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• PARAMETRIC MODELLING ON THE RELATIONSHIPS BETWEEN ATTERBERG LIMITS AND COMPACTION CHARACTERISTICS OF FINE-GRAINED SOILS

  P. Quezon, E. Quezon

  International Journal of Advanced Research in Engineering and Applied Sciences (2019). Worku Firomsa, Prof. Emer Tucay Quezon; (2019). “PARAMETRIC MODELLING ON THE RELATIONSHIPS BETWEEN ATTERBERG LIMITS AND COMPACTION CHARACTERISTICS OF FINE-GRAINED SOILS.” International Journal of Advanced Research in Engineering and Applied Sciences, 8(7), 1-20. https:// www.garph.co.uk

  
  

  Abstract

  Compaction is one of the essential engineering techniques, performed to assure the stability of soils based on specified strength. However, in most construction projects such as large-scale projects, obtaining the desired compaction characteristics, namely optimum moisture content (OMC) and maximum dry density (MDD), becomes time-consuming. In this case, predicting the compaction characteristics from the Atterberg's limits that involve a more straightforward and quicker method of testing becomes a vital task. This study focused on obtaining valid correlations between Atterberg's limit parameters and compaction characteristics of fine-grained soils. A series of laboratory tests for 50 samples conducted for the investigation. Statistical relationships of all the parameters were analyzed. The laboratory test results indicated that both OMC and MDD showed a strong correlation with LL and PL together using multiple linear regressions than with single parameters from single linear regression. Therefore, the study concluded that during the prediction of OMC and MDD from Atterberg's limits, the combined parameters of Atterberg's limits should be used rather than single parameters. It is recommended, the result of this research could be applied in different civil engineering practices, directly related to the parameters to be known.

  Abstract
  Compaction is one of the essential engineering techniques, performed to assure the stability of soils based on specified strength. However, in most construction projects such [...]

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• Evaluation on the Performance of Lowest Responsive Bid Contract and the Quality of Materials Used on Governmental Building Projects in Jimma Town

  E. Quezon

  International Journal of Scientific & Engineering Research (2016). BinyamLetarge, Emer T. Quezon, Yolente C. Macarubbo. Evaluation on the Performance of Lowest Responsive Bid Contract and the Quality of Materials Used on Governmental Building Projects in Jimma Town. International Journal of Scientific & Engineering Research. 2016; 7(12): 60-73

  
  

  Abstract

  Construction industry participants have started recognizing that accepting the least bid price does not guarantee maximum value. Continuous problems of inferior quality of constructing facilities, high incidence of claims and litigation, frequent cost overruns, and use of poor quality of materials have become the main features of Ethiopian’s public construction work contracts. This research was undertaken to evaluate the performance of publicly owned construction projects awarded on a lowest bid awarding system, to determine the effect of advance payment on the contractor’s performance, compare lowest and average bid systems, and check the quality of local construction materials use by lowest price won contracts. A literature review was carried out to identify different practices and floated questionnaire survey and laboratory test was conducted for selected and expected materials. Two alternative bid evaluation methods were discussed and suggested the better one from a performance point of view. The questionnaire was distributed to contractors, clients, consultants, and other related professionals. Additionally, interviews were conducted with them. A total of 88 questionnaires were distributed, including laboratory test results for selected and expected materials found in Jimma town. The data were collected and 80 valid questionnaires were analyzed by using SPSS-20, Excel, and laboratory test results requirement. The study identified that the causes of the poor performance of contractors were won projects with the lowest price; therefore more of the respondents do not like the lowest bidding method. Advance payment is the main solution to support the financial problems of contractors, but instead of paying in cash, purchasing the necessary construction materials is seen as an alternative to protect contractors from using the money for other uses. Obviously known that in the current bid awarding method of Ethiopia, most of the time, in order to be the winner of the bid price should be lesser. This leads the bidder not to get adequate profit, this pushes them to use poor quality of local construction materials. Finally, this work provides valuable information to the Ethiopian government, clients, consultants and contractors, and other stakeholders who desire to improve bidding methods; usage of advance payment; ways to improve performance of contractors, and to protect the project from contractors using poor quality of construction materials. 

