bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the sintering temperature on the microstructure and superconducting properties of MgB2 bulks manufactured by the field assisted sintering technique
Authors: Matthews G A B , Santra S , Ma R , Grovenor C R M , Grant P S , Speller S C
Published: March 2020

Magnesium diboride (MgB2) bulk superconductors may have practical applications as permanent magnets owing to their ability to trap larger fields than conventional ferromagnets and a transition temperature of 39 K that make them attractive for use in cryogen-free systems. Unlike the cuprate high temperature superconductors, grain boundaries in MgB2 act as pinning sites not weak links, and so show good current carrying ability in polycrystalline samples. This enables the materials to be processed using standard ceramic processing methods which are scalable to large diameters and mass production. The maximum trapped field in bulk superconductors scales with the critical current density (Jc
) of the material as well as the radius of the sample. To obtain the highest possible Jc
values in MgB2 at high fields requires the bulk materials to be fully dense but fine-grained material, and possibly with a nano-scale distribution of non-superconducting impurity particles to further enhance pinning. Field assisted sintering technology (FAST) is a rapid process for obtaining dense ceramics from materials like MgB2 which are difficult to sinter with conventional pressure-less techniques. Rapid heat treatments are attractive both from a manufacturing point of view and because the total time that the sample is held at high temperature is short, limiting grain coarsening. In this paper, we report a systematic study of the influence of processing temperature on microstructure and superconducting properties of MgB2 bulks manufactured using FAST. We conclude that processing temperatures above 1000 °C are required to obtain materials that have sufficiently high electrical connectivity to generate large magnetic moments. However, the intrinsic (intragrain) Jc
values in MgB2 are better in the samples processed at 900 °C owing to their finer scale microstructures and the MgB2 lattice being more defective.
Layer-dependent band engineering of Pd dichalcogenides: a first-principles study
Authors: Feng Liang-Ying , Villaos Rovi Angelo B. , Huang Zhi-Quan , Hsu Chia-Hsiu , Chuang Feng-Chuan
Published: March 2020

Among the families of transition metal dichalcogenides (TMDs), Pd-based TMDs have been one of the less explored materials. In this study, we investigate the electronic properties of PdX2 (X = S, Se, or Te) bulk and thin films. The analysis of structural stability shows that the bulk and thin film (1 to 5 layers) structures of PdS2 exhibit pyrite, while PdTe2 exhibits 1T. Furthermore, PdSe2 exhibits pyrite in bulk and thin films down to the bilayer. Most surprisingly, PdSe2 monolayer transits to 1T phase. For the electronic properties of the stable bulk configurations, pyrite PdS2 and PdSe2, and 1T PdTe2, demonstrate semi-metallic features. For monolayer, on the other hand, the stable pyrite PdS2 and 1T PdSe2 monolayers are insulating with band gaps of 1.399 eV and 0.778 eV, respectively, while 1T PdTe2 monolayer remains to be semi-metallic. The band structures of all the materials demonstrate a decreasing or closing of indirect band gap with increasing thickness. Moreover, the stable monolayer band structures of PdS2 and PdSe2 exhibit flat bands and diverging density of states near the Fermi level, indicating the presence of van Hove singularity. Our results show the sensitivity and tunability of the electronic properties of PdX2 for various potential applications.
Plasmon drag effect with sharp polarity switching
Authors: Ronurpraful T , Keene D , Noginova N
Published: March 2020

The generation of significant photocurrents observed in plasmonic metasurfaces is interesting from a fundamental point of view and promising for applications in plasmon-based electronics and plasmonic sensors with compact electrical detection. We show that photoinduced voltages in strongly modulated plasmonic surfaces demonstrate a highly asymmetric angular dependence with polarity switching around the plasmon resonance conditions. The effects are tentatively attributed to coupling between localized and propagating plasmons.
Implication of Yield Lines Theory in Method Three of the ACI Code for Two-Way Reinforced Concrete Slabs
Authors: Ali Al-Ahmed Ali Hussein , Kadhim Al-Shamaa Mushriq Fuad , Ali Hasan Hussein
Published: March 2020

Reinforced concrete slabs are one of the most important and complicated elements of a building. For supported edges slabs, if the ratio of long span to short span is equal or less than two then the slab is considered as two-way slab otherwise is consider as one-way slab. Two-way reinforced concrete slabs are common in use in reinforced concrete buildings due to geometrically arrangement of columns suggested by architects who prefer a symmetric distribution of columns in their plans. Elastic theory is usually used for analysis of concrete slabs. However, for several reasons design methods based on elastic principles are limited in their function. Correspondingly, limit state analysis offers a powerful technique for considering such matter. The Yield Lines Theory, which is one of limit state analysis based on expected failure criteria of slabs. The assumed failure criteria is termed by a pattern of yield lines, along that the reinforcement has yielded and the location of which counts loads and boundary conditions. This paper deals with comparison of Method 3 for two-way slabs that was provided by the ACI Code and exact derivation of this method by the Yield Lines Theory. Total of nine cases of slabs that have been described by method three are studied and evaluated by plastic analysis assumptions of the yield lines theory. The results are summarized in terms of proposed formulae that derived according to the Yield Lines Ttheory, which could be used as an alternative method for design of two-way reinforced concrete slabs in the ACI Code.
Effects of steel fibers on flexural strength and impact resistance for self-consolidating concrete plates
Authors: Mohammed Ahlam Sader , Jaber Ali Attiea , Abbas Sura Amoori
Published: March 2020

