Some natural resources such as gravel are not renewable, therefore, it is necessary to reduce the use of such resources and replace them with other recycled, economic, and environmentally friendly materials. Recycled crushed concrete aggregates demolished from old buildings and blocks of waste concrete can be used to replace the natural aggregates. The present study focused on using recycled crushed concrete in improvement the chemical and geotechnical properties of soft soil having undrained shear strength of 6.78 kPa. The soft soil samples were mixed with 5, 10, and 15% of crushed concrete. The blocks of waste concrete are grinded by mills to get crushed concrete which passing sieve no. 4. Such aggregates are lighter than natural aggregates and provide a good deformation modulus when mixed with soil. In Iraq, there are hundred thousand tons of concrete blocks used as fences and now considered wastes after removing these security fences, so it's important to interest from recycling of such materials to be used in the improvement wide region of soft soils in Iraq. The results of tests showed increasing the undrained shear strength of soft soil by 175-193.5% and reduced the compressibility of soft by 25-31% measured in terms of compression index.

Based on the results of standard penetration tests (SPTs) conducted in Al-Basrah governorate, this research aims to present thematic maps and equations for estimating the bearing capacity of driven piles having several lengths. The work includes drilling 135 boreholes to a depth of 10 m below the existing ground level and three standard penetration tests (SPT) at depths of 1.5, 6, and 9.5 m were conducted in each borehole. MATLAB software and corrected SPT values were used to determine the bearing capacity of driven piles in Al-Basrah. Several-order interpolation polynomials are suggested to estimate the bearing capacity of driven piles, but the first-order polynomial is considered the most straightforward. Furthermore, the root means squared error (RMSE) for all suggested polynomials are roughly the same. The production of thematic maps demonstrates the variation in bearing capacity of driven piles over the entire territory of Al-Basrah governorate in correlation with different depths. The results of the statistical equations showed that there is good agreement with those obtained from the SPT data. When compared with the observed values from SPT, the allowable bearing capacity results for the driven piles ranged from (−3 to +38)%. The main results of this study showed a variation of 30% between calculated and estimated values of bearing capacity of driven piles for all lengths of piles at a 95% confidence interval.

The problematic soils have complex and irregular behavior such as gypseous soils, which concentrated mainly in the dry and semi-dry regions in the world. In Iraq, the gypseous soils cover about 30 to 35% of its total area in the west desert and extended to the southern parts of Iraq. The gypseous soils experience sudden collapse upon wetting. The present paper focuses on studying the effects of nano silica fume (NSF) on the collapsibility and shear strength of gypseous soil before and after soaking. Also, this study, the influence of NSF on the chemical and physical characteristics of gypseous soil have been investigated. A gypseous soil sample obtained from Al-Najaf Sea has gypsum content of 42%. The gypseous soil samples are mixed with three percentages of nano silica fume (1, 2, and 4) % calculated as ratio of the dry mass of soil to measure their influence on the geotechnical characteristics of soil samples. The collapse potential of gypseous soil is reduced with increasing the content of nano silica fume. Also, increasing the content of NSF and curing time resulted in increasing the shear strength of soil samples.