  Abstract
  Construction industry participants have started recognizing that accepting the least bid price does not guarantee maximum value. Continuous problems of inferior quality of [...]

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• A Study on the Effect of Time Duration by Vibrating or Tamping Fresh Concrete on the Compressive Strength of C-25 Concrete

  A. Achalu, E. Quezon, G. Macarubbo

  American Journal of Applied Scientific Research (2017). Vol. 3, No. 6: pp. 72-79. doi: 10.11648/j.ajasr.20170306.11

  
  

  Abstract

  Many years ago, consolidation accomplished by laborers wielding a variety of spades, tampers, and similar tools. In Ethiopia, there is no enough knowledge by the laborers, while the site engineers ignored the correct application due to some constraints. The agreement of acceptable vibration level in fresh concrete to which tamping time duration is optimum is an issue to obtain the desired specific compressive strength. This research study aims to evaluate the maximum time length and techniques used to Vibrating or Tamping fresh concrete and its effect on the compressive strength of C-25 Concrete through internal Rodding. Therefore, to study the effects of the period by vibrating or tamping, the needle-type internal vibrator was used to test new concrete cubes based on ACI309R-96. The quality of concrete is important to make physical tests on materials used before any actual experiments to perform. The fresh concrete samples tested by using internal vibration methods and techniques of compaction with different time duration of 1sec, 2sec, 3sec, 4sec, and 5sec. These tests performed by using steel rod in fresh concrete to know the Optimum time of compaction by internal vibration on the cube test of new concrete. Laboratory experiments had been conducted to check the methods and techniques applied to construction sites, as well as site observation on the effects of the vibration time of fresh concrete on the compressive strength and flexural strength of C-25 Concrete with varying vibration time duration and steel rod tamping. Based on the results of cube tests of compressive strength of Concrete Samples have been checked on the 3rd day, 7th day, and 28th day. This research study found out that the Optimum period of compaction was 3sec to produce an acceptable right quality of the concrete mix. Likewise, the flexural strength of the Concrete Sample, when it tested in the laboratory on the 7th day and 28th day, results revealed that the flexural strength improved when vibration time increased, but the amount of water has to be reduced to obtain the desired strength. Finally, Tamping is needed to place fresh concrete in the mold correctly. Furthermore, new concrete produced should match the properties and avoid improper tamping or vibration applications. This situation must not cause differences in the compressive strength of concrete.

  Abstract
  Many years ago, consolidation accomplished by laborers wielding a variety of spades, tampers, and similar tools. In Ethiopia, there is no enough knowledge by the laborers, [...]

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• Influence of Subsurface Courses Materials On Pavement Performance: A Case Study in Yebu-Agaro Road

  E. Quezon

  International Journal of Scientific & Engineering Research (2016). Anteneh Geremew, Prof. Emer T. Quezon, Getachew Kebede. Influence of Subsurface Courses Materials On Pavement Performance: A Case Study in Yebu-Agaro Road. International Journal of Scientific & Engineering Research. 2016; 7(10): 1252- 1260.

  
  