Self-Consolidating Concrete (SCC) can be considered as a major innovative satiric expansion in the future of concrete materials and technology during the recent three decades. It has evolved to make adequate compaction with easy concrete placement in constructions, which have overcrowded the restricted zones and reinforcement. This research aims to experimentally study the effect of steel fibers volumetric ratio (Vf
) and effect of chicken wire in enhancement of the behavior of the normal strength SCC. Two types of SCC concrete mixes were prepared and cast for this purpose. One of them was normal strength SSC to serve as a reference mix, while 0.75 % of steel fibers was used in the second one. Slump-flow test, L-box, J-ring and V-funnel tests had been done to investigate the properties of fresh SCC. Compressive strength of the reference SCC was about (33.5MPa) and for 0.75% steel fibers SCC was about (39.7MPa). In addition to that, six identical plate’s specimens of (400×400×20) mm were cast and tested to study the effect of steel fibers and chicken wire on the impact load resistance and flexural load of SCC. Results show that the impact load resistance for steel fibers SCC concrete had been increased by about 60% compared with the reference normal strength SCC mix, while an increase in impact load resistance for SCC of about 50% was gained by using chicken wire mesh. It was noted that the use of 0.75% steel fibers-SCC and chicken wire-SCC plates show an increase in impact resistance and flexural strength by about 20% and 2% compared to the reference normal strength SCC, respectively. The results also indicate that using steel fibers is useful in holding up the formation of transverse cracks and providing affirmative restraint to the successive growth of cracks of plate’s specimens.
Structural Evaluation for Iraqi Ministry of Trade Building Exposed to Fire During 2003 War
Authors: Abbas Aamer Najim , Abdul-Hussein Wameedh Ghassan , Ghani Zghair Luma Abdul
Published: March 2020

Existing concrete structures may, for a variety of reasons, be found to be unsatisfactory. This could manifest itself by poor performance under service loading in the form of excessive deflections, cracking or inadequate ultimate strength and changing the main function. In such circumstances, there are two possible solutions i.e. demolish and rebuild or carryout a program of repair and strengthening. In this investigation, the structural evaluation and suggested repairing works were studied for Iraqi Ministry of Trade building, the building was exposed to fire, vandalism and looting during the war on Iraq at 2003. The building consists of twelve stories, ten stories have area about 1428m2 and about 1150 m2 area of middle and basement stories. Each story has height of 3.5m. The structure of building consists of one way ribbed slab with 900mm slab thickness and 0.15×0.7m rib sectional dimensions. The columns have dimensions 0.6×1.2m and height 3.5m. The girders, ribs, floors and columns were peeled and decayed, there are a several cracks wider than 0.4mm distributed on the beams and floors and several columns, the concrete floors were destroyed and that caused appearance of steel reinforcement, parts of concrete of column at the second floor were destroyed and the longitudinal reinforcement steel buckled outside dragging the transverse reinforcement, a high possibility of reduction in concrete strength caused by the fire effects happened during 2003 war but the steel dose not affected by the fire because of the concrete cover which protected reinforcement. From this investigation, there is no serious damage in the sense that it is imperative to demolish the building and re-create. The damage in the building, as indicated in this study require some repairs, known in the field of rehabilitation through chemical additives and steel structures are additional materials available in local markets. It necessary to minimize the additional dead loads and the use of Limestone partitions in their implementation Gypsum Board partitions or imported light partitions.
Flexural behavior of composite open web steel joist and concrete slab
Authors: Abduljabbar Marwah Sami , Hamood Mohammed J. , Abdulsahib Wael Shawky
Published: March 2020

Experimental research has been carried out to study the behavior of composite open web steel joists under monotonic loading. Four composite joists were fabricated with two types of web members and span-to-depth ratios were tested. The concrete slab 400 mm wide, and 90 mm overall depth overlaid on a corrugated steel sheet. The composite system was simply supported over 3000 mm span and subjected to a uniformly distributed loading. Test results are presented in terms of slip between composite slab and the top chord of steel joist, load-deflection and load-strain relations. Based on the experimental results, it can be concluded that lowering span/depth ratio has a significant effect on failure pattern with increase in ultimate capacity about 8%. Additionally, the results show that using double angles web type has only a little influence on deflection but increased ultimate capacity about 10% over similar composite joist with rounded bars web.
Seismic Vulnerability of Rural Masonry Buildings After 2019 Acıpayam Earthquake, Denizli, Turkey
Authors: Güler Kadir , Sütçü Fatih , Sarı Ali
Published: March 2020

