خولة حمودي حسان شبر

Najaf-sea quarry is located in Najaf city about 160 km south west of Baghdad the capital of Iraq. It is the main source that supplies track ballast for maintenance of existing railway network and construction of new railway lines in the middle and southern parts of Iraq. Track ballast experience a complex combination of stresses during its service lifetime, primarily from repeated axial loads of the trains in addition to stresses generated from the environmental conditions. The ideal evaluation of suitability of track ballast must be carried out under real field loading conditions, however such field tests are usually costly and time consuming. On the other hand laboratory model tests simulating field loads under limited boundary conditions can provide satisfactory indication about the suitability of the material. The present paper investigates the deformation characteristics of Najaf-sea track ballast, under repeated loading using model tests simulating ballast conditions under a selected track section. A test setup was designed and manufactured capable of applying both monotonic as well as repeated loading on the track section under different conditions. The repeated model tests which simulate as close as possible the field conditions shed the light on the generated settlement, modulus of deformation and degradation of the ballast particles under different repeated loading levels. Statistical analysis in terms of breakage index and repeated applied load revealed satisfactory correlations that help in understanding the overall performance of the ballast material. The results also demonstrate that 4–5 tamping are capable of controlling both the settlement and modulus of deformation of the ballast material.

Al-Qa'im quarry located in Al-Qa'im which is an Iraqi town sited in about (400km) northwest Baghdad the Capital of Iraq, characterizes the main source that supplies track ballast for the maintenance of the existing railway network and construction of the new railway lines in the middle and northern parts of Iraq. Track ballast subjects a complex combination of stresses during its service life time, primarily from the repeated axial loads of the train in addition to stresses generated from the environmental conditions. The ideal evaluation of the behaviour of ballast must be tested under real field loading conditions, however such field tests are usually costly and time consuming. On the other hand, laboratory model tests simulating field loads under limited boundary conditions can provide satisfactory indication about the suitability of the material. This paper investigates the deformation characteristics of Al-Qa'im track ballast, based on repeated load model tests, simulating ballast layer under a certain selected track section. A test setup was designed and manufactured capable to applying both monotonic as well as repeated loading under different cycles and simulated tamping processes. The repeated model tests which simulate as close as possible the field conditions shed the light on the generated settlement, modulus of deformation and degradation of the ballast particles under different repeated loading levels. Statistical analysis in terms of breakage index and repeated applied load revealed satisfactory correlations that assisted understanding the overall performance of the ballast material. The results also demonstrate that 4-5 tamping are capable of controlling both the settlement and modulus of deformation of the ballast material.

Al-Qa'im quarry located in Al-Qa'im which is an Iraqi town sited in about (400km) northwest Baghdad the Capital of Iraq, characterizes the main source that supplies track ballast for the maintenance of the existing railway network and construction of the new railway lines in the middle and northern parts of Iraq. Track ballast subjects a complex combination of stresses during its service life time, primarily from the repeated axial loads of the train in addition to stresses generated from the environmental conditions. The ideal evaluation of the behaviour of ballast must be tested under real field loading conditions, however such field tests are usually costly and time consuming. On the other hand, laboratory model tests simulating field loads under limited boundary conditions can provide satisfactory indication about the suitability of the material. This paper investigates the deformation characteristics of Al-Qa'im track ballast, based on repeated load model tests, simulating ballast layer under a certain selected track section. A test setup was designed and manufactured capable to applying both monotonic as well as repeated loading under different cycles and simulated tamping processes. The repeated model tests which simulate as close as possible the field conditions shed the light on the generated settlement, modulus of deformation and degradation of the ballast particles under different repeated loading levels. Statistical analysis in terms of breakage index and repeated applied load revealed satisfactory correlations that assisted understanding the overall performance of the ballast material. The results also demonstrate that 4-5 tamping are capable of controlling both the settlement and modulus of deformation of the ballast material.

Al-Qa'im quarry located in Al-Qa'im which is an Iraqi town sited in about (400km) northwest Baghdad the Capital of Iraq, characterizes the main source that supplies track ballast for the maintenance of the existing railway network and construction of the new railway lines in the middle and northern parts of Iraq. Track ballast subjects a complex combination of stresses during its service life time, primarily from the repeated axial loads of the train in addition to stresses generated from the environmental conditions. The ideal evaluation of the behaviour of ballast must be tested under real field loading conditions, however such field tests are usually costly and time consuming. On the other hand, laboratory model tests simulating field loads under limited boundary conditions can provide satisfactory indication about the suitability of the material. This paper investigates the deformation characteristics of Al-Qa'im track ballast, based on repeated load model tests, simulating ballast layer under a certain selected track section. A test setup was designed and manufactured capable to applying both monotonic as well as repeated loading under different cycles and simulated tamping processes. The repeated model tests which simulate as close as possible the field conditions shed the light on the generated settlement, modulus of deformation and degradation of the ballast particles under different repeated loading levels. Statistical analysis in terms of breakage index and repeated applied load revealed satisfactory correlations that assisted understanding the overall performance of the ballast material. The results also demonstrate that 4-5 tamping are capable of controlling both the settlement and modulus of deformation of the ballast material.

The highway designers prefer using open-graded, highly permeable layers to overcome the problem of drainage adequacy (Nchrp 1998). So the material specifications should be checked to assure that Hydraulic conductivity, strength, load-distribution, and construction stability requirements are met. The present work purposes is to accumulate main factors effecting on predict the coefficient of Hydraulic conductivity of different stratification layers and gradation of granular materials used as base and subbase courses by constant-head Hydraulic conductivity tests, within the range of validity of Darcy's law for laminar flow condition. Three types and other four types of sand-gravel mixtures are selected as base and subbase course respectively, locally available and currently used in Iraq as pavement construction materials, brought from Al-niba’i quarry near Baghdad, conform to the general specification for road and bridges (SORB, 2003), which based on the BS, AASHTO, or ASTM specifications in gradation and physical properties. Set up depending in this work, comply with Darcy law for laminar flow with porous media and comply with the requirements of ASTM D2434 and AASHTO T215 for determining of Hydraulic conductivity of the granular materials (Al-saoudi and Shubber, 2008, 2012). Where, granular material was speared in layers with compaction sequentially, confirm with required void ratio percent. Water starts to covering prepared sample gradually and slowly until reach 20 cm height above it, then samples left for 24hr to ensure saturation. A hydraulic gradients create of (i= 0.2, 0.25, and 0.3). The rate of flow was checking each 20 sec, constant rate indicating the validity of the steady state flow. The samples were tested at different voids ratio (e1/e2= 0.6, 0.75, 1.0, 1.25, &1.5) and thickness percent (T1/T2= 0.5, 0.66, 1, 1.5, 2) for stratified layers.

This study presents an attempt of experimental study on the effect of adding asphalt emulsion and Portland cement on the engineering properties of sand poorly graded river soil used as subgrade soil in pavement construction. The soil brought from sides of Al-Kufa River in Najaf state middle west of Iraq. Asphalt emulsion used in this study is that manufactured for surfacing and cold paving proposes. While Portland cement is that used in construction building. Percent of adding are (0, 3, 6, 9, 12 and 15) % by weight. Properties of soil studied and presented in this paper are compaction, optimum water content, CBR, and direct shear. Results showed that the adding of asphalt emulsion and cement increase the dry density in different rate. While the optimum water content decrease with increasing asphalt emulsion and increase with increasing cement added. Direct shear of soil stabilized with cement is higher than both natural soil and that stabilized with asphalt emulsion. CBR values showed the same trend of direct shear test results.