Key Engineering Materials Vol. 870

Abstract: In the present work, the properties of Polyethylene Waste cement mortar containing Polyethylene Waste treated by a reactive material are tested and compared with normal Polyethylene Waste and normal cement mortar. The Polyethylene, which is cured by a different reactive material such as: (cement, a fly ash and silica fume) is used as fine as aggregate a volumetric fractional replacing of the sand in a cement mortar. The percent of replacement was 10% by volume, density, compressive strength, modulus of rupture, and absorption are tested for all mixes at variable ages. The current results display that the cure of Polyethylene by cement were significantly improves the characteristics of Polyethylene cement mortar. Moreover, the results show that all treatment improved properties of cement mortar as a compared with Polyethylene without treatment.

Abstract: Box culverts are the monolithic unit build to pass across railway lines, roadways, etc. earthworks are made to balance the discharge water on both sides. Box takes different types of loads created by a cushion, traffic, water, soil, etc. This paper deals with the optimum design of box culvert by using Newton's-Raphson Method and AppDesigner in MATLAB Software R2017a and studies the design parameters such as the influence of depth of earth fill at the top slab of the culvert, earth pressure, factor Dead Load, Live load, effective width, etc. In this paper, the study of the box-culvert with normal and minimum cushion analyzed for different classes of loadings and conclusions made on the basis of Newton's-Raphson Method normal and minimum cushion and normal cushioning cases.

Abstract: This research studied the effect of eggshell powder as a partial replacement of cement on fresh and hardened properties of concrete. The cement was partially replaced with eggshell powder at these percentage 0%, 2.5 %, 5 %, 7.5% and 10%, (by weight of cement). The resulting concrete was compared for impact resistance, energy absorption, load-slip characteristics and ultimate bond strength. setting time (initial and final), slump, density and compressive strength also have been found. The obtaining results indicated the advantage of incorporation of eggshell powder in concrete. The concrete unit weight has not obviously affected by eggshell powder content. The 2.5% eggshell powder give the best results compared to reference mix.

Abstract: This work focuses on investigating the behavior of micro and nanoFe₂O₃ in concrete through the study of microscopy, compressive strength and flexural strength. Seven mixes of concrete are prepared. Three of which include micro Fe₂O₃ comprising 1%, 3% and 5% as partial substitutions of cement weight and the other three mixes containing 1%, 3% and 5% nanoFe₂O₃ as a partial substitutions of cement weight, as well as the reference mix. SEM study exhibits that the microstructure of sample produced with micro Fe₂O₃ show more uniformity and dense compared with reference sample. However, existence of micro cracks in the microstructure in mixes with micro Fe₂O₃ is clear especially with increasing micro Fe₂O₃ content to 3% and 5%. In mixes with nanoFe₂O₃, the new shapes of needle like crystals and flower like crystals can be distinguished. The presence of these types of crystals in thrives amount approve that nanoFe₂O₃ producing new phases of gel. Hence, the microstructure of samples is condensed, and with the increasing of nanoFe₂O₃ content the microstructure is completely compacted. The results of compressive strength and flexural strength showed that the mechanical properties are related to microstructure properties. When micro Fe₂O₃ is used, the mechanical properties drop obviously. While, the mechanical properties are improved in mixes containing nanoparticles in comparison with the control mix.

Abstract: Nowadays, applying new materials is widely used in concrete construction to study their effects in enhancing the properties and the durability of concrete. This research includes studying the using of manufactured aggregate, which is so-called '' Anti-slip sand '' in specific proportions to know its influence on strength properties of normal strength hardened concrete which involves compressive strength, flexural strength, tensile splitting strength, and density. Anti-slip sand at different rates of (25%, 50%, 75%, and 100%) replaces the natural sand in the concrete mixture to investigate its effect on the properties of concrete. The study shows that the best results of concrete properties are found when replaced the natural sand by 100% of anti-slip sand. Compressive, flexural and tensile strengths of concrete are increased with increment ratios of (44%, 40%, and 20%) respectively compared with other concrete mixture contains only natural sand. In addition, the study shows that the density of hardened concrete is decreased from 2420 kg/m³ in concrete with 100% natural sand to 2360 kg/m³ with a decrement ratio of 2.5% in concrete with 100% anti-slip sand.