Turkey is an earthquake-prone country, and moderate earthquakes hit Acipayam town of Denizli city, located in the western part of Turkey on March 20, 2019 (Mw-5.5). The region is seismically active and, in the past, several earthquakes based on historical archives hit the same region, and some recent modern recordings are available. The March 20 earthquake caused significant damage in the villages of Acipayam, Denizli, where the majority of buildings are masonry buildings, while, the typical building type is cut-stone, adobe and brick masonry-type buildings. The existing buildings suffered damages due to poor building material quality, inadequate design, and detailing. Connection of floor slabs to façade walls are poorly implemented, where in-plane and out-of-plane failures are observed very commonly. Another primary reason for the damage is the poor mortar quality used between masonry units, which lead to masonry walls damages again under in-plane and out-of-plane effects. The most recent Turkish Seismic Code dated 2018, includes a comprehensive chapter on masonry buildings. The general damage observations from Acipayam Earthquake evaluated according to the requirements given in the code and with the lessons taken from past earthquakes, as well.
Structural behaviour of SCC continuous deep beam strengthened with carbon fiber NSM and hybrid techniques
Authors: Al-Bdari W J , Al-Bayati Nabeel , Al-Shaarbaf A. S.
Published: March 2020

In this research, results of an experimental investigation on the shear strengthening of normal SCC continuous concrete deep beam are presented. A total of twelve continuous deep beams were cast and tested. The aim of this paper is to study the effect of carbon fiber reinforced polymers (CFRP|) through Near Surface Mounted (NSM) and hybrid techniques to improve the structural behaviour and shear resistance capacity of deep beams. Two beams were used as control with no strengthening, while the remaining ten beams were strengthened in different (with and without) steel shear reinforcement, orientation of NSM-FRP rods, hybrid techniques (combined of EBR-CFRP strip and NSM-CFRP rods). The beams were designed to fail in shear and to match with the requirements of ACI 318M-14 building code. Results showed that the hybrid technique caused an increase in the load carrying capacity for the deep beams up to 58.5 % when compared to the beams without strengthened control one.
Potential assessment of immersive visualization for better cost definition during semi-detailed engineering phase
Authors: Arif F , Farooqi R A , Bayraktar M E
Published: March 2020

Traditional method of defining design and cost scope of project between the client and consultant requires repetitive updates and visualization. However, lack of proper visualization persists during this phase i.e. semi detailed engineering. This results in longer cost blackout periods and weaker cost control leading to less accurate budget scope. Mostly drawings and (sometimes) scaled models are used in getting feedback from client. With the emergence in the visualization technology, it is possible to get immersed in a full-scale interactive virtual environment and experience everything like it is happening in real. This technology has a potential to present things in “interactive-immersive-physics” enabled environment as a way to assist in cost and design appraisals happening between client and consultant. This paper aims at reviewing potential of “Immersive visualization” and summarizing the factors that can be controlled using the same in construction projects to improve cost engineering process during semi-detailed engineering phase. The study will provide knowledge base for implementing virtual reality into construction project scope definition. Review, potential best practices alongside inputs from field professionals and experts will be utilized to achieve the objectives of this study.
Evaluation of CO2 sequestration efficiency by Pozzolime concrete
Authors: Alsaad A J , al-Attar T S , Alshathr B S
Published: March 2020

Reducing CO2 emissions from cement industry is vital. Portland cements manufacturing is responsible for 5 – 8 % of global greenhouse gases. Therefore, using alternative binders in concrete is necessary to reduce the environmental impact of cement. This work goals to investigate the efficiency of Pozzolime concrete in CO2 sequestration from the environment and then to convert it into calcium carbonate inside the concrete. The Pozzolime concrete was tested at the ages of 14, 28 and 56 days with two moist-curing ages; 14 and 28 days. The studied mixes were exposed to 15 and 25 % of CO2 concentration for a period of 24 hours. The efficiency was evaluated through compressive strength, carbonation depth, CO2-uptake and weight change. The results showed that higher concentration of CO2 for exposure of 24 hours caused a significantly higher carbonation depth. The maximum CO2 uptake was recorded at the age of 14 days for Pozzolime concrete, when exposed to 25% concentration of CO2.
Effects of palm fronds fibers on properties of high-volume fly ash concrete
Authors: Al-Shathr Basil S. , Eedan Osama A. , Hussain Ruaa M.
Published: March 2020

Portland cement concrete is considered as the most difficult product in environmental pollution, although it is the main construction material. One of the alternatives is high volume fly ash concrete which uses low cost binding material (waste material) as a high replacement to Portland cement. This type of concrete is brittle similar to traditional concrete. So, the aim of this research is to use organic fibres (palm fronds fibres), which is a waste material, in enhancing the tensile property of this concrete (that use 50 % and 60 % replacement of fly ash). The percentages of fibres used are 0.4, 0.8, 1.2, 1.6, and 2% by volume of concrete to find the optimum percentage of it. The effects of fibres were studied on dry density, compressive and tensile strength, and drying shrinkage upto 90 days age. Results indicate that the optimum percentage of palm fronds fibres that can be added to high volume fly ash concrete (with 50 or 60% replacement of cement by fly ash) is 1.2% by volume.
The effect of using different percentages of soil and fine aggregate on stabilized earth bricks
Authors: Abed Ziyad M.
Published: March 2020

