Experimental Evaluation of Construction Waste and Ground Granulated Blast Furnace Slag as Alternative Soil Stabilisers

In this study, the effect of ground granulated blast furnace slag (GGBFS) and recycled construction waste (CW) on bentonite clay stabilisation were investigated. The unconfined compressive strength (UCS) of specimens was evaluated with different combinations of GGBFS and CW over various curing periods. A series of micro analysis tests consisting of scanning electron microscope, energy dispersive spectrometer and X-ray diffraction were also conducted to determine the microstructural arrangement and mineralogical effect of the stabilisation treatment. The UCS results showed an increment in strength after introduction of GGBFS and CW and the longer curing period produced more pronounced results. The optimum additive ratio was calculated as 5 % of slag and 20 % of construction waste under all curing conditions. The micro analytical results also indicated formation of structural bonds between admixtures and bentonite in stabilised specimens, as slag crystals and bentonite particles were observed to occupy the cavities and vesicles on the construction waste grains. However, the experimental data shows that the strength improvement is not significant with the addition of only construction waste.     

The effect of specimen diameter size on uniaxial compressive strength,P-wave velocity and the correlation between them

Estimation of uniaxial compressive strength (UCS) by P-wave velocity (V_P) is of great interest to geotechnical engineers in various design projects. The specimen diameter size is one of the main factors that influence rock parameters such as UCS and V_P. In this study, the diameter size of specimens that effect UCS and V_P is investigated. Moreover, the correlation between UCS and V_P are examined via empirical analysis. For this purpose, 15 travertine samples were collected and core specimens with a diameters size of 38, 44, 54, 64 and 74 mm were prepared. Then, uniaxial compressive strength and P-wave velocity tests were conducted according to the procedure suggested by ISRM (1981). It is concluded that the diameter size of the specimen has a significant effect on UCS and V_P. Moreover, it was found that the best correlation between relevant parameters obtained for the specimen diameter of 38 mm.     

Impact of Reservoir Permeability,Permeability Anisotropy and Designed Injection Rate on CO2 Gas Behavior in the Shallow Saline Aquifer at the CaMI Field Research Station,Brooks, Alberta

Natural Resources Research - Carbon capture and storage is part of Canada’s climate change action plan to reduce greenhouse gas emissions. The Containment and Monitoring Institute Field...     

Antenna design and implementation for the future space Ultra-Long wavelength radio telescope

In radio astronomy, the Ultra-Long Wavelengths (ULW) regime of longer than 10 m (frequencies below 30 MHz), remains the last virtually unexplored window of the celestial electromagnetic spectrum. The strength of the science case for extending radio astronomy into the ULW window is growing. However, the opaqueness of the Earth’s ionosphere makes ULW observations by ground-based facilities practically impossible. Furthermore, the ULW spectrum is full of anthropogenic radio frequency interference (RFI). The only radical solution for both problems is in placing an ULW astronomy facility in space. We present a concept of a key element of a space-borne ULW array facility, an antenna that addresses radio astronomical specifications. A tripole–type antenna and amplifier are analysed as a solution for ULW implementation. A receiver system with a low power dissipation is discussed as well. The active antenna is optimized to operate at the noise level defined by the celestial emission in the frequency band 1 ? 30 MHz. Field experiments with a prototype tripole antenna enabled estimates of the system noise temperature. They indicated that the proposed concept meets the requirements of a space-borne ULW array facility.     

Formulation of the Caspian Sea’s legal regime using a joint zone approach

The legal regime of the Caspian Sea has been determined under Treaties 1921 and 1940 by and between Iran and former Soviet Union. In fact, we are neither to explain it nor to determine. As understood from the provisions therein, the exploitation and use of the Caspian Sea by both countries are based on the Condominium. However, there is a 10-nautical mile strip as exclusive fishing areas which have been allocated to the states under the 1940 treaty. It means that Soviet Union and Iran may benefit the marine livings resources out of that strip on an equal manner. This right also includes the seabed and underlying bed. So, the legal regime of this sea may be based on a 10-nautical mile exclusive region for all five states and the remaining part as common and joint area under an agreement until an explaining and supervising organization is established to exploit and supervise over living and non-livings resources.     

