This study investigates the durability of basalt fiber following immersion in a range of chemical solutions representative of the concrete medium. The tests were conducted over a 62-day period and the solutions were sodium hydroxide, sodium chloride, sodium sulfate and combinations of the three. Weight loss was observed in all alkali solutions, with the worst being the combination of sodium hydroxide with sodium sulfate. The impact of chloride was minimal in the alkaline environment and reduced the impact of the sulfate when both were present. Microstructure analysis using a Scanning Electron Microscope (SEM) found that the silica structure present in basalt fibers was degraded by the OH-from an alkaline medium. The study suggests the need for modification or treatment of basalt fibers before use as fiber reinforcement in concrete.

The incorporation of high volume fly ash, up to 80%, in concrete without compromising the mechanical and durability properties is potentially very advantageous to the concrete industry in enabling the delivery of economic, social and environmental benefits. To assess this, two high volume fly ash mix designs incorporating 80% class F ultra-fine fly ash, known as microash and hydrated lime, with 10% silica fume and 0 % silica fume have been investigated. Properties investigated are compressive strength, carbonation, chloride ion penetration, water absorption and permeability. The specimens were cured for a maximum period of 90 days to optimize completion of the hydration reaction. The results show that the concrete manufactured with 80% microash exhibited compressive strength in excess of 40 MPa at 28 days and over 70 MPa at 90 days. The material also displayed excellent durability properties compared to the normal Portland cement concrete and other high volume fly ash concretes. The addition of silica fume improved the strength and durability properties of the material.

Many educational institutions have moved or are moving to project-based learning (PBL) in Engineering. Project-based learning and problem-based learning have both advantages and also disadvantages. They are suitable for certain courses and may not be that helpful for certain other courses. In case of courses which require mathematical and analytical skills PBL does not seem to be very useful. As a matter of fact, many students do not seem to learn the basics/fundamentals if PBL method is used. Courses like statics, Mechanics, and structural analysis are the type of courses which can produce graduates without a proper fundamental understanding of the subject matter if PBL is used for the entire course.

No abstract