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    Road Pavement Design using Available Granular Material in Central Sudan
    (University of Khartoum, 2020) Fathi Mahmoud Mohammed
    Abstract Sudan national highway network expanded too much in recent years, however, constructed roads are facing many performance failures resulting mainly from un sufficient survey of traffic and construction material. There is no enough data regarding natural material for road construction therefore this research mission started by surveying for quarries which are the main source of road material, access their material characteristics then conduct suitable design templates that can accommodate their specifications so as to become design modalities for future use. We’d divided the study area into three sectors, in each sector we’d suggested a new link road to be designed as pilot road. We'd conducted design work using input data from this research results, in addition to data from National Highway Authority (NHA) laboratories archives and traffic counts carried out on 2012 and 2016 via two well know pavement design methods; US- AASHTO1986 and UK TRL Laboratory Report(LT1132)– (Powell et al., 1984), The final results were analyzed and at last available quarries with good granular material are determined and the best road design method had been recommended with justifications.
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    Towards Geotechnical Map of Sudan Using Artificial Neural Network
    (University of Khartoum, 2014) Safa Abdelrhman Abdelgalil Mohammed
    ABSTRACT Artificial Neural Networks (ANN) are form of Artificial Intelligence, which are mathematical models, inspired by the human brain to enable processing information for producing meaningful solutions. The objective of this study is to build ANN model that predict soil profile based on coordinates and depth at different locations in Sudan. Accordingly, the ANN are used for classification of soil properties at different depths for 417 sites in Sudan. Those sites are divided to five zones depending on the type of soil: 137 sites at Center of Sudan, 28 sites at North of Sudan, 90 sites at South of Sudan, 137 sites at East of Sudan and 108 sites at West of Sudan. Neural Networks are constructed and developed to predict soil layers and estimate some soil parameters. Five models are suggested for the overall data, while other five models are constructed for each zone. Each models contain ten neural network, eight of them to predict soil layers and two to estimate soil parameters. Soil profiles are presented by the aid of Rockwork computer program. The success percentages for the five models of zones data are 67% for West of Sudan, 77% for East of Sudan, 84% for South of Sudan, 77% for North of Sudan and 70% for Center of Sudan. While the total data gives less percentages of success counted as: 33%, 37%, 48%, 34% and 42% for the five zones respectively. The results showed that Artificial Neural Networks can be used effectively as a decision support and source of information for soils profiles. It is more efficient to be used for limited areas. Rockworks program is an efficient tool in drawing soil profile x-section. For the five zones the outputs of the Rockworks program showed that it can be used to give very good presentation for soil profile sections.
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    Estimation of Unconfined Compressive Strength (UCS) of Nubian Formations from Point Load Index and Other Engineering Properties
    (University of Khartoum, ) Abbakar, Mutasim Adam Sandal ; Abdul Karim M. Zein ; Building Technology
    Unconfined compressive strength (UCS) is a fundamental property of rocks that is required in designing the foundations of structures but its determination is tedious, time consuming and expensive. It has been a common practice to estimate UCS using indirect methods because they are relatively cheaper, faster, and more convenient to perform in the laboratory and at site. There is no reported research in this regard for local rocks in Sudan.This study involved extensive laboratory testing of UCS, point load test (PLT) index Is(50), bulk density and water absorption,also determination of the Rock Quality Designation (RQD) of Sudanese Nubian Formation (NF) sandstone and mudstone samples taken from Khartoum State and other areas. Statistical analysis was performed in order to develop reliablecorrelation relationships between the UCS and other parameter of rock.From the analysis of a large number of tests data a reliable linear equation with a UCS to Is(50) factor of 10.18 and 18.07 was developed for the Sudanese NF sandstone and mudstone respectively, and a conversion factor of 11.8 for the combination of two types. Correlations have also been abtained for rough estimation of UCS from bulk density, water absorption and the RQD. As a recommendation from this study the developed empirical relationships for estimating the UCS from other rock parameters can be further checked for validation and improved by future data from future research studies.This estimation is helpful for the preparation of preliminary foundation designs purposes for any engineering project in Sudan with reasonable accuracy.