Time effects on dynamic soil properties under random excitation conditions

Two types of clayey soils, a kaolinite and a bentonite, were tested using a resonant column apparatus under random excitation conditions. The concept of root mean square (rms) strain was utilized for the purpose of strain calculations during random loading. The conventional estimator of the transfer function was used for random vibration analysis. The effect of confinement duration (at a constant pressure) on dynamic soil properties, namely damping and shear modulus, was evaluated. The results indicate that for both cohesive soils, the effect of time was less pronounced during random vibration than sinusoidal loading at the same rms strain. This effect is however more pronounced when the peak shearing strain of sinusoidal loading is considered. Furthermore, time effects were more pronounced at low strain levels than at high strain levels.     

Neogene and quaternary volcanism of the Bijar Area (Western Iran)

In the Bijar region (Western Iran) two distinct volcanic cycles have been recognized. The first, of Upper Miocene age, consists of high-K cale-alkaline volcanic rocks interpreted as final products of the cale-alkaline Tertiary phase of central Iran. The second volcanic cycle, mostly of Pleistocene age (0.5–1.3 m.v.) consists of undersaturated, mainly potassic, alkaline products. As the lavas of this last phase are slightly fractionated, the chemical differences shown by these rocks have been interpreted as primitive features related to the physical conditions governing the partial melting in the mantle and/or the mantle heterogeneity. In a volcanic center (Sarajukh volcano) contemporaneous basic and acid magmas have been found, and interpreted as derived from two different and independent sources. The alkaline basic volcanism is considered as an expression of disjunctive processes that have affected the western margin of the Iranian plate after the Pliocene.     

Assessment of copper,cobalt and zinc contaminations in soils and plants of industrial area in Esfahan city (in Iran)

This paper discusses the artificial groundwater recharge effect of high-infiltration basins. For this purpose, the hydrogeological parameters of the study area are collected to construct a conceptualized physical model. The TOUGH2 numerical simulation software is then used to simulate the infiltration behavior of an artificial recharge into an underground aquifer. Four wells (MW-1, MW-2, MW-3, and MW-4) are observed at the field site, after which the groundwater levels are compared with the simulation results. It is found that good agreement exists between the observed and numerical data for MW-1 and MW-2. However, the observed groundwater level in MW-3 is higher than the simulated level. We also find that MW-3 is at the edge of the artificial recharge lake, and that the high groundwater level may well be the result of a portion of the infiltration load following the well border into the well screen. Conversely, the groundwater level in MW-4 is found to be lower than in the simulated well due to local permeability in the well location. Finally, the numerical results predict that the groundwater level will attain a steady state at approximately 47 h after the onset of infiltration.     

Strength behavior and microstructural characteristics of tropical laterite soil treated with sodium silicate-based liquid stabilizer

Although the effects of nontraditional stabilizers on the geotechnical properties of tropical soils has been the issue of investigation in recent years, the micro-structural characteristics of nontraditional soil additives and in particular selected additive (TX-85) have not been fully studied. Nontraditional soil stabilization additives are widely used for stabilizing marginal materials. These additives are low-cost alternatives to traditional construction materials and have different compositions. They also differ from one another while interacting with soil. In line with that, it was the objective of this research to investigate the strength properties and physicochemical mechanisms related to tropical laterite soil mixed with the liquid stabilizer TX-85. Macro-structure study, i.e., compaction, and unconfined compression strength test were used to assess the engineering and shear properties of the stabilized laterite soil. In addition, the possible mechanisms that contributed to the stabilization process were discussed using various spectroscopic and microscopic techniques such as X-ray diffractometry (XRD), energy-dispersive X-ray spectrometry, scanning electron microscopy, and Fourier transform infrared spectroscopy. From engineering point of view, the results indicated that the strength of TX-85 stabilized laterite soil improved significantly. The degree of improvement was approximately four times stronger than natural soil after a 7-day curing period. The XRD showed no crystalline products (gel form). Moreover, weathering effects were obvious in TX-85 treated samples in most of clay minerals’ peak intensities. These effects were reduced especially for kaolinite mineral inside the soil with curing time.