3 research outputs found
Feasibility of Work-Based Learning Model for Undergraduate Engineering and Technology Programmes in Tanzania
No full textThis study proposes a new approach to teaching-learning in engineering and technology programmes at the undergraduate level in Tanzania, and evaluates its feasibility. The rationale was to improve flexibility in learning by providing learners with alternative programmes to choose from. A conceptual model was introduced showing how the work-based approach can be implemented in training diploma holders to acquire bachelor’s degrees. A survey type of study with a mix of open- and closed-ended questions issued to a sample of 150 finalist students was conducted. The sampled population was all finalyear diploma students pursuing engineering and technology programmes at Mbeya University of Science and Technology in Tanzania. A stratified random sampling approach was followed to obtain the sample. More than 93% of the respondents supported the establishment of work-based programmes. This study, therefore, recommends, amongst other things, that Tanzanian learning institutions should set a pilot programme to test the effectiveness and practicability of this model
The influence of rates of drying and wetting on measurements of soil water retention curves
No full textThe water retention curve is fundamental for a comprehensive description of the hydro-mechanical behaviour of unsaturated soils. The water retention testing system developed at Durham University allows direct and continuous measurement of suction using a high capacity tensiometer, water content determined from mass readings of a digital balance and measurements of volume change. The system was modified to accommodate an additional tensiometer to measure suction at the top besides the existing one at the bottom of the soil specimen. Soil specimens were subjected to drying and wetting following two procedures: discrete measurements carried out in stages to ensure equalisation and continuous measurement at different rates. All suctions measured during continuous and discrete measurements were very close at high saturation degrees. At lower saturation degrees, the suction values from the top and bottom of the specimen deviated from suctions observed in discrete measurements. This deviation in suction values was more evident in accelerated drying and wetting patterns. This can be explained by the fact that water permeability reduces with the decrease in saturation levels
Characterization of gravel borrow pits materials for construction of low volume roads in Dodoma Tanzania
No full textThe study was conducted to investigate suitability of gravel materials from borrow pits which are used for low volume roads construction in Dodoma region Tanzania. Characterization of four borrow pits gravel materials from Dinda, Mahomanyika, Nkulabi and Ntyuka were conducted. Blending process of the borrow pits materials with sand from Ihumwa and clay from Michese in order to improve missed engineering properties were conducted. The GC, SP and PI were 25.4 units, 391.3 units and 16% for Dinda, 32.3 units, 56.0 units and 10% for Mahomanyika, 33.7 units, 148.1 units and 14% for Nkulabi and 32.8 units, 111.2 units and 13% for Ntyuka borrow pit materials respectively. Results of CBR for source materials were 14%, 16%, 29%, and 30% for Dinda, Nkulabi, Mahomanyika, Ntyuka borrow pits materials respectively. The results indicated that all source gravel materials did not comply with requirements as gravel materials for low volume roads. This is because Mahomanyika borrow pit materials has low SP values which required blending with clay materials and Dinda, Nkulabi and Ntyuka have high PI values which required blending with sand. Results of GC, SP and PI for the blended materials were 20.1 units, 259.9 units and 12% for 75Dind25San, 31.3 units, 126.7 units and 11.9% for 85Mah15Cla, 31.0 units, 120.0 units and 11.2% for 80Nku20San and 30.3 units, 104.2 units and 10.4% for 80Nty20San respectively. CBR values of blended materials were 19%, 32%, 16% and 26%, for 75Din25San, 85Mah15Cla, 80Nku20San and 80Nty20San respectively. It has been investigated that all blended materials are suitable for construction of low volume roads in Dodoma region since they have satisfied GC, SP, PI and CBR requirements as surfacing materials for construction of low volume roads. It is important to characterized source materials before use in order to investigate engineering properties. In case source materials lack some engineering properties it is necessary to blend with other materials in order to improve missing engineering properties before use.
Keywords: Gravel Materials, Low Volume Roads, Characterization, CBR, Blending
