Effect of Mineral Admixtures on Mechanical Properties of High Strength Concrete Made with Locally Available Materials

This paper reports a part of an ongoing experimental laboratory investigation being carried out to evaluate the mechanical properties of concrete made with mineral admixtures and local Jordanian materials. Various percentages of Silica Fume (SF) and Fly Ash (FA) were added at different water/cementitious (w/cm) ratios. Concrete specimens were tested and compared with plain concrete specimens at different ages. Results indicated that compressive as well as flexural strengths increased with mineral admixture incorporation. Optimum replacement percentage is not a constant one but depends on the w/cm ratio of the mix. SF contributed to both short and long-term properties of concrete, whereas, FA showed its beneficial effect in a relatively longer time. Adding of both SF and FA did not increase compressive strength in the short-term, but improvements were noticed in the long-term. Compared with compressive strength, flexural strength of SF concretes has exhibited greater improvements. Relationships between the 28-day flexural and compressive strengths have been developed using statistical methods. It is concluded that local concrete materials, in combination with mineral admixtures, can be utilized in making High Strength Concrete in Jordan and such concrete can be effectively used in structural applications

Characterization of cell phone use while driving in Jordan

A substantial body of research has shown that the use of cell phones while driving can impair driving performance thus representing a relevant traffic safety issue. The conducted studies have indicated that with an increase in general cell phone use, phoning while driving has also grown. For around 80% of Jordan's population that own cell phones, phoning while driving has become a legitimate concern for potential safety hazards. In order to effectively target interventions towards the drivers using cell phones while driving, information about the characteristics of these respondents is needed. The present study investigates the extent of cell phone use on Jordan's roads and the characteristics of drivers who use cell phones while driving. The data was collected using a questionnaire survey to examine the relationship between phoning while driving and driver demographics, driving experience and exposure and characteristics of users. Among all participants, the study demonstrated that those who reported the use of hands‐free devices tended to use the cell phone more often and for a longer duration of time. Further, male drivers tended to use the cell phone while driving more frequently and for longer duration compared with female drivers. In regards to pulling off the road while using the cell phone, the study found this practice to be more prevalent among females, older drivers and more educated drivers. The study has also revealed other findings that are important for characterizing the trend towards using the cell phone while driving in Jordan. First published online: 10 Feb 201

Environmental Enhancement through Utilization of Silica Fume as a Partial Replacement of Fine Aggregate in Concrete

The proper disposal of silica fume, an industrial by product waste, is one of the major issues for environmentalists world wide since dumping of silica fume as a waste material may cause severe environmental problems and hazards. An experimental research program was carried out to study the utilization of silica fume in concrete instead of dumping it as a waste material. Fine aggregate was partially replaced with 5, 10, and 15% of silica fume by weight. Compressive strength of concrete specimens, at three water/cement ratios of 0.50, 0.55, and 0.60, were compared with concrete specimens, with no silica fume, at 7, 28, and 56 days age. Specimens were cast and tested in accordance to ASTM standards. Test results indicated improvement, of up to 21.6%, in the compressive strength properties of concrete by the inclusion of silica fume as a partial replacement of fine aggregate. Compressive strength of concrete containing 10 to 15% silica fume was acceptable for structural applications since the minimum compressive strength was more than 27 MPa at 28 days. Environmentally speaking, results suggest that silica fume, used as a partial replacement of fine aggregate, could be conveniently used in concrete industry as a means of waste product utilization and as a saving of fine aggregate resources. Keywords: Concrete, Silica fume, Compressive strength, Fine aggregate, environmental hazards, Waste utilizatio

Characterization of cell phone use while driving in Jordan

A substantial body of research has shown that the use of cell phones while driving can impair driving performance thus representing a relevant traffic safety issue. The conducted studies have indicated that with an increase in general cell phone use, phoning while driving has also grown. For around 80% of Jordan’s population that own cell phones, phoning while driving has become a legitimate concern for potential safety hazards. In order to effectively target interventions towards the drivers using cell phones while driving, information about the characteristics of these respondents is needed. The present study investigates the extent of cell phone use on Jordan’s roads and the characteristics of drivers who use cell phones while driving. The data was collected using a questionnaire survey to examine the relationship between phoning while driving and driver demographics, driving experience and exposure and characteristics of users. Among all participants, the study demonstrated that those who reported the use of hands-free devices tended to use the cell phone more often and for a longer duration of time. Further, male drivers tended to use the cell phone while driving more frequently and for longer duration compared with female drivers. In regards to pulling off the road while using the cell phone, the study found this practice to be more prevalent among females, older drivers and more educated drivers. The study has also revealed other findings that are important for characterizing the trend towards using the cell phone while driving in Jordan