  Abstract

  The properties of subsurface materials would vary from place to place while it is true the performance of pavement along the route also differs. The research study had been undertaken at the Yebu-Agaro road section with the main objective to determine the Influence of Subgrade Soil on pavement performance. In order to realize the desired objective, a systematic methodology was adopted which includes field investigation, field test, and laboratory tests. While the purposive sampling method was used to extract soil samples from the road section that are severely damaged showing different failure types and non-distress surfaces. Those severe types of failures observed along the road section are reflective crack, pothole, rutting, alligator crack, and block crack. From these failure types, five representative samples were extracted at different locations along the failures section and one non-distress pavement of the road section using a manual hand auger. The analyses of soil samples were carried out based on the Geotechnical properties such as wash gradation, Atterberg limit, and Modified proctor test, California Bearing Ratio (CBR) and field test, as well as Axle load analysis. It was found out that the liquid limit of subgrade soil varies from 33% -60.5% and the plasticity index from 20.3% -30.1% while there was a significant increase in moisture content at the field and observed beyond the OMC in the laboratory result due to the distress of pavement affected by water infiltration through cracks, that tend to reduce the dry density. The recorded soaked CBR values of subgrade soil materials range between 8% -13%, which was below the 15% minimum value specified by the ERA manual. However, the existing CBR values of the subgrade soils indicate a poor material used for pavement structures. According to ASSHTO, the soil is classified as A-2-6 and A-7-6 category which means the existing soils are fair to poor as a sub-grade material while USCS classification shows that the soil falls into the SC group. In addition, the failures that are frequently observed on the road surface were significantly influenced by subgrade soil. For the sub-base layer materials, it was noted to have satisfied the minimum requirements as compared with standard specification, except deficiency of its thickness. For the base course materials, inferior qualities of material were used in some sections. The overall results showed that heavy vehicles or traffic loads are one of the major causes of road failure along the study road section. Hence, the influence of other factors such as poor drainage courses, level of groundwater table, variety of geologic materials along the road route, and poor construction materials should be thoroughly addressed before the start of the rehabilitation of the road section in the future. Finally, a possible remedial measure is recommended for every observed failure or distress on the pavement condition of the study area in order to sustain the design life of the pavement. 

  Abstract
  The properties of subsurface materials would vary from place to place while it is true the performance of pavement along the route also differs. The research study had been [...]

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• Investigation of Traffic Accident Prone Areas Related to Existing Road Condition and Driver’s Behavior along Menagesha- Ambo Road Section

  E. (MSc), P. (MSc), E. Quezon

  World Journal of Engineering Research and Technology (2018). Eyob Mekonnen (MSc), Prof. Emer Tucay Quezon and Murad Mohammed (MSc). Investigation of Traffic Accident Prone Areas Related to Existing Road Condition and Driver’s Behavior along Menagesha- Ambo Road Section. World Journal of Engineering Research and Technology. wjert, 2018, Vol. 4, Issue 2, 64-81

  
  

  Abstract

  Traffic accidents worldwide are increasing due to pragmatic vehicle ownership, acquisition, which necessitates daily activities. The primary objective of this research work was to identify the most hazardous location and provide countermeasures that will minimize traffic accident at the designated sites. The scope of the study was limited to Ambo-Ginchi- Addis Ababa road, a total length of the study road section of 87kms. The traffic accident data collected from each Wededa Police station covering the period of 2012-2015. It was analyzed using a Priority value formula for EjereWereda and Holota town, and accident frequency for Ambo wereda, Dendiwereda, and Welmeraweredato rank the traffic accident areas. Based on the results of the analysis, thirteen locations of the road stretch were found to be accident-prone areas. Out of these sites, three of them are in Ambo Wereda, two in Ejerewereda, one in Welmerawereda, and seven in Holota town. The time when most of the accidents occurred from 3:00 PM-6: 00 PM. The primary causes of the accidents were overspeeding, driving without attention, and some unknown reasons. Also, it showed that the drivers’ age group who caused most of the accidents composed of 25-34 years old. Based on the findings of the study, it is concluded that there was a significant increase in the number of crashes in the afternoon. Young drivers are believed to cause more accidents than older ones due to aggressiveness. To minimize the occurrence of accidents along the study road section, it is recommended that provision of speed limit signboards and warning signs at the strategic locations where traffic accident areas are identified to forewarn the overspeeding drivers. It is also recommended that the road agency should have to undertake to widen the lane width of the road, provision of sufficient climbing lane, installation of roadside Delineator, conduct roadside improvements, and repaint faded pavement markings.

  Abstract
  Traffic accidents worldwide are increasing due to pragmatic vehicle ownership, acquisition, which necessitates daily activities. The primary objective of this research work [...]

