Abstract: Several review papers exist in literature related to the concrete containing mineral admixtures; however this paper reviews the durability characteristics of the concrete containing fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK) and rice husk ash (RHA). Durability related properties reviewed include permeability, resistance to sulfate attack, alkali-silica reaction (ASR), carbonation, chloride ion penetration, freezing and thawing, abrasion, fire, acid and efflorescence. From review of existing literature, it is found that permeability of concrete depends upon the content of alumina in mineral admixtures, i.e. higher the alumina content, lesser the permeability which results higher resistance to sulfate and chloride ion penetration. Highly reactive mineral admixtures prevent more ASR and reduce efflorescence. The carbonation increases with the mineral admixtures because higher water binder ratio and lesser content of portlandite in concrete due to pozzolanic reaction. Mineral admixtures require air entrainment except MK and RHA for better resistance to freezing and thawing.
Abstract: Strength recovery effect from the residual-state of shear is not well address in scientific literature. Torsional ring shear strength recovery tests on kaolin clay using rest periods up to 30 days are performed at the effective normal stress 100kN/m2. Test results shows that recovered strength measured in the laboratory is slightly noticeable after rest period of 3 days, but recovered strength lost after very small shear displacement. This paper mainly focused on the strength recovery phenomenon from the residual strength of kaolin clay based on torsional ring shear test results. Mechanisms of recovered strength are also discussed.
Abstract: Paleoclimate was reconstructed by the clay mineral
assemblages of shale units of Pabdeh (Paleocene- Oligocene), Gurpi
(Upper Cretaceous), Kazhdumi (Albian-Cenomanian) and Gadvan
(Aptian-Neocomian) formations in the Bangestan anticline. To
compare with clay minerals assemblages in these formations,
selected samples also taken from available formations in drilled wells
in Ahvaz, Marun, Karanj, and Parsi oil fields. Collected samples
prepared using standard clay mineral methodology. They were
treated as normal, glycolated and heated oriented glass slides. Their
identification was made on X-Ray diffractographs. Illite % varies
from 8 to 36. Illite quantity increased from Pabdeh to Gurpi
Formation. This may be due to dominant dry climate. Kaolinite is in
range of 12-49%. Its variation style in different formations could be a
marker of climate changes from wet to dry which is supported by the
lithological changes. Chlorite (4-28%) can also be detected in those
samples without any kaolinite. Mixed layer minerals as the mixture
of illite-chlorite and illite-vermiculite-montmorillonite are varied
from 6 to 36%, decreased during Kazhdumi deposition from the base
to the top. This result may be according to decreasing of illite
leaching process. Vermiculite was also determined in very less
quantity and found in those units without kaolinite. Montmorillonite
varies from 8 to 43%, and its presence is due to terrestrial
depositional condition. Stratigraphical documents is also supported
this idea that clay mineral distribution is a function of the climate
changes. It seems, thus, the present results can be indicated a possible
procedure for ancient climate changes evaluation.
Abstract: The alumosilicate ceramics with mullite crystalline phase are used in various branches of science and technique. The mullite refractory ceramics with high porosity serve as a heat insulator and as a constructional materials [1], [2]. The purpose of the work was to sinter high porosity ceramic and to increase the quantity of mullite phase in this mullite, mullite-corundum ceramics. Two types of compositions were prepared at during the experiment. The first type is compositions with commercial alumina and silica oxides. The second type is from mixing these oxides with 10, 20 and 30 wt.%. of kaolin. In all samples the Al2O3 and SiO2 were in 2.57:1 ratio, because that was conformed to mullite stechiometric compositions (3Al2O3.2SiO2). The types of alumina oxides were α-Al2O3 (d50=4µm) and γ-Al2O3 (d50=80µm). Ratios of α-: γ-Al2O3 were (1:1) or (1:3). The porous materials were prepared by slip casting of suspension of raw materials. The aluminium paste (0.18 wt.%) was used as a pore former. Water content in the suspensions was 26-47 wt.%. Pore formation occurred as a result of hydrogen formation in chemical reaction between aluminium paste and water [2]. The samples were sintered at the temperature of 1650°C and 1750°C for one hour. The increasing amount of kaolin, α-: γ-Al2O3 at the ratio (1:3) and sintering at the highest temperature raised the quantity of mullite phase. The mullite phase began to dominate over the corundum phase.
