Recent developments in mechanical applications have led to the development of metal matrix composites, which represent the future of composite structures. Al7010 aluminium alloy matrix with nano-ZrO2 and graphene particle reinforced composite is created in this experiment. By adopting the stir casting procedure in two different casting, 2 percent reinforcement of zirconium dioxide and 1 percent of graphene is included in the composite materials. The composite’s metallurgical and mechanical characteristics are studied. The SEM image demonstrates uniform dispersion of the particles in the alloy matrix. The manufactured material’s ability to gather particulate matter is clearly found in SEM and EDS. The addition of zirconia particles works together to prevent the alloy matrix from dislocating, which increases the base material’s hardness as well as its tensile resistance. Similar results are also found in graphene-casting material. Results from tensile tests reveal that adding nano-zirconium dioxide particle (ZrO2) and graphene boosts the material’s tensile and hardness strength. In terms of the ultimate tensile strength (UTS), the Al7010/2% ZrO2 composite had a 6% increase and Al7010/1% graphene had a 5.5% increase above the Al7010 alloy. Compared to Al7010 alloy, the microhardness of Al7010/ZrO2 is 17.64% greater and Al7010/1% graphene is 14% greater.

In the construction industry, construction material is one of the major cost components and it is 50% to 70% of the total construction cost. However, the industry generates 30%-65% of wastage for landfill. Effective use of construction material is profitable in the industry as well as in the economy of any country. However, material wastage management in construction are rarely studied by Ethiopian context. Hence, this research is aimed to investigate cause of construction material wastage and rank highly wasted construction material wastage on public building projects in western Oromia. The Study uses both primary and secondary data by structured questionnaires and case study (interviews and site visits). The research has covered a population of General and Building contractors from level one to three and their supervisor's that are employed in western Oromia on public buildings. The purposive sampling techniques were used to collect the data and Analyzed and presented by mean score by using statistical package for social science (SPSS) and excel worksheets. The result of the study analyses, mostly causes of construction materials are; Changes made to the design while construction is in progress, Lack of attention paid to dimensional coordination of products, Damage during transportation, Improper planning for required quantities, Designer's inexperience in method and sequence of construction. In addition, causes of construction material wastages are presented under seven attributes causes. As well as wastage of material on eight key construction, material are ranked as concrete, wooden formwork, block, and steel are most wasted by asking respondents based on their experience in the construction industry. Generally, wastage of material is highly occurred in every activity i.e. during design, construction and during the production of the material.

Flexible pavement roads in Ethiopia often deteriorate in different ways, because of the harsh climatic conditions, lack of proper design and quality control, sudden increasing of traffic due to the construction of different industries, high loads and inadequate assessment for identifying causes of deteriorate before carrying out Maintenance and Rehabilitation. A possible remedial measures had been organized for every observed failure or deterioration to obtain normal pavement condition of the study area. An investigation was made by using laboratory and field test to determine the adequacy of the underlain material to serve as a subgrade, sub base course and base course for road construction based on project specifications and Ethiopian Road Authority (ERA) Specification. The investigation covered field tests to determine the in-situ condition of the road materials while laboratory tests on representative samples were extracted from site to determine the engineering properties of soil materials and to compare test results with the existing conditions of pavement layers. From the field tests and laboratory tests carried out, it is observed that the causes of flexible pavement deterioration of this road section are mainly due to the inadequacy of existing thickness of the base layer for the current traffic loading, overloading, engineering properties of the pavement layers material, poor method of construction, poor design quality and lack of side drainage. To reduce these causes, use boulder rocks at subbase course, reconstruction the base and providing proper drainage for the deteriorated sections must be required to reduce more damage of the flexible pavement the road section. Raveling, pumping, potholes, edge cracking and rutting are the most dominant type of deteriorations constituting more than 27% of the deterioration densities along Bako-Gedo road section.

The problem of environmental pollution and health hazards due to inappropriate solid waste disposal is critical in developing countries like Ethiopia, Nekemte town is one of the town in Ethiopia facing from environmental pollution due to lack of appropriate dumping site which leads pollution of surface and ground water and environment in and around dumping area. Therefore, the main objective of this study is selection of suitable site for disposal of solid waste using Geographic Information System (GIS) tools. Selection of the most suitable landfill site was determined through the integration of geographic information system (GIS) tools, multi criteria decision analysis and remote sensing techniques. To select suitable landfill site several parameters were considered such as slope, built up area, , road, surface water, land use/land cover, geology and soil. After analysis of suitability of solid waste disposal site using GIS tools and weighted analysis methods selected 36 areas for medium solid waste Bins. Suitability map was prepared by overlay analyses on GIS based Weighted Linear Combination analysis to select the suitable solid waste disposal sites and assigned as the value given 1; unsuitable, 2; less suitable, 3; moderately suitable ; 4; Suitable and 4; highly suitable were determined. Using this method selected 2 highly suitable areas for land fill and inclination area

Road constructing in Ethiopia is increasingly in demand to meet its medium and long term development programs. Most internal road of Oromia cities/town are cobblestone and gravel. Some portions along the alignment proposed and existing roads traversed low resistance of the subgrade that affect the stability of upper layers of cobblestones.  Structural failures are observed on cobblestones roads, would it be constructed by good quality or low quality of materials. Nekemte Cobblestones Projects have been started in 2014 widely which were failed in most area today as we observed that needs to be addressed and a corresponding remedial measures must be drawn. A possible remedial measures had been organized for every observed  failure  or  destroyed  to  obtain  normal  road  condition  of  the study  area. An assessment was made by using observation, interviews, laboratory and field test to determine the adequacy of the cobblestones, underlain material to serve as a subgrade for road construction based on project specifications and Ethiopian Road Authority (ERA) low volume road Specification. From the field tests and laboratory tests carried out, it is observed that the causes of cobblestone road failures of this road section are mainly due to the construction steps/sequence, quality of materials, road construction time, lack of proper design and quality control, absences of drainage structures, lack of highly compaction, lack of accurately fill fine aggregate and suddenly high loads vehicle applied on cobblestone road.