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• Engineering Properties of Mechanically Stabilized Subbase Material Using Natural Gravel around Jimma Quarry Sites for Unpaved Road Construction

  E. Quezon

  Global Scientific Journals (2017). Almaz Ejeta, Emer Tucay Quezon, Kabtamu Getachew. Engineering Properties of Mechanically Stabilized Subbase Material Using Natural Gravel around Jimma Quarry Sites for Unpaved Road Construction. Global Scientific Journals. GSJ: 2017; 5(5): 93-102

  
  

  Abstract

  Unpaved roads are designed with a small input and are constructed from the nearest available materials as possible. It requires routine and periodic maintenance, and its condition can be significantly affected by a period of excessive traffic volumes or inclement weather conditions. The accurate estimation of maintenance cost is difficult. Many problems occur in the economic analysis of unpaved roads in comparison with paved roads. D effects that may affect unpaved roads are dusty, potholes, stoneness, corrugations, and rutting. Hence, it needs to apply a sufficient stabilization method to strengthen and increase the durability of the unpaved road. Mechanical stabilization is an important application in engineering for different types of construction to improve the performance of road construction materials. The objective of this research was to determine the Engineering properties of natural gravel materials by mechanical stabilization method to be used in subbase material for the unpaved road. The methodology carried out in this research study includes: (a) field visual inspection and sampling of natural gravel materials from three quarry sites around the Jimma area; and (b) laboratory tests to identify the physical and mechanical properties of natural gravel. Based on the laboratory test results, natural gravel materials from the Seka quarry site has an excellent Abrasion resistance of 35.26%, Plasticity Index of 13% a little bit above the upper limit, and good gradation (coarser and less subtle or binder materials), right CBR value. While the Jiren quarry site has a little Abrasion resistance of 52.09%, medium plasticity index, poor gradation (moderate fine material), CBR value of 28.90% which was below 30% minimum requirement, but had good MDD. On the other hand, the Merewa quarry site comprised of a very poor Abrasion resistance of 78.3 4%, Plasticity Index of 2 3.90% which was beyond the upper limit plasticity index of 1 2%, and poor gradation (more fine materials), poor CBR value and poor MDD. Therefore, it is concluded that the natural gravel from the Seka quarry site is suitable for the subbase course. But since road construction around Jimma is booming, the natural gravel from this quarry site would be soon depleted. About this, mechanical stabilization is recommended by blending the natural gravel from the Seka quarry site with 54% by weight with Jiren natural gravel of 46% by weight to meet the minimum requirements for subbase materials.

  Abstract
  Unpaved roads are designed with a small input and are constructed from the nearest available materials as possible. It requires routine and periodic maintenance, and its condition [...]

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• EFFECTS OF MECHANICALLY STABILIZED GRADED ASSORTED COARSE-GRAINED SOILS IN THE PERFORMANCE OF UNPAVED ROAD: A CASE STUDY IN GOFFA ZONE, SAWLA AREA

  E. Esho, E. Quezon

  International Journal of Research - Granthaalayah (2019). Edire Erko Esho, Prof. Emer Tucay Quezon, and Democracy Dilla. (2019). “Effects of Mechanically Stabilized Graded Assorted Coarse-Grained Soils in the Performance of Unpaved Road: A Case Study in Goffa Zone, Sawla Area.” International Journal of Research - Granthaalayah, 7(8), 133-156. https://doi.org/10.5281/zenodo.3380234

  
  

  Abstract

  Road network development in Ethiopia is booming, radiating from Addis Ababa towards NorthSouth directions, and East-West directions, due to the good economic growth of the country. However, there are challenges always facing by the pavement designers, and materials engineers for every road project, specifically the unpaved roads in Goffa Zone. It was because, most parts of the existing unpaved road sections within the study area are heavily damaged, and lack proper maintenance. The source of good quality sub-base course materials limited and becoming depleted. It is for this reason that the research study focused on the investigation of the effects of mechanically stabilized graded assorted coarse-grained soils. Disturbed and undisturbed samples from different quarry sites were considered and tested in the laboratory. Laboratory tests for each location performed, and the results served as control values of the engineering properties of natural soils. The Disturbed samples tested for Gradation, Atterberg's Liquid Limit Tests, and Compaction, while, the undisturbed sample tested for the CBR strength, using the ASTM manual. The results of the assorted materials for the sub-base course were analyzed and compared with the AASHTO and ERA Standard Specifications.