In this research, the production of stabilized earth bricks with cement using different percentages of soil, and sand has been studied. Earth brick are used as a replacement of fired clay bricks and concrete bricks. To estimate the effect of these different percentages of component, four percentages with (40% sand, 50% soil, 10% cement), (30% sand, 60% soil, 10% cement), (10% sand, 80% soil, 10% cement) and (0% sand, 90% soil, 10% cement) were used. On the other hand, water curing was used for these mixtures. Modulus of rupture, compressive strength, bulk density and water absorption, for different ages (7, 14 and 28 days) have been tested. There was an improvement in properties of Compressive strength, modulus of rupture and decrease in bulk density.
Relationship between steel mass loss and accelerated corrosion regimes in reinforced concrete columns
Authors: Radhi Mushtaq Sadiq , Hassan Maan S. , Gorgis Iqbal N.
Published: March 2020

Present study aims to observe the consequence of varying the intensity of the accelerating impressed electrical current and situations of wetting-drying as hybrid accelerated corrosion regime on synthetically corroded concrete specimens, especially the loss of steel mass. Small-scaled reinforced concrete columns were fabricated and synthetically corroded by altered accelerating corrosion situations by applying an impressed current with intensity ranging between (50 and 500 μA/cm2). Moreover, the impressed current joined with two dissimilar durations of wetting-drying cycles for assessment. The steel mass losses during and at the end of the accelerated corrosion process were calculated, also, cracking configuration and damage shape were observed for accelerating corrosion. The outcomes designated that the hybrid method (impressed current joined with cycles of saline solution wetting and drying series) can be employed adequately to simulate the regular corrosion process in the reinforced concrete structure. The steel mass loss is mostly influenced by the intensities of the impressed accelerating current, while the crack appearance and the pattern of surface cracks, is influenced by wetting and drying cycles as well as the impressed accelerating current. Yet, increasing the current intensity produce a considerable growth in the cracking owing to the reinforcing steel corrosion in shorter stage.
Properties of self-compacting mortar containing nano blast furnace slag
Authors: Atiyah Alaa Ab , Salih Shakir A , Kadhim Ahmed S
Published: March 2020

In this research, an experimental study of the properties of self-compacting mortar with Nano blast furnace slag has been done. Nano blast furnace slag was prepared and used as an additive to the self-compacting mortar in (1, 2, 3, 4, 5) % by weights cementitious sustainable materials. Blast furnace slag was crushed and milled until achieving to Nano particle size, Nano particle size was provided and checked by Laser Particle Size Analysis, AFM, and FESEM. Self-compacting mortar was tested at 7, 28, and 90 days’ age. Fresh properties of self-compacting mortar were determined by using mini flow table test and mini v-funnel test. The experimental results of self-compacting mortar shown that the mechanical properties include compressive strength, flexural strength, and direct tensile strength were increased as Nano powder percentage increases. The physical properties such as total water absorption and porosity was decreased as a Nano powder percentage was increased. While the density of self-compacting mortar increased as Nano powder percentage increase. The microstructure homogeneity and Nano powder distributions of self-compacting mortar were explained by using FESEM.
Effect of incorporating hydrated lime on strength gain of high-volume fly ash lightweight concrete
Authors: Mohammed M E , Al-Shathr B S , al-Attar T S
Published: March 2020

High-volume fly ash concrete, HVFALC, may acquire popularity as durable, resource-efficient, and option of sustainability for different applications of concrete. The Pozzolanic reaction between fly ash, Ca(OH)2 and water is the cause of making high-volume fly ash concrete a promising sustainable material. The aim of this study is to enhance the rate of the Pozzolanic reaction by incorporating external source of hydrated lime in the mix by two approaches. The first is to replace 10% by weight of the cementitious materials with hydrated lime and second is to use a lime-saturated water, with a concentration of 3g/L, for mixing. Two high-volume fly ash concrete mixes, with 50 and 60 % replacement by weight of cement, were included in this study. The testing program included water absorption, dry density, compressive and splitting tensile strengths. The testing program was extended to the age of 120 days.

