الفهرس 
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Abstract
The need to reduce the consumtion of energy and the release of CO2 is
recognized in the portland cement industry and much effort or resources
have been expanded in improving the traditional manufacturing processes.
So, there are important needs to resolve the ecological and economical
problems to solve ordinary portland cement problems like sulfate and
chloride attack. At recylization of solid wastes as GBFS, FA and GCB,
these wastes exposed to obtain binder materials characterized by
resistance to aggressive media , resistance to thermally tratment
temperature, cheaper and more friendly to enviroment than portland
cement.
Different mixes were prepared from GBBFS, FA and GCB using SH and
SSL as alkaline activator. The mixing of the pastes were carried out in a
porcelain mortar for 3 minutes with the required amount of water
containing the activator untile workability is attained. The pastes were
moulded in the 0.5×0.5×0.5 inch moulds and cured in humidifier (100%
R.H) at 25oC and 65oC for 3 days then demoulded; and cured in 100%
relative humidity upto 360 days. Compressive strength, bulk density,
combined water, total porosity and combined slag contents were
measured. The hydration products of some selected samples were
identified by XRD and SEM technique. For elevated thermally treated
temperature, or firing resistance, the specimens cured at 28 days then
dried at 100°C for one day, and then exposed to various elevated
temperatures at (200°C upto 1000°C) in an electric furnace for two hours,
then cooled in furnace closed switch off-to reach room temperature. For
Chapter V: Summary and Conclusion
160
aggressive attack, the specimens are stored under water for 28 days (zero
month), then subjected to 5% MgSO4 or 5% MgCl2 solution. The
specimens are tested at 1, 3, 6, 9 and 12 months.
The durability of some selected mixes in aggressive solution such
as 5% MgSO4 or 5% MgCl2 upto 12 months was studied. The physicochemical, mechanical and microstructure characteristics of pastes were
determined .The effect of aggressive ions was investigated using XRD
and SEM techniques. The total chloride and sulphate contents were
determined for the immersed samples.
from this study the following main conclusions were obtained:
1.physico-chemical and mechanical characteristics
1.1.Alkali Activation of GBFS:
The compressive strength gradually increased with the curing
period for all hardened mixes, due to higher reactivity of
geopolymer slag binder with the formation of successive amounts
of calcium silicate hydrates (CSH), calcium aluminate hydrate
(CAH) and sodium-alumino-silicate hydrated geopolymer gel
(N,C) ASH through the activation process.
The data showed that the compressive strength values improved
with increasing of the Na2O content and heat-treated temperatures
upto 65oC.
Mix S4 gives the highest compressive strength values at all curing
period.
The combined slag of GBFS binders improved with the alkaliactivated content.
The values of the BD improved and the TP decreased with
treatment temperatures and ages.
Chapter V: Summary and Conclusion
161
1.2.Alkali Activation of GBFS-FA:
the synergetic effect of alkali activated and thermally treated
temperatures improved the performance of GBFS-FA binders.
These results proved that the Wn contents of the geopolymer
binders enhanced with increase of Na2O content from 0.5 to 1
mol/kg of binder as seen in behavior of SF3 and SF4 mixes.
the combined slag contents of alkali activated GBFS-FA are lower
than those of GBFS pastes (S1 mix).
The combined slag content decreases by replacement of slag by
50% FA due to the dilution of GBFS in the blends.
1.3.Alkali Activation of GBFS-GCB:
The results showed that the mix containing 100% GBFS (S1) has
higher compressive strength than those of mix containing 50%
GBFS + 50% GCB (SH1) at all hydration ages and has a resenable
compressive strength values as compared with SH2 by increasing
the curing time at 65oC.
An increasing in the compressive strength values was observed in
the case of replacing GBFS by 50% GCB only in case of SSL mass
ratio of 1.0 after all curing ages as shown in mixes SH3 and SH4.
Mix SH4 give the highest compressive strength values at all curing
period.
SEM for geopolymer pastes having 50% GCB (SH4) after 360
days cured at 65oC , is more compact and less pores than 100%
GBFS (S1) . The denser structure was observed due to the higher
Na2O content in the geopolymer mixture; this enhanced the
geopolymerization process and increased the compressive strength.
Chapter V: Summary and Conclusion
162
1.4.Alkali Activation of FA-GCB:
The results showed that the mix containing 100% GBFS (S1) has
higher compressive strength than those of mix containing 50%FA +
50% GCB (HF1 and HF2) at all hydration ages.
The data showed that the compressive strength values improved
with heat-treated temperatures at 65oC as well as by increasing of
the Na2O content upto 1 mol/kg of binder.
The combined slag content of the mixes containing GCB+FA (HF)
mixes lower than slag geopolymer mix at all hydration time up to
360 days.
The combined slag and combined water contents of alkali activated
GCB-FA are lower than that of GBFS paste (S4mix). This is
attributed to the low activity of FA and homra , espically at early
ages of hydration.
1.5.The characteristics of the optimum mixes:
S4 mix specimens prepared using the highest content of sodium
hydroxide (SSL:SH mass ratio of 1.0mol/Kg), showed the highest
compressive strength values at all tested ages in comparison with
other mixes. On the other hand all mixes (SH4, SF4, HF4 and S4)
have higher compressive strength values than those of S1 mix at all
hydration ages.
The results also showed that the replacement of 50% GBFS by
50% GCB (SH4) or 50%FA (SF4) give comparable compressive
strength values to the S4 mix.
Mix S4, which activated and thermally cured at 65oC, showed the
highest combined water values than S1 and give a comparable
values to SH4 but give higher values than SF4 and HF4.
Chapter V: Summary and Conclusion
163
2. Resistance to thermally treated temperatures of alkali activated
slag geopolymer:
Compressive strength of all specimens enhanced by increasing the
elevated treatment temperatures upto 400°C, but when the samples
exposed to thermally treated temperature at 600 °C has caused the
further strength degradation. On the other hand, the increase of the
thermally treated temperatures, upto 800 and 1000oC, an increase
in CS was shown due to the sintering process or solid-state reaction
to produce a ceramic bond of geopolymer ingredients.
The alkali activated slag of mix S4 exhibited the higher values of
the bulk density and less values of the total porosity at all treated
temperature in comparison with the other mixes.
The weight loss showed a sharp significantly increase upto 400°C.
This indicates that Ca(OH)2 is not formed in the alkali activation of
CaO-rich slag in geopolymers despite very high alkalinity.
Further increase in temperature from 800°C to 1000°C, the data
showed another increase in the weight loss of the specimen. The
weight losses of the geopolymers cured at high temperature (65°C),
are greater than the weight losses of the samples cured at (25°C)
3. Aggressive chemical attack:
The CS of OPC pastes increased upto 3 months then reduces up to
12 months
Mix S4 has a higher values of compressive strength than neat OPC
and other mixes, and increased upto 12 months
The total sulphate contents are increased upto 12 months for all
alkali activated slag binders. OPC pastes give a higher values of
the total sulphate and total chloride contents than other mixes.
The data showed that SF4 mix represent the higher durability to the
Chapter V: Summary and Conclusion
164
penetration of the sulfate and chloride ions attack, leading to
formation of a denser structure and enhances the durability to
chloride medium upto 12 months.