Roller compacted concrete (RCC) is a concrete compacted by roller compaction. The concrete mixture in its unhardened state must support a roller while being compacted. The aim of this research work was to investigate the behavior and properties of roller compacted concrete when constructed in the laboratory using roller compactor manufactured in local market to simulate the field conditions. The roller compaction was conducts in three stages; each stage has different loading and number of passes of the roller. For the first stage, a load of (24) kg and (5) passes in each direction had been employed. For the second stage, a load of (104) kg and (10) passes in each direction were conducted. Finally, at the third stage, a load of (183) kg and (15) passes were adopted. Such procedure was in accordance to previous work conducted by the author. The effects of the type of coarse aggregate (crushed and rounded), fine aggregate (river and natural) and cement type (OPC and SRPC) on the mechanical properties of RCC were investigated. The effect of compaction method on compressive strength and indirect tensile strength was also discussed. A total of (26) roller compacted concrete slab samples of (380×380×100 mm) were prepared in the laboratory, Then, the slab specimens are taken out of the molds and immersed in the curing tank for (28) days. Core and Beam specimens were obtained from the slab samples for the determination of mechanical properties. Such properties include compressive, indirect tensile, flexural strengths using one point loading. It was concluded that the compressive strength of RCC using crushed aggregate is higher than that when using rounded aggregate in a range of (15-66) % for core specimens, while the compressive strength of RCC when using river sand is higher than that when using natural sand in a range of (9-26)% for core specimens. When river sand is implemented, RCC samples show higher indirect tensile strength than those with natural sand, such variation is within (7-8) %
The city has normal natural state, and the man has a usual movement, change and search for the new .Also, the city has a usual change and transform in its time, place and quality (sizes)structures. The city has a solid memory diving into the past and the future and reflects The real present, and this memory has a timing layers change into real materialistic place making the city has accumulated overlapping circles which is hard to break u , and it broadcasts the lockup timing density ,in which there is no visual record precisely, it is just like((the social record)) that evaluates the un visual relationships between the components and parts of the city (community and form) in a visual quiet exhibition and transform change inside.
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This study aims to identify the extent to which the criteria of the American Council for Teaching Foreign Languages (ACTFL) are included in the English language books for the fifth and sixth graders. To achieve the objective of the study, a content analysis card was prepared, where the classification of language proficiencies was divided into five main levels (beginner, intermediate, advanced, superior, and distinguished) of the four language skills (listening, speaking, reading, and writing), The content analysis card consisted of (89) indicators distributed at the four levels of language skills as follows: Listening (17), speaking (33), reading (15), and writing (26). The study sample consisted of Engl
... Show Morethis research is to identify the level of information awareness of the chemistry students in their fourth year studying at Ibn Al-Haytham Education College of pure sciences at the University of Baghdad. The research sample consisted of (107) male and female students out of the total number of (153) students studying during the (2017-2018) academic year, The sample therefore represents 71% of the total students. The research methodology used consisted of two parts. The first part is concerned with measuring information awareness using a multiple choice type of test related to (40) issues. The students were required to select the between (5) alternative answers for each issue. The objectives of the test and the issues used are to measure the
... Show MoreThe exchange rate is of great importance at the global and local levels alike, as this importance increases with the increasing rates of development of economic relations between countries of the world due to openness and integration into the global economy, expressed by the expansion of the volume of trade and financial relations between countries. The Central Bank of Iraq has set the need to stabilize this price as a goal to reduce inflation rates and reduce them to the internationally accepted rates by using the foreign currency sale window to achieve a balance between the forces of supply and demand for foreign currency and to preserve the value of the Iraqi dinar. The research concluded that the central bank was It has a maj
... Show MoreThis work presents a novel technique for the detection of oil aging in electrical transformers using a single mode optical fiber sensor based on surface plasmon resonance (SPR). The aging of insulating oil is a critical issue in the maintenance and performance of electrical transformers, as it can lead to reduce insulation properties, increase risk of electrical breakdown, and decrease operational lifespan. Many parameters are calculated in this study in order to examine the efficiency of this sensor like sensitivity (S), signal to noise ratio (SNR), resolution (refractive index unit) and figure of merit (FOM) and the values are for figure of merit is 11.05, the signal to noise ratio is 20.3, the sensitivity is 6.63, and the resolution is 3
... Show MorePolyvinyl chloride (PVC) finds use in various industries due to its versatility but is not thermostable, serving as a barrier to causing degradation and release of hydrochloric acid (HCl) under heat stress conditions. Lead and organotin compounds have traditionally been used for stabilizer purpose to discourage such degradation but pose serious ecological as well as health risks. As a counter measure, bio-based stabilizers from plant oils have become popular as a green and sustainable alternative. This review looks back at recent developments in plant oil-based stabilizers for PVC, focusing on the mechanisms of stabilization, sustainability, and cost-effectiveness. We review plant oils such as tung oil, castor oil, and soybean oil,
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The research aims to shed light on the Corona pandemic and its repercussions on the global economy in general, and on the activities of Iraqi economic units in particular. It also aims to show the impact of the auditor’s reporting on the effects of the Corona pandemic on economic units and its reflection on the quality of his reporting. To achieve the objectives of the research, the researcher prepared a questionnaire according to the five-point Likert scale and took into account in its preparation compatibility with the characteristics of the study community, and that the target community for this questionnaire are the economic units listed in the Iraq Stock Exchange that have complet
... Show MorePolyacrylamide Solutions of different concentrations (0.2, 0.4, 0.6, 0.8, 1.0 %) of Ag nanoparticles and ZnO nanoparticles were prepared, the viscosities and surface tension were measured for all solutions, where measurements indicated an increase in these properties with increased concentration, where the relative viscosity of polyacrylamide/zinc nanoparticles increased from 1.275 to 2.243, and the relative viscosity of polyacrylamide/silver nanoparticles increased from 1.178 to 1.934. Viscosity is significant parameters during electrospinning process. While the surface tension of the polyacrylamide/zinc nanoparticles has changed from 0.0343 Nm-1 to .0.0.0 Nm-1 and changed from .0.000Nm-1 to.0.0.0 Nm-1. Also the constants KH and KK were
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