الفهرس 
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Abstract
Due to increasing concerns about environmental pollutions especially caused by production of Ordinary Portland cement, many authors studied the synthesis of new binding materials instead of cement especially by using solid waste. This was carried out by using the alkaline activation process for some solid wastes, in other words geopolymerization process.. Therefore, the aim of this investigation to study the physico-chemical characteristics of geopolymer cement prepared from some solid wastes .
The wastes used in this study were ground granulated blast-furnace slag (GGBFS), homra (H), marble dust (MD) and granite powder (GP). The alkaline activators used in geopolymerization process were (NaOH, 10M) and (Na2SiO3, 6M). The activators used in five different ratios. GGBFS was used as blank material which replaced by homra, MD and GP with different ratios.
Each mix was first mechanically mixed in the dry state in ball mill to attain complete homogeneity. The geopolymer cement pastes were prepared by mixing each dry mixture with the liquid alkaline activators, without addition of water or superplasticizer. After complete mixing the resulted pastes were molded into one inch cubic moulds. The moulds containing the pastes were then cured at about 100% relative humidity for the first 24 hours at room temperature (25 ˚C ± 1) in order to attain the final setting of the specimens. The hardened geopolymer cement pastes were then removed from the moulds and cured at ~ 100% RH up to 90 days. The applied time intervals were 3, 7, 14, 28 and 90 days. Samples were cured at ~ 100% RH up to 90 days for examining the physicochemical and mechanical characteristics.
In this study the physicochemical and mechanical characteristics of geopolymer cement were examined via the following tests:
1. Determination of setting times.
2. Determination of the compressive strength.
3. Determination of the water absorption.
4. Determination of mass change percentage.
In addition the phase composition and microstructure are tested for some selected samples using infra-red spectroscopy (FTIR), x-ray diffraction (XRD) and scanning electron microscopy (SEM).
The study of thermal resistance and durability against sulfate ions for some geopolymer mixes are also included in this thesis.
The main observations for obtained results can be summarized as follows:
Physico-chemical and Mechanical characteristics of the GGBFS-Homra Geopolymer Cement:
1. The values of the compressive strength of the GGBFS-Homra paste activated with 1:1 LSS:LSH was higher than those of the paste with another ratios.
2. The results of the water absorptions for the geopolymer cement paste made by replacement of GGBFS by homra was in agreement with compressive strength results, but in some cases the water absorption result depends on the filling effect of homra due to high Blaine surface area of homra (5053 cm2/gm).
3. The values of percentage of mass change in all GGBFS- Homra geopolymer cement were increased with curing time.
4. The values of setting times controlled by many factors such as LSS:LSH ratio and percentage of Homra replaced GGBFS.
5. Firing has a negative effect on compressive strength of geopolymer cement.
6. X-ray diffraction analysis showed that the main phases of the hydration products were CSH , CAMS and calcite for the geopolymer cement in normal curing. And showed that the main phases of the hydration products were CAMS, quartz and calcite for the geopolymer cement after curing in MgSO4 solution. And showed that the main phases of the hydration products were sodium calcium silicate, calcite and quartz after firing at 200 and 600 oC.
7. The results of sulfate attack resistance indicate that the substitution of GGBFS with Homra increase resistance to MgSO4 attack.
8. FTIR spectroscopy indicated the formation of different hydration products and also presence of carbonation reaction.
9. Microstructure investigation using scanning electron microscope showed that the paste containing GGBFS only have more dense structure of gel-like and fibrous crystals of calcium silicate hydrates than that in the paste containing GGBFS with Homra.
Physico-chemical and Mechanical characteristics of the GGBFS-MD geopolymer cement
1. The values of the compressive strength of the blended mixes with MD were lower than those of the blank mix at all ages of hydration.
2. The results of the water absorption confirmed that the replacement of GGBFS with MD led to decrease in hydration rate.
3. The values of percentage of mass change in all GGBFS MD geopolymer cement were increased with curing time.
4. X-ray diffraction analysis showed that the main phases of the hydration products were CSH, CAMS, sodium calcium silicate, calcite and quartz for the geopolymer cement in normal curing, and after curing in MgSO4 solution. And showed that the main phases of the hydration products were sodium calcium silicate, calcite and quartz after firing at 200 and 600 oC.
5. The values of setting times controlled by many factors such as LSS:LSH ratio and percentage of MD replaced GGBFS.
6. The results of sulfate attack resistance indicate that the substitution of GGBFS with MD increase resistance to MgSO4 attack.
7. Firing has a negative effect on compressive strength of geopolymer cement.
8. FTIR spectroscopy indicated the formation of different hydration products and also presence of carbonation reaction.
9. Microstructure investigation using scanning electron microscope showed that the paste containing MD have less calcium silicate hydrates.
Physico-chemical and Mechanical characteristics of the GGBFS-GP geopolymer cement:
1. The values of the compressive strength of the blended mixes with GP were lower than those of the blank mix at all ages of hydration.
2. The results of the water absorption confirmed progress of geopolymerization process and accumulation of hydration products which fill the open pores.
3. X-ray diffraction analysis showed that the main phases of the hydration products were CSH, CAMS, sodium calcium silicate, calcite and quartz for the geopolymer cement in normal curing, and after curing in MgSO4 solution. And showed that the main phases of the hydration products were sodium calcium silicate and calcite after firing at 200 and 600 oC.
4. Firing has a negative effect on compressive strength of geopolymer cement.
5. Microstructure investigation using scanning electron microscope showed that the paste containing GP tends to the formation of less calcium silicate hydrates.
6. FTIR spectroscopy indicated the formation of different hydration products and also presence of carbonation reaction.
7. The values of percentage of mass change in all GGBFS- GP geopolymer cement were increased with curing time.
8. The values of setting times controlled by many factors such as LSS:LSH ratio and percentage of GP replaced GGBFS.
9. The results of sulfate attack resistance indicate that the substitution of GGBFS with GP increase resistance to MgSO4 attack.
The main conclusions could be derived from this study can be summarized as follows:
1. The 1 LSS(6M):LSH(10M) is the optimum ratio for activation GGBFS replaced by Homra, MD or GP.
2. Both initial and final setting times affected by ratio of alkaline activators.
3. Firing especially at high temperature (600 oC) has a bad effect on geopolymer cement.
4. Resistance of geopolymer cement against sulfate attack was increase by increasing the amount of Homra, MD or GP that replaced GGBFS .
5. Mix H1.3 show the highest compressive strength while, mix G2.5 show the lowest compressive strength.
6. The replacement of GGBFS with 10%Homra increase the compressive strength while, substitution of GGBFS with 20% or 30% Homra decrease compressive strength.
7. The replacement of GGBFS with MD or GP decrease the compressive strength.