  Abstract
  Road network development in Ethiopia is booming, radiating from Addis Ababa towards NorthSouth directions, and East-West directions, due to the good economic growth of the [...]

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• Identification of Road Traffic Accident Blackspot locations and its countermeasures in Oromia Region, East Wollega Zone

  E. Quezon

  International Journal of Scientific & Engineering Research (2016). Gashaw Fekadu, Prof. Emer T. Quezon. Identification of Road Traffic Accident Blackspot locations and its countermeasures in Oromia Region, East Wollega Zone. International Journal of Scientific & Engineering Research. 2016; 7(10): 1372-1379

  
  

  Abstract

  One of the inputs for the economic development of a country is the expansion of the road network, which is important for the transportation of people and freights from place to place. With this expansion, the occurrences of a road traffic accident is increasing in all parts of the world from time to time, killing the lives of many peoples and damage to properties. This problem is growing with the highest rate in sub-Saharan African countries like Ethiopia. The general objective of this study is to identify the hazardous locations of road traffic accidents and suggest countermeasures to mitigate the occurrence of road accidents. The study area was conducted in the East Wollega Zone of the Southwestern part of Ethiopia in the Oromia Region. Districts exposed to high traffic volume are sampled using the purposive sampling method. Those sampled districts include Digga, Sibbu Sire, Nekemte town, Wayyu Tuka, Guto Gidda, Gobbu Sayyo, Leka Dullacha, and Jimma Arjo. Road accident data are collected from all administrative districts from September 2012 to June 2015 (2005 -2007 E.C), and it was used for the analysis. In addition, a field survey was made to observe the existing geometry, an environment of the roadside, traffic flow regulators, and markings of the road sections. To rank each of the sample districts, evaluation of Priority value had been used consisting of a number of deaths, minor and major injuries that occurred for three years. Based on these parameters, each of the districts was listed from highest to lowest (i.e. Digga, Nekemte town, Sibbu Sire, Wayyu Tuka, Guto Gidda, and Gobbu Sayyo) out of the whole sample districts. This research study had found out that there was a significant increase in terms of the number of deaths occurring due to road traffic accidents as a result of the increase in the coverage of road crashes and their consequences. The major causes of road accidents include over-speeding, ignoring warning posts, road geometry, deterioration of pavement, and roadside environment. In order to minimize the frequency of road traffic accidents at the identified hazardous road locations, countermeasures are recommended, addressing to the concerned agency which includes speed breakers, installation of guardrails at curvatures, installation of hazard light to minimize night-time road accidents, removing roadside obstructions, repair, and maintenance of pavement defects to restore to as-is good condition and building additional facilities for pedestrians in an urban area.

  Abstract
  One of the inputs for the economic development of a country is the expansion of the road network, which is important for the transportation of people and freights from place [...]

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• Investigation on the Suitability of Waste Plastic Bottle as Partial Replacement of Sand in a Cement Tile Production

  E. Haile, E. Quezon, G. Kebede

  American Journal of Civil Engineering and Architecture (2019). Elshaday Haile, Emer Tucay Quezon, and Getachew Kebede, “Investigation on the Suitability of Waste Plastic Bottle as Partial Replacement of Sand in a Cement Tile Production.” American Journal of Civil Engineering and Architecture. 2019; 7(3): 121-127. Doi: 10.12691/ajcea-7-3-1.

  
  