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    Bearing Capacity of Circular Footing on Stiff Clay Overlying Sand with Geotextile Inclusion
    (University of Khartoum, ) Bahga Mustafa Mohammed Fadl- Allah ; Ahmed Mohamed Elsharief
    The objective of this study is to investigate the potential benefits of using geotextile reinforcement inclusion to improve the bearing capacity of stiff clay over very loose to medium dense sand. Six model load tests were performed on two layered systems, namely stiff clay over very loose, loose, medium dense sand with and without geotextile inclusion between the two layers. Another test was conducted on stiff clay only. The experimental model test set-up consisted of a circular tank, steel plate, load frame, and loading system. The tank was divided into two parts: the upper part, in which the stiff clay was compacted at optimum moisture content and maximum dry density and a bottom part in which the sand was placed at the target relative densities. From the experimental test results, the load-settlement curves were plotted and the ultimate bearing capacity was obtained using Log – Log (L-L), Tangent (TIM), 0.1B and Hyperbolic (HYP) methods. Theoretical approaches were used to compute the ultimate bearing capacities of the tests without and with reinforcement. The test results have shown an increase in the ultimate bearing capacities with increase in the relative densities of the bottom sand layer. The bearing capacity increased significantly with the inclusion of geotextile layer.According to (L- L), (TIM), (0.1B), (HYP) and (Analytical) methods the bearing capacity ratio (BCR) is (1.50,1.50,1.56, 1.70 and 1.067) for the case of very loose sand as bottom layer, (1.13,1.16,1.17,1.23 and 1.057) for loose sand case and (1.12, 1.14,1.16,1.19 and 1.044) for medium dense sand case, respectively. The maximum benefit for the geotextile inclusion was gained when the sand was very loose. Slight improvement in the (BCR)was observed when loose sand or medium dense sand were used as bottom layer. Load - settlements curve of the pure clay test plots above or is identical to the load - settlement curveof stiff clay overlying medium dense sand with geotextile layer.The analytical methods were generally in good agreement with the experimental model test results obtained by the 0.1B method.
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    Evaluation of Quality of Concretes for Some Construction Projects in Sudan
    (University of Khartoum, ) Hmdalsed, Marwa Hussin Alamin ; Osama M. A. Daoud
    This study aimed to evaluate the quality of concrete, which was produced in Sudan during five years’ period from 2003 to 2007, following-up an earlier research that had addressed five years’ period also (from 2008 to 2012). The evaluation is mainly based on the concrete compressive strength achieved and the deviation of the results from the acceptable strength limits that was recognized. The concrete compressive strength was obtained from test results of a 150mm standard cube mold, crushed at the Building and Road Research Institute (BRRI) laboratories at the ages of 7 and 28 days. Collected results for the five years represent crushing test for grade 25 MPa. The data were collected classified and studied. Analysis and evaluation of the data was performed using the computer program (Excel) and the statistical program (SPSS).The evaluation study was carried out based on the requirements of three international codes of practice; The American Institute Code of practice (ACI318) , the European Code of practice (BS EN 206-1:2000) and the Indian Standard (IS 456,2000), in addition to the quality control charts (Shewhart Charts) .The available data results derived from the data analysis software (Excel & SPSS) were assessed based on the pre-mentioned codes “the concrete quality control levels in Sudan for five years’ period (2003 – 2007) was good”. The highest quality levels recognized during the study period were realized in the year (2003) and since then the quality records displayed in a little decreasing during the following years, as clearly illustrated in the study. Application of the above mentioned methods of quality evaluation to the collected strength test results has led to the American standard method overestimates the quality level, the European methods of quality evaluation gives average levels, while the Indian standard underestimates the quality level. This result was expected from the formula of acceptance conditions of the three methods. The lowest quality levels were achieved during the year 2007 according to all evaluation methods. As general the quality level was slightly decreasing from one year to another. These findings are consistent with the results obtained from previous research for five years (2008-2012) as the index reflects a decrease in the level of quality during the ten years starting from the year 2003 up to 2007, to continue to decline down till 2012.