Civil Engineering
Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/675
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Item ENHANCING CONCRETE MECHANICAL PROPERTY USING LIQUID PHASE SHEAR EXFOLIATED GRAPHENE NANO PLATE(Hawassa University, 2019-10-19) KIBROM GETACHEW BELAYPresent investigation deals with the methods adopted to produce and introduce Liquid phase shear exfoliated multi-layered Graphene. Recently, the development of an ideal Nano-material called graphene in modern science create an opportunity to develop better performing Nano-engineered materials. Thus, the compression and splitting tensile test result for 50% and 100% replacement of mixing water by produced Graphene solution, related modulus of elasticity is calculated based on compression result obtained. Such way that 28 days’ compression capacity show 33.4% and 16.5% improvement for 50% and 100% replacement of mixing water with Graphene solution. Moreover, the 28 days splitting tensile strength test result show 43% and 10% improvement for 50% and 100% replacement of mixing water with Graphene solution. The chemical crystalline matrix crushed pieces of test samples of Graphene solution made concrete were confirmed by using scanning electron microscope (SEM). Here we report that a significant enhancement of mechanical properties of the Graphene solution produced concrete than the conventional concrete.Item EXPERMENTAL INVESTIGATION ON CONCRETE BY PARTIALLY REPLACING SAND WITH CRUSHED STONE DUST(Hawassa University, 2021-10-22) GUNSAMO GUSSA DIMATOConcrete is the most widely used construction material in urban areas of Ethiopia. Out of different constituent materials of concrete, fine aggregate is one of the key materials and river sand is the most common form of fine aggregate used in Ethiopia. However, with increased dwelling demand and construction activities in Ethiopia, the demand for river sand has increased which is leading to large scale depletion of river bed and increasing cost of sand to be afforded by common man. This has compelled the researchers to find alternative sustainable materials in place of river sand which can be easily used as fine aggregate in concrete. Various industrial wastes and agrowastes have been tried as an alternative to river sand and the results are promising. This research work aims at examining the viability of using crushed stone dust as a fine aggregate in concrete. So, in this research work an attempt has been made to experimentally investigate the mechanical and durability properties of concrete using crushed stone dust as fine aggregate. Different concrete mix samples were prepared by using query dusts as fine aggregate in different proportions from 30% to 70% by volume and the strength and durability properties were compared with that of controlled concrete at several curing period. The experimental result revealed that, adding crushed stone dust as a partial replacement of sand in concrete has positive influence on the strength and durability properties of concrete.Item STRUCTURAL PERFORMANCE OF ME-PET FIBER REINFORCED CONCRETE(Hawassa University, 2021-10-18) ADDIS ALEMAYEHU KIYAMOThe aim of this paper is to investigate the effectiveness of manufacture embossed polyethylene terephthalate (PET) fibers in enhancing strength, deformation and durability of C25 concrete. This was achieved by both (i) adding to the concrete mix these above said recycled polyethylene fibers and (ii) maintaining the C25 plain concrete without the fibers for control purposes. Fresh properties of concre was prepared with the addition of various percentages of the PET fiber at 0, 0.5, 1.0, 1.5 and 2% of the concrete by volumetric fractions. Compressive strength tests were performed on forty-two (42) 150mm concrete cubes and splitting tensile strength tests were performed on twelve (12) (150*300) mm cylinder with the addition of various percentages of the PET fiber at 0, 0.5, 1.0, 1.5 and 2% of the concrete by volumetric fractions. Flexural strength tests were also performed on fifteen (15) 150mm×150mm×600mm concrete beams with the addition of PET fibers at 0, 0.5, 1.0, 1.5, and 2.0% of concrete by volume. The other parameter considered was deflection behavior the concrete beams with the mentioned amounts of fiber addition. To study the durability properties, 90 days’ compressive strength test, water absorption test, and effect of elevated temperature on residual compressive strength test were conducted on C25 concrete. The test results showed a significant increase in compressive and splitting tensile strength up to 21% and 27% at 1.0% of PET fiber respectively. Flexural strength of the concrete beams on the other hand increased by 17.5% for 1.0% fiber concrete compared to the control. The results of deflection performance of concrete beam with PET fibers also produced larger deflections at near maximum load.