Improvement of Soft Soil Properties Using Dynamic Compaction with Stone Columns: Case Study (AL-Mualla Site-Yeman)

Dynamic compaction was considered as one of a deep compaction method which was used to improve the soil properties. Also it was used to save cost and time in comparison with other methods.The aims of the present studies were to study the improvement and changes in soil properties that occurred in Al-Mualla Site-Yeman using dynamic compaction. The site soils classified as Silty Sand with small boulder with Clayey-Silt layer extend from 2.2 m to 3.2 m deep.Cone penetration test was done before and after treatment process using dynamic compaction for approximately the same two tested boreholes. As a result of the treatment and based on how the soil properties changes, the soil was divided into three zones varied from (1.2 to 5, 5 to 8.6, and 8.6 to 11 m) respectively. Field results show that there was increased in bearing capacity from 80 kN/m2 to 110 kN/m2. Cone penetration test for the first zone increased from (1.2 to 8.35 MN/m2), and from (2.43 to 7.07 MN/m2) for the first and third zone respectively at the first tested borehole and also from (2.05 to 6.8 MN/m2), and (2.14 to 5.0 MN/m2) for the second tested borehole. Also can be noted that the cone penetration test results decreased from (5.22 to 3.77 MN/m2) for the second zone at the first tested borehole, with no change was happening for the second tested boreholes.Also the effect of soil improvement on the settlement value and effective stress distribution was studied theoretically using finite element package PLAXIS2D program. The result shows that the improvement in soil properties leads to decrease in the expected settlement

Mechanical properties of concrete using different types of recycled plastic as an aggregate replacement

AbstractThis study examined the quality of concrete using polyethylene terephthalate (PET) and polypropylene pipe (PEP) as aggregate replacements. In concrete mixtures, PET and PEP replaced up to 15% of the aggregates. Several laboratory tests were conducted to assess the effects of these replacements on the quality of concrete mixtures. Workability, unit weight, modulus of elasticity, compressive strength, indirect tensile strength (splitting), and flexural strength were tested. This study reveals that the two types of plastic waste materials can be successfully used as partial replacements for sand or coarse aggregates in concrete mixtures. PEP reduces workability, whereas PET enhances this material property. A lighter concrete density, up to 10% less than that of the control mixture, was obtained. The use of recycled plastic reduced the compressive strength, tensile strength, and flexural strength by up to 31%, 22%, and 60%, compared with normal concrete, respectively. A finite element model was used to simulate the flexural beam test using the modulus of elasticity obtained from the experimental tests to examine the behavior of normal concrete, PET, and PEP concrete. Dedicated results were obtained using FEs for the failure mode and flexural capacity