The present results showed that both approaches have caused an increase, ranging between 10 and 24 %, in absorption values and a slight reduction, less than 3 %, in dry density values. Both approaches have caused a significant gain in compressive and splitting tensile strengths. Replacing 10 % by weight of the cementitious materials with hydrated lime caused better enhancement in compressive and splitting tensile strengths for all curing ages than using lime-saturated water in mixing. The former approach was more effective for mix FA60 than for FA50 and the higher fly ash content in the FA60 mixes could be the reason.
Investigating set-controlling additives for Pozzolime mixtures
Authors: al-Attar T S , Al-Shathr B S , Hadi R S
Published: March 2020

Pozzolime, PL, is a promising sustainable building material, because of its low carbon footprint on environments as compared to Portland cement. Portland cement contributes to about 7% of the global CO2 emission. The Pozzolime is produced by mixing materials cause lower CO2 emission, the lime, and some industry by-products, silica fume or fly ash. Pozzolime paste exhibits longer setting time than the Portland cement mixtures. The initial setting time ranges from 20 to 21.5 hours and the final setting time ranges from 25–265 hours. Such characteristics limit the use of the new binder, PL. The aim of this research is to study the effect of many additives on the setting time of PL paste. The study includes the investigation of using plaster of Paris (CaSO4), natural gypsum (NG), cement kiln dust (CKD), and sodium bicarbonate (NaHCO3), as set-controllers. The results showed that the most effective set-controller was the sodium bicarbonate due to the composition of sodium hydroxide, which is considered as accelerator to the pozzolanic reaction.
Influence of using different percentages of waste materials on the strength properties of polymer concrete
Authors: Thari Ahmed I. , Salih Shakir A. , Hasan Shatha S.
Published: March 2020

Polymer concrete is a developed combined substance with greater characteristics in contrast with traditional concrete for example greater mechanical strength and chemical resistance. The aim of this paper is to investigate some properties of polymer concrete with and without waste glass as an aggregate. The waste glass was prepared and combined with different proportions of traditional sand. The mechanical properties (compressive strength, splitting tensile strength and flexural strength) were experimentally determined. The polymer concrete containing crushing waste glass was compared with polymer concrete containing normal fine aggregates. It was found that the waste glass could be used to produce polymer concrete and also is suitable for environment. This study concluded that 22% resin 78% fine aggregate of the total weight of mixture provides for the optimum distribution of fine aggregate, for that reason the best resin to fine aggregate ratio was chosen. The aggregate in polymer concrete was replaced with 5%, 10%, 15%, and 20% by weight of waste glass. It was also found that the compressive strength, flexural and tensile strengths of polymer concrete containing waste glass aggregate increases as the waste glass aggregate content increases.
Settlement assessment of gypseous sand after time-based soaking
Authors: Mahmood Mohammed Sh. , Akhtarpour Ali , Almahmodi Rusul , Husain Mustafa M.Abdal
Published: March 2020

This paper investigates the effect of the soaking process on gypseous sand soils. The recent research investigates the time-based soaking method on high gypsum contents (29%) of soil samples. The softening of gypsum materials upon wetting process leads to break the bonds of the soil particles and the settlement of structures will be occurred. The settlement value and rate are the basic problems for the geotechnical engineers. The samples of this investigation have been collected from the selected site in Al-Najaf city in Iraq, then these samples are remoulded to the density of 85% of the maximum dry density from Proctor test and moisture content of 4% in the cell of the computerized Oedometer device and under different stress levels (1.11, 2.23 and 4.47 kg/cm2). The soil specimen is soaked under three stress levels (1.11, 2.23, and 4.47 kg/cm2) separately. The results revealed that with increasing of soaking periods and stress level, there is increasing in collapse potential of such soils. The collapse potential was increased from <1% after half-hour soaking to about 8% after two-weeks of soaking.
Performance of piled raft foundations under the effect of dewatering nearby an open pit
Authors: Al-Qaisee G S , Ahmed M D , Ahmed B A
Published: March 2020

The dewatering arrangement is required in execution works and it needs more attention due to the additional vertical settlement produced on the adjacent pile foundations. Raft foundations are being increasingly utilized for construction in cases of subsoil conditions with a high water table. Also, soil displacements in adjacent un-braced deep open pit may be a reason for high damages to the close buildings and foundations systems. The aim of this study is to examine the behaviour of piled raft foundations considering different pile locations under the effect of line drain and stage drilling of nearby open foundation pit. The line drain was used as dewatering process through the soil in this study. The pile vertical settlement and lateral displacement at various depths of excavation of an open pit in addition to the effect of line drain were investigated. A numerical modelling by using the three dimensional finite element package PLAXIS 3D is presented to simulate the problem. The soil is presumed to consist of two layers of deposit, the first is a clayey layer assuming soft soil criterion and the second is a sandy layer conforming to Mohr-Coulomb failure criterion. It is found that there is an obvious effect of dewatering by line drain with the drilling process for corner and face piles of a piled foundation whereas less effect for the centre piles.
The morphology and elemental variation for contaminated clay soil using Energy Dispersive X-Ray Spectrometry
Authors: Saeed K A , Hashim S A
Published: March 2020