Abstract: A total of seven simply supported composite specimens are tested under concentrated load at the mid-span of the beam to investigate the strength of specimens to resist the applied load if web buckling take place. A novel technique of using a corrugated CFRP struts to strengthen the web of the steel girder is presented in this study. This technique provides two layers of CFRP laminate which are from biaxial fabrics to provide a knitted material that can undergo the complex state of stress in the web. The studied specimens are divided into two groups in addition to the control specimen having the same length. There are three specimens in each group, these specimens have different castellation ratios of (33.3%, 43.3% and 54.3%), the first group is identical to the second one except that the second group was strengthened with the proposed CFRP corrugated struts while the first one kept unstrengthen as a reference. Composite beams have a vertical stiffener at the action area above the supports. The reference group showed decrease in deflection of (11.11, 20 and 26.67) % for (33.3, 43.3 and 54.3) castellation ratio while strengthened girders record (13.75, 6.11 and 13.93) % for the same opening depths, compared to the control specimen. In addition, CFRP struts decrease the web buckling from (1.6, 2.9 and 83.33) to (0.8, 0.4 and 0.3) mm for beams with castellation ratio of (33.3, 43.3 and 54.3) respectively.

Abstract: This study was carried out to determine the possibility of improving the properties of the sand from Kasser Mohaiwir area in Al-Anbar Governorate to obtain sand specifications conforming to the standard sand specification (not exceeding 0.25% loss in acid). This study showed the possibility of obtaining standard sand with loss in hydrochloric acid up to 0.175 and recovery rate not exceeding 80% using mechanical methods without resorting to the use of acid methods currently in production.

Abstract: 3D printing innovation, as a quick prototyping, utilize plastic or metal as the crude material to print the genuine parts layer by layer. In this way, it is likewise called added substance producing procedure. Contrasted and conventional assembling innovation, 3D printing innovation has evident points of interest in assembling items with complex shapes and structures. Fused deposition modeling (FDM) is one of the most broadly utilized 3D printing advances. Fibers of thermoplastic materials, for example, polylactic acid is for the most part utilized as crude materials. The present examination will concentrate on the effect of the infill density, percent on the flexural strength of polylactic acid. Bending test was performed on different infill density, percent of specimens. According to ASTM D638.14 standards, samples for testing are made in different infill density, percent (20, 30, 40, 50 and 60 %) by using a polylactic acid in 3D machine printing and their tensile tested and the parameters include different fill density, layer high of 0.1 mm , 0.2mm and 0.3 have an effect on the mechanical characterized while the time of printing the sample would be increased with increasing of fill density%. The tensile strength of polylactic acid samples was found at different fill density and a layer thickness. According to test measuring results that the tensile strength, maximum 47.1,47.4, and 48 MPa at 30%,40%,and 50% fill density respectively and 0.1mm height layer and the tensile strength minimum at 60% and 70 % fill density and 0.1 mm height layer thickness. The higher strength results as higher layer thickness 0.3 mm as compared with 0.1 and 0.2 at 30%fill density.

Abstract: Ethyl acetate as acyl accepter have been used for sewage sludge biodiesel production in micro packed bed reactor. Lipase acrylic resin enzyme activity was investigated in the interesterification reaction of converting the sewage sludge into a biodiesel product. The main parameters affecting the process was adjusted via the design of Box-Behnken and approach of response surface then the optimum conditions were as follow (reaction time=15 h, ethyl acetate/oil ratio=24:1, temperature=40 °C and enzyme quantity=18 wt%) providing 95.78 % biodiesel yield. The lipase acrylic resin was examined under the optimum conditions for the reusability. the flow effect and the heating process of the micro packed bed reactor was investigated. The product biodiesel physicochemical properties were evaluated according to the ASTM D-6751-2 and found acceptable comparable to the mineral diesel properties.