Abstract

The research aims to examine the effect of Hawkins' strategy on students in the fourth grade of primary school in the General Directorate of Education in Baghdad / Karkh 3 for the academic year (2020-2021). The research was limited to the topics of the Arabic language grammar book for the fourth grade of primary school. The researcher developed the research hypothesis, which is: that there is no statistically significant difference at the significance level (0.05) between the average scores of the experimental group students who study using the Hawkins strategy and the average scores of the control group students who study in the traditional method in the achievement test. The researcher set a number of

This study focuses on the behavior of simply supported perforated prestressed concrete rafters (PPCRs) under single midspan monotonic static loading. The experimental program consisted of testing seven specimens; one solid (control) rafter, and six perforated with quadrilateral openings. The main investigated variables are the number and height of the openings. The test findings indicate that, in comparison to the solid rafter, the presence of quadrilateral openings in the PPCRs led to reducing the load capacity by (4.3-36%) and increase the midspan deflection at ultimate by (14.8-33%). Also, increasing the number of concrete posts between openings resulted in increasing the failure load and decreasing the deflection at all stages o

The structural behavior of Segmental Precast Post-tensioned Reinforced Concrete (SPPRC) beams largely depends on the behavior of the joints that connect between the segments. In this research, series of static tests were carried out to investigate the behavior of full-scale SPPRC beams with different types of epoxy-glued joint configurations; multi-key joint, single key, and plain key joint. The reference specimen was monolithically casted beam and the other specimens were segmental beams with five segments for each one. The general theme from the experimental results reflects an approximate similarity in the behavior of the four beams with slight differences. Due to the high tensile strength of the used epoxy in comparison to concr

Corrosion inhibiting admixtures are unique among other methods to protect reinforced concrete from corrosion damage. In this study, the effect of furfural on the fresh and hardened properties of concrete mixes of 35 and 45 MPa compressive strengths as well as the corrosion inhibition of furfural was evaluated. Furfural was added at different dosages (1, 2 and 3% by weight of cement) with and without superplasticizer (HRWR). Different electrochemical measurements were performed (Half-cell potential, Tafel plot and linear polarization resistance). Electrochemical measurements confirmed that furfural dramatically reduces the rate of corrosion; the inhibition efficiencies were 62.7 and 63.8 % due to 3% furfural addition to 35 and 45MPa-concr

Implementation of Warm Mix Asphalt concrete (WMA) is getting global acceptance due to the restrictions for protecting the environment and the requirements to reduce fuel consumption. In this investigation, two WMA mixtures have been prepared in the laboratory using medium curing cutback (MC-30) and Cationic emulsion asphalt. Hot Mix Asphalt (HMA) was also prepared for comparison. The cylinder specimens (63.5mm) in height and (101.6mm) in diameter were constructed from the mixtures and subjected to indirect tensile strength test to determine the Tensile Strength Ratio (TSR). The cylinder specimens of (101.6mm) in height and (101.6mm) in diameter were also constructed from those mixtures and subjected to static compressive

Fatigue cracking is the most common distress in road pavement. It is mainly due to the increase in the number of load repetition of vehicles, particularly those with high axle loads, and to the environmental conditions. In this study, four-point bending beam fatigue testing has been used for control and modified mixture under various micro strain levels of (250 μƐ, 400 μƐ, and 750 μƐ) and 5HZ. The main objective of the study is to provide a comparative evaluation of pavement resistance to the phenomenon of fatigue cracking between modified asphalt concrete and conventional asphalt concrete mixes (under the influence of three percentage of Silica fumes 1%, 2%, 3% by the weight of asphalt content), and (chan

In this study, two types of mixes were adopted by using two grading of coarse aggregate. The practical side of this study was to produce no-fine aggregate concrete by using crushed clay brick aggregates. The durability of the produced concrete and internal sulfate attack was studied.      For durability assessment, it is found that the no-fine concrete made with crushed brick aggregate lost about (15-25) % of its compressive strength after being subjected to 60 cycles of wetting and drying with age 120 days. The curing condition showed that the water curing improved the compressive strength with a rate higher than that when sealed or air dry curing were used. The crushed brick no-fine concrete de

The - mixing ratios of -transitions from levels in populated in the reactions are calculated in present work using - ratio, constant statisticalTensor and least squares fitting methods The results obtained are in general, in good agreement or consistent, within the associated uncertainties, with these reported in Ref.[9],the discrepancies that occurs are due to inaccuracy existing in the experimental data The results obtained in the present work confirm the –method for mixed transitions better than that for pure transition because this method depends only on the experimental data where the second method depends on the pure or those considered to be pure -transitions, the same results occur in – method