Abstract: The acidity of different raw Jordanian clays
containing zeolite, bentonite, red and white kaolinite and diatomite
was characterized by means of temperature programmed desorption
(TPD) of ammonia, conversion of 2-methyl-3-butyn-2-ol (MBOH),
FTIR and BET-measurements. FTIR spectra proved presence of
silanol and bridged hydroxyls on the clay surface. The number of
acidic sites was calculated from experimental TPD-profiles. We
observed the decrease of surface acidity correlates with the decrease
of Si/Al ratio except for diatomite. On the TPD-plot for zeolite two
maxima were registered due to different strength of surface acidic
sites. Values of MBOH conversion, product yields and selectivity
were calculated for the catalysis on Jordanian clays. We obtained that
all clay samples are able to convert MBOH into a major product
which is 3-methyl-3-buten-1-yne (MBYNE) catalyzed by acid
surface sites with the selectivity close to 70%. There was found a
correlation between MBOH conversion and acidity of clays
determined by TPD-NH3, i.e. the higher the acidity the higher the
conversion of MBOH. However, diatomite provided the lowest
conversion of MBOH as result of poor polarization of silanol groups.
Comparison of surface areas and conversions revealed the highest
density of active sites for red kaolinite and the lowest for zeolite and
diatomite.
Abstract: The electrochemical coagulation of a kaolin
suspension was investigated at the currents of 0.06, 0.12, 0.22, 0.44,
0.85 A (corresponding to 0.68, 1.36, 2.50, 5.00, 9.66 mA·cm-2,
respectively) for the contact time of 5, 10, 20, 30, and 50 min. The
TSS removal efficiency at currents of 0.06 A, 0.12 A and 0.22 A
increased with the amount of iron generated by the sacrificial anode,
while the removal efficiencies did not increase proportionally with
the amount of iron generated at the currents of 0.44 and 0.85 A,
where electroflotation was clearly observed. Zeta potential
measurement illustrated the presence of the highly positive charged
particles created by sorption of highly charged polymeric metal
hydroxyl species onto the negative surface charged kaolin particles at
both low and high applied currents. The disappearance of the
individual peaks after certain contact times indicated the attraction
between these positive and negative charged particles causing
agglomeration. It was concluded that charge neutralization of the
individual species was not the only mechanism operating in the
electrocoagulation process at any current level, but electrostatic
attraction was likely to co-operate or mainly operate.
Abstract: Ranong province has the best kaolin, and it is the most
useful of all the clay types used in ceramic making. Until recently,
there has been only one community business making ceramics in
Ranong province. And this business could not build the mix of body
and glaze from their raw material without assistance. Considering
these problems, this research is aimed to test the composition of
ceramic body and glaze which suit. Kaolin from Ranong is the raw
material which these search focuses on. All other raw materials use in
the investigation will come from southern Thailand, kaolin and
limestone from Ranong province, ball clay from Surat Thani
province, white sand from Songkhla province, and feldspar from
Nakhon Si Thammarat province. Results can be used to develop the
efficiency of industrial production which in return will enhance the
business process.
Abstract: Biodiesel production with used frying by
transesterification reaction with methanol, using a commercial
kaolinite thermally-activated solid acid catalyst was investigated.
The surface area, the average pore diameter and pore volume of the
kaolinite catalyst were 10 m2/g, 13.0 nm and 30 mm3/g, respectively.
The optimal conditions for the transesterification reaction were
determined to be oil/methanol, in a molar ratio 1:31, temperature 160
ºC and catalyst concentration of 3% (w/w). The yield of fatty acids
methyl esters (FAME) was 92.4% after 2 h of reaction. This method
of preparation of biodiesel can be a positive alternative for utilizing
used frying corn oil for feedstock of biodiesel combined with the
inexpensive catalyst.
Abstract: A comprehensive program of laboratory testing on a
compacted kaolin in a modified triaxial cell was perform to
investigate the influence of hydraulic hysteresis on effective stress in
unsaturated soils. The test data are presented on a range of constant
suction shear tests along wetting and drying paths. The values of
effective stress parameter χ at different matric suction were
determined using the test results. The effect of hydraulic hysteresis
phenomenon on the effective stress was observed. The values of
effective stress parameter χ obtained from the experiments were
compared with those obtained from the expressions proposed in
literature.