  Abstract

  The rapid growth of the world's construction industry is profoundly affecting the cost of construction materials, as well as the natural resources required to produce the materials and environment. Besides, waste plastic bottles are also becoming another challenge in our surroundings due to their presence in large amounts and their nonbiodegradability property. Even if various methods were attempted to manage this waste, applying it as the partial replacement for different construction materials seems feasible concerning solving the above-stated problems. The objective of this research was to investigate the competency of waste plastic bottles as partial replacement of sand in a cement tile production through conducting workability, dry density, water absorption, and compressive strength test on it at the particular 7th and 21st days of curing. Experimental laboratory method used in this research design for testing some physical and mechanical properties of cement tiles. Other than this comparative method was also applied to compare different properties of controlled cement tile with cement tile made with just 3%-33% ground waste plastic bottle as sand at 3% incremental ratio and also cement tile produced by sodium hypochlorite treated plastic sand. The result showed an increment in the workability of the fresh concrete of the cement tile, decrement in compressive strength, reduction in dry density, and declined water absorption result. Finally, the study concluded the possibility of partial plastic replacement of sand in a cement tile production up to 32.11% replacement ratio for 21st day curing ages and even if the replacement above 32.11% had an adverse effect on the compressive strength and workability of cement tile, it also got an advantage with respect to dry density and water absorption. Also, the study revealed the power of sodium hypochlorite solution in improving the high physical and mechanical properties of cement tile. It recommended for the responsible parties to apply this technology in the real production process of cement tile.

  Abstract
  The rapid growth of the world's construction industry is profoundly affecting the cost of construction materials, as well as the natural resources required to produce [...]

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• Assessment of Factors Affecting Labor Productivity on Road Construction Projects in Oromia Region, Bale Zone

  E. Quezon

  International Journal of Scientific & Engineering Research (2016). Melese Mengistu, Prof. Emer T. Quezon, Getachew Kebede. Assessment of Factors Affecting Labor Productivity on Road Construction Projects in Oromia Region, Bale Zone. International Journal of Scientific & Engineering Research. 2016; 7(11): 899- 910.

  
  

  Abstract

  Road construction in Ethiopia is booming and radiating from Addis Ababa towards North-East and East-West directions to fulfill its long-term development program. Transportation is a prime mover to all sectors in the country to uplift the economic activities of the populace in the locality. In most countries, experience and related literature have revealed that road construction labor costs accounted for 30-60% of the total cost of a project, depending on the terrain and source of materials, labor, and equipment to be utilized. Therefore, construction labor productivity plays a vital role in the performance and profitability of road construction projects. Road sector construction projects in Ethiopia are means through which development strategies are achieved. This research study gives insight on the assessment of the factors affecting labor productivity in road construction projects through a structured questionnaire survey of 83 respondents working on construction road projects in Oromia Region, Bale Zone. Respondents were required to rate how the 61 factors affecting labor productivity with respect to the importance and frequency of occurrence. Understanding these factors is helpful for the construction professionals who work on the initial phase of construction planning in order to efficiently deliver the project plan and to solve poor labor productivity. The results of this survey were then analyzed using the Relative Importance Index (RII) and ranked. The reliability of these 61 factors for assessing the effect on labor productivity was tested by Chronbach’s alpha measurement, and the results indicated that the 30 factors tested are reliable (α= 0.973), and checked by SPSS. The result of this analysis showed that there are 11 groups that have significant impacts on the labor productivity ranked as Material and Equipment Factor with RII=0.819, Manpower and WorkForce Factor with RII=0.764, Management Factor with RII=0.737, Quality Factors with RII=0.720, Supervision Factor with RII=0.699, Safety Factor with RII=0.691, Motivation Factor with RII=0.682, Schedule Factor with RII=0.647, Political Factor with RII=0.620, Natural and environmental Factor with RII=0.566 and Cultural and Religious Factor with RII=0.541. Based on the results of this research study, the top factors that affect labor productivity includes Lack of experience of labor, Material construction shortage, Lack of labor skills, Accident, Tools and Equipment shortage, Labor’s bad habit, Poor site management, Lack of Labor surveillance, Payment delay and Ignore safety precautions. Therefore, this research study suggests that the contractors should assign project managers and construction supervisors with sufficient managerial skills in road construction projects so that when there are any problems which may arise, it would be acted and solved immediately at the project site. On the other hand, the role of the Ethiopian government in project implementation is very significant, which requires proper attention to the productivity issue to enforce hard and fast laws and regulation which help to obtain productive workforce in the road construction industry.

  Abstract
  Road construction in Ethiopia is booming and radiating from Addis Ababa towards North-East and East-West directions to fulfill its long-term development program. Transportation [...]

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