It is known that the stabilization of normal soils with chemical substances will gradually affect their properties like shape, size and soil particles arrangement. The current study concerns with artificially contaminated clayey soils immobilized by fly ash waste materials and quicklime (CaO). In this research, the time-dependent factor changes the morphology of stabilized – contaminated soil. Energy Dispersive X-ray Spectrometry is performed to further examine components on the clay particles’ surface. The results showed that with an increase in hardening time, morphology analyses by FESEM shows a transformation of soil fabric due to the effect of chemical treatment, and due to the production of cementitious pozzolanic compounds (CSH and CASH). However, with the presence of contamination, it can notice a transformation in the fabric of clay particles towards a more flaky nature at the early curing time due to precipitation of heavy metals as hydroxide or sulphates on the surface of particles. Regarding the EDAX analysis, the Al:Si ratio for cement - fly ash treated clayey soil decreases over time. This is attributed to the increased release of alumina from the mineral of clay structure. However, an increasing Ca:Si ratio is observed, especially after 100 days related to the formation of the portlandite compound from cement hydration over time. While, it is detected variation in these ratios with respect to contaminated soil with time.
Measuring pile shaft and tip capacities of a single pile embedded in saturated and unsaturated expansive clayey soil
Authors: Fadhil Shaimaa Hasan , Al-Omari Raid R. , Fattah Mohammed Y.
Published: March 2020

This research presents a series of compression load tests conducted on a single pile embedded in saturated and unsaturated expansive clayey soil. Soil water characteristics curve (SWCC) and initial soil suction (total and matric) are measured using the filter paper technique to study the influence of soil suction on the pile and tip capacities. Soil pressure gauge is used and embedded in the soil under the pile at a distance of 2D. The results showed that the ultimate pile capacity is increased when the initial degree of saturation decreases. In addition, the tip capacity is increased when the degree of saturation decreases. Then, the sharing ratios of the ultimate tip and shaft capacities to the ultimate pile capacity are calculated. The results have shown that the sharing ratio of the ultimate tip capacity to the ultimate pile capacity of a single pile is increased with the decrease in the degree of saturation while the ratio of the shaft capacity to the ultimate pile capacity is decreased.
Dynamic response of pile group model in sandy soil to lateral excitation
Authors: Fattah Mohammed Y. , Karim Hussein H. , Al-Recaby Makki K. M.
Published: March 2020

This study offers an understanding of cyclic response of piled foundations in dry and saturated sand with different relative densities. The results of dry soil reveal the mechanism of dynamic response of piles and soil subjected to dynamic horizontal shaking including the variation and distribution of acceleration, bending moment along the pile, and vertical soil pressure with time in different states of soil; and the vertical and horizontal displacements, end-bearing load, peak acceleration and the peak velocity of foundation with time. A series of 94 laboratory tests were conducted to measure the response of pile foundation when subjected to dynamic loads. Eight tests were conducted on single pile in dry soil at relative density (R.D.) 30% (loose) and 50% (medium); 66 tests on group of piles with different spacings and patterns in dry soil at relative density 30% and 50% were conducted, too. All tests were carried out under operating frequencies 0.5, 1 and 2 Hz under horizontal shaking. Twenty tests for single piles and pile group with different patterns and spacings at relative density 30% were performed in saturated sandy soil under frequencies 0.5 and 1 Hz under horizontal shaking. All tests were achieved with one embedment ratio (L/d=30). These tests were grouped in three different numbers of piles; 2 piles in row and line patterns, 3 piles and 4 piles; and three pile spacing ratios (s/d=3, 4 and 5).

The main conclusion is that the manufactured vibrating box can simulate accurately the earthquake motion induced on foundations and, especially pile groups. The values of soil pressure decrease with increasing frequency and relative density. The soil pressure shows slight change with increasing frequency, while no clear changes appeared between pile groups with different pile spacings. The pile spacing is an important indicator that affects the acceleration and time-frequency characteristics of the displacement at pile top. With the increasing of S/D, the internal forces are slightly reduced.
Comparison of results of pre-consolidation of soft soil using analytical and finite element software
Authors: Abdulnafaa Muhamd D , Al-dabbagh Ayman W , Mahmood Mohammed S
Published: March 2020

This paper targets to make a comparison between consolidation calculation for softy soil layer by two methods, by using usual analytical equations found in most soil mechanic books, and PLAXIS simulation. The second method used a finite elements method represented by PLAXIS program, with the same parameters that were used in the first method, and other default parameters necessary in PLAXIS calculations. The results show strong agreement between the two methods, especially in the Active and excess pore water pressure, total and effective stresses, and total settlement in soft clay soils. In another hand, a significant difference in the values of time of consolidation calculated by the two methods is observed. These differences appeared due to using many different equations to calculate the (cv) consolidation coefficient.
EVALUATION OF PULL-OUT CAPACITIES OF DIFFERENT PILE MODELS EMBEDDED IN UNSATURATED SANDY SOIL
Authors: Mahmood Mahmood Rashid , Kadhim Shaymaa T. , Sarhan Waleed K.
Published: March 2020

