Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 7 Articles
Currently, Global Positioning System (GPS) techniques are becoming a much larger part of the\nsurveying industry. Many companies are now using GPS in their everyday work activities. The Real\nTime Kinematic (RTK) positioning is an integral part of topographic surveys, road surveying, constructions\nand most civil engineering applications. Normally, RTK can be used to collect the positioning\ndata successfully and quickly. The civil and construction projects are designed in ground\ndistances while RTK measurements are done in grid coordinate system, in which the distances\nbetween points are different from ground. The RTK measurements should be converted to ground\nfor compatibility with the designed. In this paper, the accuracy of three alternatives for converting\nRTK measurements to ground was studied. These alternatives are, using scale factor, using two\nground reference points and using Low Distortion Projection (LDP) surface. For the accuracy investigation\npurpose, a traverse of 14 points elongated for a distance of about 1400 m was constructed.\nIts coordinates were measured using total station, then the misclosure error was computed\nand the coordinates were adjusted. The traverse points coordinates were measured again\nusing RTK_GPS considering one of them as base point. The three studied alternatives were applied\nand the results were compared. The results show that the accuracy of the three alternatives is\nranging from 2.1 to 2.9 cm in the relative position of points to the base point. For absolute position\naccuracy, the two ground reference points alternative is the most accurate alternative with an average\nerror of 3.8 cm while the other two alternatives are almost the same with an average error\nof 12.3 cm....
The main purpose of this article is to choose among advanced rheological models used in the\nFrench rational design, one that best represents the viscoelastic behavior of asphalt mixtures\nmixed with aggregates of Senegal. The model chosen will be the basis for the development of\ncomputational tools for stress and strain for Senegal. However, the calibration of these models\nneeds complex modulus test results. In opposition to mechanical models the complex modulus can\ndirectly characterize the viscoelastic behavior of bituminous materials. Here determination is\nperformed in the laboratory by using several types of tests divided into two groups: homogeneous\ntests and non-homogeneous tests. The choice of model will be carried out by statistical analysis\nthrough the least squares method. To this end, a study was carried out to ââ?¬Å?Laboratory of Pavement\nand Bituminous Materialsââ?¬Â (LCMB) with asphalt concrete mixed with aggregate from Senegal\nnamed basalt of Diack and quartzite of Bakel. In this study, the test used to measure the complex\nmodulus is the Canadian test method LC 26-700 (Determination of the complex modulus by tension-\ncompression). There mainly exist two viewing complex modulus planes for laboratory test\nresults: the Cole and Cole plane and the Black space. The uniqueness of the data points in these\ntwo areas means that studied asphalt concretes are thermorheologically simple and that the principle\nof time-temperature superposition can be applied. This means that the master curve may be\ndrawn and that the same modulus value can be obtained for different pairs (frequency- temperature).\nThese master curves are fitted during the calibration process by the advanced rheological\nmodels. One of the most used software in the French rational design for the visualization of complex\nmodulus test results and calibration of rheological models developed tools is named Visco-\nanalysis. In this study, its use in interpreting the complex modulus test results and calibration...
In this research the effect of Coconut (CN) fibre on the fresh and thermo gravimetric properties of\nself-compacting concrete (SCC) at elevated temperatures was investigated experimentally and\nstatistically. The mixtures containing cement, water, fly ash, fine aggregate, coarse aggregate and\nsuper plasticizer with the addition of CN fibres (0%, 0.05%, 0.10 %, and 0.15%) by volume of the\nmixtures were prepared. The fresh and thermo gravimetric properties of the SCC specimens were\ndetermined after mixing at elevated temperatures (200Ã?Å¡C, 400Ã?Å¡C, and 600Ã?Å¡C) testing in a laboratory.\nThree control specimens with 0% CN fibres were used for every mixture of SCC. Regression\nmodels were developed to determine the responses. The optimum of the CN fibres was measured....
Labour productivity output in civil engineering construction projects is an important aspect of civil engineering profession world-wide over many centuries. The use of civil engineering construction materials plays 60% role, while labour productivity output take 40% of the construction projects execution in construction industry. This account for the reason why multi-national companies spend huge sum of money every year to train and retain labour work force that is being employed for daily execution of activities that are carryout within the organization. Understanding and dealing with the human elements at construction sites is the very essential unit for a better performance and working environment, especially in Nigeria where labour productivity output has less regards. This paper assess labour productivity in civil Engineering construction projects in Nigeria, factors affecting proper labour productivity output, and the way forward....
The objective of the study is to evaluate the performance of porous asphalt using waste recycled concrete material and explore the\neffect of adding Gilsonite to the mixture. Asmany as 90Marshall specimens were prepared with varied asphalt content, percentage\nof Gilsonite as an additive, and proportioned recycled and virgin coarse aggregate. The test includes permeability capability and\nMarshall characteristics. The results showed that recycled concrete materials seem to have a potential use as aggregate in the hot\nmix asphalt, particularly on porous hot mix asphalt. Adding Gilsonite at ranges 8ââ?¬â??10% improves the Marshall characteristic of the\nmix, particularly its stability, without decreasing significantly the permeability capability of the mix.The use of recycled materials\ntends to increase the asphalt content of the mix at about 1 to 2% higher.With stability reaching 750 kg, the hot mix recycled porous\nasphalt may be suitable for use in the local roads with medium vehicle load....
The main goal of this paper is to describe the mechanical behavior of the CDW recycled concrete in\ncompression, using an isotropic damage model adapted to the variation of the replacement rate of\nnatural aggregates by recycled ones. The isotropic model by Mazars was used as a constitutive\nequation for the CDW concrete and its adjustment parameters, A and B, were written as quadratic\npolynomials according to the aggregates replacement rate. The model was evaluated for conventional\nand recycled concretes. For the latter ones, the aggregates replacement ratios evaluated\nwere 50% and 100%. The results show good approximation between the analytical and numerical\nvalues obtained with the adapted isotropic damage model and experimental concrete results for\nboth compressive and flexural strength....
In general, of construction projects, utility anti-seismic technologies, such as hydraulic tie rod or\ntie rod structural vibration control system, assess efficiency and safety in node structures from\nearthquakes risk. According the building construction framework, we exanimate, with experiments,\nthe mechanism of reaction and a patent idea of anti-seismic system with potential conclusions,\nthrough using different methods, such as of horizontal seismic insulation, design with elongated\nrigid columns and design columns without ductility. We provide that we made strong foundation\nin earthquakes, solar-wind and utility power structural systems and tornados effects in\nlightweight constructions. We suggest that may fix to existing or under design construction like\nbridges....
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