56. Türkiye jeoloji Kurultayı
56ik Geological Congress of Turkey
A. Resistance of concrete increases higly to compare with portland-cement and this increase
lasts till 400 days(figure 1).
B. Prevents fittings-corrosion/donati korozyonu dute to its feature of filling the cavity
C. Prevents the splits in concrete as its lowering featute of the hydration. temeprature.
D. Cause to a conciderable increase in ready-made concrete
E.. Decrease some the water necessity of concrete.
K. Increase the insulation a little.
L. Increase the process rate of concrete
M, Couse the concrete pumps work, properly at managing and increase the lasting time of
parts exposed to corrosion.
N. Prevent the wrinkle
O. Stop the vomiting and dissociating of concrete.
The transporting, stock and adding into concrete of flu-ash is same as cement,...
It is possible to use it as cement for a specified proportion or to use it as fine materilas(agrega)..
The best result obtained for experiments carried out at laboratuvaries while they used for both as
cement and fine agregga.
ön the other sides flu-ash cab be used at/as:
a) brick production.
b) light-concrete production
c) with injection
d) stabilation of ground.
e) filling material
as increasingly .
' Althoug its usage at maximum rates in. the world flu-ash unfortunately is used quite under avarage
rates in Turkey.
The utilization of an industrial disposal and make it benefical for economy.»
Lowering the production cost by economy saving of energy during mar and cement production.
.Affirmative assistance for the "hazır beton" that directly affects the life standarts by final usage of.
Are the technical topics in. our country as an ear.htqua.ke teritory and economic difficulty.

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