The rises of capillary water above the water table level in soil layers and make the soil partially saturated that is considered one of the most challenging problems that a geotechnical engineer may encounter. Partially saturated soils contain large percentages of voids between the structural soil particles that are filled by water instead of air. Physical and mechanical properties of partially saturated soils are different than the other soils (i.e. dry or saturated) such as effective stress, shear strength and seepage. In present work, pile models manufactured from steel with different geometry (H-pile, hallow square pile, and closed-ended pipe pile) of the same surface area embedded in partially saturated sand soils to investigate the uplift capacity. Poorly graded fine sand obtained from Baghdad city was used throughout this research. Partially saturated soils were obtained by lowering water level below soil surface to a depth of (i.e. 150 and 450 mm). Test results showed from the suction profiles of the soil that the matric suction increases with the lowering of water table. The ultimate uplift pile capacity was different in values based on the matric suction values. A comparison was made between the behaviors of steel pipe pile with other shapes of pile models used in terms of uplift capacities. The results showed that the degree of improvement in values of uplift capacity for first lowering of water level 150mm were (2.36, and 1.11) times than that of H-pile, and square piles, respectively. While the improvement in uplift capacity for a pipe pile when the water table level was lowering to a depth of 450mm, were greater than those of H-pile, and square steel piles by (2.22, and 1.10), respectively.
Developing International Roughness Index (IRI) Model from visible pavement distresses
Authors: Joni Hasan H , Hilal Miami M , Abed Muataz S
Published: March 2020

The pavement maintenance, rehabilitation, and design methodologies need an appropriate evaluation of the pavement functional condition. The roughness is generally recognized as a measure of the pavement functional capacity. The roughness of pavement is measured using IRI, which depends on the quantity of distresses existing on the pavement surface. This study focuses on developing a model to predict the roughness (IRI) from the flexible pavement distresses. Accordingly, 83 flexible pavement sections were selected in AL-Diwaniyah city roadways, Iraq. The length of the section is equal to 250 meters. Distress data were collected manually, in terms of amount and severity. The IRI data were collected from all sections using the Dynatest Road Surface Profiler (RSP) test system. Using SPSS software, a stepwise multiple linear regression has been used to develop the model between the IRI and visible pavement distresses depending on the data collected. The resulting equation was found among the IRI and percentages of polished aggregate, high and medium severity potholes, medium severity alligator cracking, medium severity patching, high severity raveling, and high severity corrugation. The results indicate that this model is strong enough for the prediction of the International Roughness Index.
Evaluation of moisture-induced damage of stone matrix asphalt mixture with polymer modified binder
Authors: Al Helo K H Ibrahim , Qasim Z I , Khalaf D A
Published: March 2020

Moisture – induced damage is one of the most common reasons for the premature deterioration of Hot Mix Asphalt (HMA) pavements. Over the years, extensive research has been carried out by scientists and engineers on this subject; however, pavements still succumb to early failure from infiltrating moisture. The purpose of this research is to study the moisture induced damage performance of Stone Matrix Asphalt (SMA) asphalt pavements using Styrene Butadiene Styrene (SBS) polymer modified asphalt binder. To achieve the objective of this research the Superpave gyratory compactor was used for preparing the asphaltic samples and determining the volumetric properties of mixtures. The physical properties of aggregate, bitumen and other mix materials were assessed and evaluated with the laboratory tests. The mixtures were prepared using penetration Graded (40-50) bitumen and a chemical named Polypropylene Fiber was used as a stabilizing additive. Volumetric properties, Marshall Stability, behaviour to moisture action etc. were determined in laboratory. From the results it is seen that addition of SBS to the asphalt binder has significantly improved the cohesion as well as adhesion properties of the asphalt binder, and hence the stripping performance. Therefore, it can be concluded that the SBS is suitable to be used as a modifier in order to enhance the properties of the asphalt binder and thus improving the performance of asphalt in and SMA mixes.
Evaluations of traffic flow on Al-Yarmouk Overpass Bridge
Authors: Ziboon Abdul-Razak T. , Qasim Zaynab I. , Faraj Almas
Published: March 2020

Traffic volume has been increasing rapidly throughout the country, people have a hard time because of the traffic problems especially on the peak hours causing traffic congestion which is the biggest problem in Baghdad city, one of the solutions for congestion is to build an overpasses bridge at intersections in order to minimize these kinds of problems, the research maintains to evaluate the overpass bridge with the help of GIS, the various advantage of GIS makes it an attractive option to be used to face the emerging traffic problems. The main objective of this research is analyzing the existing traffic situation on Al-Yarmouk Overpass Bridge and estimating the level of service via v/c ratios were level of service is one of the constant functions of traffic to either maintain a stable traffic flow or to identify and cure for traffic congestion by gathering information concerning the transportation system in the study area by using field information count, camera for estimating traffic volume, speed Gun device for measuring vehicle speed. The result showed that the overpass bridge operates with the level of service (LOS F), at which the vehicle relative to the road capacity (v/c) is (1.48) as illustrated in analysis map on the basis of analyses of the existing traffics situation of the bridge. Some improvements are suggested to improve the level of service, and optimization suggestion, in addition to geometric improvement, is suggested in this study.
Design of an Expert System for Airport Rubber Removal
Authors: Abduljabbar Ahmed S. , Salman Nawal Dawood , Jaleel Zeena Tariq
Published: March 2020

The most important parameter for airport operator is safety. Minimizing any possible risks for passengers, crew, and equipment is the main objective of applying safety management systems at airports. The rubber deposits that accumulate on the runway surface due to aircraft operations is one of the most critical factors that directly effects on the skid resistance value of the airport runway.

