Bitumen emulsion cold-mixtures as a feasible pavement construction material in Tanzania

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University of Dar es Salaam
The purpose of this research was to establish the extent to which Bituminous Cold-Mixes (BEMIX) can be used in pavement construction in Tanzania with the objective of overcoming some of the disadvantages that are associated with the use of Hot -mixes. Most of the flexible pavements in Tanzania are constructed using Bituminous Hot-Mixes, while a few of them consist of Surface Treatments. Although the conventional Bituminous Hot-Mixes are generally known to be stronger and more durable than other types of mixes, they are associated with some economic disadvantages, environmental hazards and safety problems. The Research consisted of sampling some of the commonly used rfoad aggregates and some locally blended Bitumen Emulsions; making trial mixes and evaluating their stability and strength. In the course of this study, it has been found that BEMIX can be successfully employed as a paving mixture for the construction of base as well as surfacing courses. Test results have shown that BEMIX can attain soaked Marshall values of between 5 and 9 kN after curing in Oven at 40 °C for 24 hours, followed by soaking in water for another 24 hours. From the Test results obtained, it has been evident that BEMIX can be practically used in construction of pavements for any of the current classes and types of Traffic. The condition for satisfactory performance of BEMIX especially for high-class type of pavements is the strict adherence to proper Mix Design procedures, and appropriate construction methods. As the use of BEMIX is still new in Tanzania, further research is needed to establish the performance of different mineral aggregates, which are available in various parts of the country, when mixed with the available Bitumen emulsions. The present Ministry of Works Materials Manual and that of Asphalt Institute [1987], provide Design Criteria for Bitumen Emulsion cold mix for base course only. There is therefore a need to establish appropriate Mix design criteria, for BEMIX to use in construction of pavement surface course in Tanzania. Use of BEMIX in Tanzania is thus feasible, and is highly recommended for it is economically, environmentally as well as user friendly.
Available in print form,East Africana Collection, Dr. Wilbert Chagula Library, Class mark (THS EAF TE270.T34M42)
Bitumen, Pavements, Maintenance and repair, Tanzania
Mgani, S. I. R. (2000) Bitumen emulsion cold-mixtures as a feasible pavement construction material in Tanzania, Master dissertation, University of Dar es Salaam. Dar es Salaam