Mohammed Kadum Muhialdin Abdalzahra Fakhraldin

The presence of gypsum in soils causes significant changes in the behavior and alters the properties of these types of soils. Gypsum and anhydrite rocks are often found in many countries of the world in extensive deposits. It was known in Greek as Gypsosa, in German as gips (which could be probably derived from Greek) and in Latin as gypsum. Large area in middle and west of Iraq is classified as a gypseous soil. This paper aims to study the benefit of using Netlon CE121 geogrid as reinforcing material on CBR (California Bearing Ratio) which is adopted as an indication for treatment. A laboratory tests were performed on a gypseous soil samples to study the effect of the first layer location (u) of geogrid and soaking on CBR are studied. 4, 15 and 30 days are adopted as a period of soaking. CBR corresponding to 14 kN/m3 is adopted as a reference value to make the comparisons. The results show that the use of geogrid reinforcement increase the value of California Bearing Ratio (CBR) and the location of first layer of geogrid under the surface have a large influence on CBR, the reliable depth is 0.15D where D is the diameter of CBR mold. CBR value for the optimum point increased almost two times when compared with unreinforced soil. Also CBR decrease when the period of soaking increases for unreinforced and reinforced soil. The experimental results shows that the ultimate bearing capacity increase when CBR increase for unreinforced and reinforced soil.

Manufacturing process disposable results in huge amounts of waste as undesirable materials and influence the environmental adversely by increasing pollutions. One of these wastes is cement kiln dust (CKD) which is produced by cement plants in all over the world. Utilization of CKD in construction industry is very important as it consumes enormous amounts of CKD, decreases the pollutant impacts on environmental, save further costs of embedding process, and employing CKD as cheap material in civil engineering applications. In this regard, the present study devoted to using CKD to increase the bearing capacity of sandy soil. Several studies have been achieved in this respect by mixing CKD as percentages with the soil. In this work, a new method is introduced by lining sandy soil with CKD in layers of specified thickness. The factors have been discussed; thickness of layer, number of layers, and layers positions. The best position of the CKD layer was specified with direct shear test. The soil was tested in four cases which included 0.15B, 0.2B, 0.25B, and 0.5B, B is the width of the box in direct shear test, and the thickness layer was specified to 0.1B. The results indicate that the best position of the lining layer is 0.5B, and the angle of the internal friction in this case increased about 2.41 times.

Abstract: Recently, a fast evolution of structures in urban centres attended by a dearth of beneficial areas has pushed the specialists to recover soil properties in order to carry the applied loadings of structures. One of the technology of soil advancement is use of admixtures. In Iraq, the tires Reclaim are produced by Ministry of Industry and Metals with low costs because it is considered as a by-product of tires manufacturing. This paper concerned with investigates the use of Reclaim as additive to soil. The effect of Reclaim on California Bearing Ratio (CBR) of sandy soil is studied. Many of laboratory tests was carried out on the original soil (0% Reclaim) and using 0.5%, 2%, 4% Reclaim by the weight of soil. A CBR laboratory tests on soil samples without and with Reclaim under 4 days soaking condition to simulate the long-term soaking case. The results show that the dry unit weight of sandy soil increase when the Percent of Reclaim increase. Also, for all cases (0%, 0.5%, 2% and 4%) Reclaim, CBR increase as the dry unit weight increase for each case. The main important conclusion conducted that CBR decrease when the percent of Reclaim increase, thus, use of Reclaim do not improve the soil to carry the applied loads, the increment in CBR varies from 7.6% to 68.8%.

There are several uses of granular soils in civil engineering works such as but not limited to under foundations structures, subbase course of roads, unpaved roads and soil embankments. This research attempts to overcome the problems of low-quality (by means of strength) of granular soil by enhancing California Bearing Ratio (CBR) test by utilizing geogrid. The research aim's to investigate the potential benefits of using the geogrid to improve CBR of granular soil. The results of tests showed that the granular soil under study was inferior than the materials comply on class C of Iraqi specifications for granular soil material. On the other hand, using of geogrid type Tensar SS2 at 0.15H (where H the total thickness of granular material samples) improves extremely the CBR value of the granular soil as it is increased by about three times in comparison with untreated soil.

The soil properties are an important parameter for architectural and structural design of structures. Al-Najaf city in Iraq is a famous tourist destination, so in the last one decade a number of multistory buildings, bridges, highways, schools, hospitals, etc. have been constructed. This study investigates the properties of the soil to give a base data, which can be used for the future construction design. The physical and chemical soil properties were investigated and analyzed. The results show that the most of the soil is classified as a sandy soil with little fines having a cohesion varying from 0 to 13.2 kPa and angle of internal friction varying from 26.3 to 41.2 degrees; while liquid and plastic limits (LL and PL) vary from 21 to 29% and from 11 to 15% respectively. The low values of LL and PL for the soil of western locations increase towards the eastern locations. The values of maximum dry density and optimum moisture content vary from 17.5 to 19 kN/m3 and 8.6 to 13.2% respectively. The studies also show that the organic content and sulphate content have a low varies between 1 and 2.9% and 2.2 and 2.7% respectively while the gypsum content varies from 13.6 to 28.3%. The assemblages of gypsum soil concentrated in the west side of the city.

The industrial by product materials which are generated from cement manufacturing must be managed responsibly, such as the other industries, to insure a clean and safe environment. Cement Kiln Dust (CKD) is a significant by product material of the cement manufacturing process. The majority of CKD is recycled back into the cement kiln as a raw feed. Other beneficial applications were then adopted such as agricultural soil enhancement, base stabilization for pavements, wastewater treatment and waste remediation. This research introduces a new method to upgrade the performance of the granular materials which are normally used in subbase courses. The proposed method can be characterized by adding CKD lining within this layer. CKD lining was with 0.1H (0.1 of the total thickness of granular material samples) and posted in different locations from the top of the specimen i.e. 0.1, 0.15, 0.2, 0.25 and 0.5H. The mechanical properties, by means of California Bearing Ratio (CBR) test, has been improved significantly as it increased almost three times when 0.1H of CKD lining placed on 0.2H in comparison with untreated material. Also, this improvement can reduce the total asphalt concrete layers by almost 30% in accordance to the pavement structural analysis which is conducted in the present study.