This study aims to assess the impact of time on sawdust usage to enhance the behavior of the clay used in landfills. The soil used in this paper was brought from Büyükçekmece region / Istanbul. Four proportions (1, 2, 3 and 5) of the sawdust were added as a percentage of the dry weight of the soil. Soil-sawdust mixtures were compacted with the optimum water content corresponding to each percentage and samples were extracted. The extracted samples were divided into two groups, the immediate tests were performed on the first group while the second group was kept in special containers for long-term tests after 90 days. A series of undrained unconsolidated triaxial tests (UU) and unconfined compression tests (UCS) were performed on the specimens and compared with the row soil, in the immediate tests, the results from the UU triaxial test showed that the undrained shear strength was increased as the sawdust content increased and then decreased, it was conducted that the optimum sawdust content was 3%, it was increased the undrained shear strength by (39.5%) and (41.44%) for UU triaxial and Unconfined compression tests respectively. After 90 days of the curing period, it found that 2% is the optimum sawdust content, it was increased the undrained shear strength by (202.51%) and (176.64%) for UU triaxial and unconfined compression test respectively. In the immediate and long-term tests, the coefficient of permeability increased by (66.66) and (94.44%) as the sawdust increased from 0 to 5 % respectively. Sawdust increases the hydraulic conductivity of the clay. It can be concluded that the sawdust usage has a remarkable effect on the shear strength of the clay for both immediate and long-term tests.
One of sustainable concrete engineering criteria deals with founded new alternative materials can be used in concrete mixes or structures. The objective of this study is to develop normal strength concrete using local crushed Al-Ma'mora stones and to evaluate the effect of a new coarse aggregate on mechanical and physical properties of produced concrete, also compared with normal (conventional coarse aggregate) concrete mix. In general, a new concrete mix shows higher than strength of normal concrete due to low porosity, particularly, when crushed coarse aggregate is used. However, the compressive strengths of new concrete mix using Al-Ma'mora and conventional (reference) aggregates are improved by 20%, due to texture modification. Also, the flexural strength of this concrete was higher than the reference concrete by 51.7%, and the splitting strength Almaamora stone concrete was higher than the reference concrete by 42.4% .
The stability of the embankment’s slopes is a critical aspect of geotechnical engineering and it is essential to guarantee the effectiveness of the factor of safety to prevent any potential failures in the slope both during and post-construction. The current study consists of two parts; the first part is the study of the behavior of the geogrid-encased granular columns and their interaction with the soil at the shear surface generated by the slippage of the soil, while the second part is a study of the stability of slopes by changing several factors, including the area replacement ratio (Ar %) of the granular columns, the angle of the embankment slope (β), and different elastic modulus (Eg) of geogrid on the stability of an embankment. About 90 analyses were conducted on a clayey sand embankment over a clayey layer. The area replacement ratios (Ar %) were changed by using different values of the diameter of the column; from 50 to 100 cm. The angle of the embankment slope was changed from 28 to 36 degrees. Furthermore, three different values, 0.12, 2.625, and 6.552 GPa, of modulus of elasticity were used. The results show that increasing the modulus of elasticity of the geogrid increases the normalized shear strength and decreases the lateral displacement in the column. Furthermore, the factor of safety was increased as the stiffness ratio between the geogrid and the materials increased. However, the factor of safety was noted to decrease when the angle of the embankment slope was increased.
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