Abstract: In this work, grinding or microcutting tools in the form of pellets were manufactured using a bounded alumina abrasive grains. The bound used is a vitreous material containing quartz feldspars, kaolinite and a quantity of hematite. The pellets were used in glass grinding process to replace the free abrasive grains lapping process. The study of the elaborated pellets were done to define their effectiveness in the grinding process and to optimize the influence of the pellets elaboration parameters. The obtained results show the existence of an optimal combination of the pellets elaboration parameters for each glass grinding phase (coarse to fine grinding). The final roughness (rms) reached by the elaborated pellets on a BK7 glass surface was about 0.392 μm.
Abstract: The use of additions in cement in manufacturing,
mortar and concrete offers economic and ecological advantages. Cements with additions such as limestone, slag and natural
pouzzolana are produced in cement factories in Algeria. Several studies analyzed the effect of these additions on the physical and
mechanical properties as well as the durability of concrete. However,
few studies were conducted on the effect of local metakaolin on
mechanical properties and durability of concrete. The main purpose
of this paper is to analyze the performance of mortar and concrete with local metakaolin. The preparation of the metakaolin was carried
out by calcination of kaolin at a temperature of 850 °C for a period of 3 hours. The experimental results have shown that the rates of
substitutions of 10 and 15% metakaolin increases the compressive
strength and flexural strength at both early age and long term. The durability and the permeability were also improved by reducing the
coefficient of sorptivity.
Abstract: This paper is concerned with the study of mineralogy
and engineering characteristics of soil materials derived from the
eastern part of Nile Delta. The clay minerals of the studied soil by
using X- ray diffraction are mainly illite (average 72.6 %) and
kaolinite (average 2.6 %), expandable portion in illite-smectite mixed
layer (average 7 %). Smectite is more abundant in fluviatile clays,
whereas kaolinite is more abundant in lagoonal clays. On the other
hand, illite and illite-smectite are more abundant in marine clays. The
geotechnical results show that the soil under study consists mainly of
about 0.3 % gravel, 5 % sand, 51.5 % silt and 42.2 % clay in average.
The average shrinkage limit attains 11 % whereas the average value
of the plasticity index is 23.4 %. The free swelling ranges from 40 %
to 75 % and has a value of 55 % giving an indication about the
inadequacy of such soil under foundations.
From a construction point of view, the soil under investigation
poses many problems even under light foundations due to the
swelling and shrinkage. Such swelling and shrinkage is due to the
high content of soil materials in the expandable clay minerals of illite
and smectite. Based on the results of the present and earlier studies,
trial application of soil stabilisation is recommended.
Abstract: The present work deals with the stabilisation of
organic clay using hydrated lime. Artificial organic clays were
prepared by adding kaolin and different humic acid contents. Results
given by physical testing show that the presence of humic acid has a
drawback effect on the untreated organic clay. The decrease in
specific gravity value was accompanied by a decrease in dry density
and plasticity of clay at higher humic acid contents. Significant
increase in shear strength at 7 days of curing period is observed in the
lime-treated samples up to 5% lime content. However shear strength
of lime-treated organic clay decreases at longer curing periods. The
results given by laboratory testing is further verified by
microstructure analysis. Based on the results obtained in this study, it
can be concluded that the presence of more than 1.5% humic acid
reduces significantly the efficiency of lime stabilization in organic
clays.
Abstract: Pharmaceutical industries and effluents of sewage treatment plants are the main sources of residual pharmaceuticals in water resources. These emergent pollutants may adversely impact the biophysical environment. Pharmaceutical industries often generate wastewater that changes in characteristics and quantity depending on the used manufacturing processes. Carbamazepine (CBZ), {5Hdibenzo [b,f]azepine-5-carboxamide, (C15H12N2O)}, is a significant non-biodegradable pharmaceutical contaminant in the Jordanian pharmaceutical wastewater, which is not removed by the activated sludge processes in treatment plants. Activated carbon may potentially remove that pollutant from effluents, but the high cost involved suggests that more attention should be given to the potential use of low-cost materials in order to reduce cost and environmental contamination. Powders of Jordanian non-metallic raw materials namely, Azraq Bentonite (AB), Kaolinite (K), and Zeolite (Zeo) were activated (acid and thermal treatment) and evaluated by removing CBZ. The results of batch and column techniques experiments showed around 46% and 67% removal of CBZ respectively.