Four common techniques are applied throughout the world for mitigating this rubber strip water blasting, chemical, shot blasting, and mechanical. Every technique has its pros and cons in terms of cost, efficiency, environmental effect, and damage to pavement surface. The current design involves developing an expert system that takes into account the parameters that may support choosing the optimal method for rubber removal in certain situations. These parameters include airport classification, cost involvement, accessibility, pavement damage concerns, environment damage or side effects, and any additional factors such as noise.

The system is developed using webpage-based Expert System builder ES-Builder. Simple user interface, windows based, easy to build the decision tree are the major concerns for choosing this program to build the proposed expert system. The expert system follows a deduction process, until the expert system makes the final conclusion according to user selected answers. The proposed expert system works very well when selecting appropriate answers taking into consideration specific characteristics for each airport category. Faulty conclusions could be given if the user does not use the appropriate parameters related to the airport category. There is no optimum solution, every airport situation is different, and the solution or the recommended method varies from one airport to another.
Land use of Al-Ramadi City and its Impact on Sustainable Transport Strategies Using (AHP)
Authors: Mahmood Thaer Sh , Ibraheem Arwa H
Published: March 2020

Ramadi, the capital of Anbar province, has long suffered from a series of urban problems, mainly the problem of transport and traffic in the city. Sustainable development and climate change are high on the agenda for most cities around the world today. Urban transport is at the heart of these changes. For the purpose of proposing and implementing sustainable transport strategies in the city, this research presents a study to answer the most important question of how to prioritize strategies resulting from the impact of land use on sustainable transport standards. It is of paramount importance to give the decision-makers, administrative and technical staff in the city enough room to make the appropriate decision spatially, temporally and artistically using a modern method to apply descriptive and quantitative analysis together, which is the hierarchical analysis method (AHP). The research has encountered a number of difficulties, the most important of which is the scarcity of the field data, especially the road and transport data in the city, which led researchers to rely personally on the analysis and collection of data related to research and based on the opinions of experts and specialists in the field of transport planning, the analysis found that the strategy of integration of land use with the transport network, is of paramount importance, followed by the strategy of avoiding unnecessary trips and then a number of strategies according to priority and importance in the service of the city.
Assessment of the mechanical properties of concrete pavement containing crumb rubber of tires
Authors: Al-Khuzaie Muhaned G. , Al-Humeidawi Basim H. , Al-Sa’idi Ra’id F.
Published: March 2020

The disposal of waste scrap tires is one of the most important challenges and a massive burden facing the developed countries. One of the most important method to disposal it, is using the Crump Rubber (CR) of tires in roads and structural projects. The current research focused on assessing the performance of concrete pavement contained CR. The mechanical properties of concrete were evaluated after adding 5 percentages of CR particles as 2%, 4 %, 6 %, 8% and 10 % of total weight of aggregate. The work methodology involved investigation the effect of using different methods of treatment of CR compared with untreated CR. Also, it investigated the effect of CR particles’ sizes on the mechanical properties of rubberized concrete pavement. The results of study showed that the chemically treated CR can produce rubberized concrete pavement with properties closed to that of reference mix. The replacement with 2% and 4% CR gave adequate properties of pavement to be used in highway construction, while the 6% is closed to acceptable limit. The coarser particles showed better performance in terms of mechanical properties compared with the smaller particles (as replacement from sand). Chemically treatment by NaOH for CR only caused reduction in compressive strength of concrete by 7.6%, 15% and 28% while water soaking method produce more reduction in compressive strength reached up to 52.5%, 55.1% and 65.8% for the percentages of 2%, 4% and 6% CR respectively.
Evaluating the Negative Impact of Traffic Congestion on Air Pollution at Signalized Intersection
Authors: Alobaidi Maan k , Badri Rawand M , Salman Mohammed M
Published: March 2020

Traffic Congestion is considered as one of the largest contributors to the problem of air pollution at present. A major part of this pollution is due to emissions from vehicles. Intersections are considered as critical elements of road regarding the high level of air pollution which is due to the slow down and stop operations. Thus, the combustion of fuel is increased negatively as intersection compared with other types of road elements. The key focus of this paper is to estimate the negative impact of traffic congestion by calculating the quantities of gases emitted during the traffic congestion at the signaled intersection in Baghdad city. The traffic flow data was obtained by video recording of the study area. From these videos, data was analyzed by using Signalized and Un-signalized Intersection Design and Research Aid (SIDRA 8.0.) software. The selected emissions of HC, CO, NOX, and CO2 in (kg/hr) are based on delay and LOS computation at the signalized intersection. The results of this study will provide suggestions to the transportation and public health officials to reduce the risk of air pollutant by trying different approaches such as eco-routing and eco-signal timing.