Millennium celebrations at world's largest dome; Wrapping up crumbling road surfaces; Coega is high on governments agenda; Worlds biggest water cleanup effort; Engineers must bridge Y2K gap; New method for floor slab construction; Tests on earth-retaining blocks; World's tallest headgear
The challenge for smart technology in civil engineering and general construction is to provide sufficient 'added value' to justify adopting a smart approach. It is essential that the demands for durable, predictable behaviour of materials and structures are not compromised by this approach; rather that significant advantages can be identified, to justify what is almost always an increased initial cost.
This paper descriptionbes tests carried out to determine the early strengths of concretes made with different types of cement, and to evaluate the effects of various percentages of calcium chloride used as an admixture. Curves are presented to serve as a guide to the selection of cement: water ratios suitable for required strengths of concrete.
The paper descriptionbed the initial development of cutback bitumens in stabilizing road base courses and the techniques employed in practice, particular reference being made to the stabilization with bitumen of road sections on the South West Africa coast near Oranjemund.
The paper draws attention to the considerable reduction of surge pressures and the consequent saving of material in pipelines resulting from the use of air-vessels on pumping mains. Comparisons are drawn between the theoretically predicted pressure fluctuations and those actually measured at several points in an existing installation, both with the air-vessel connected and with the air-vessel isolated. For the sake of clarity in discussing discrepancies between theoretical and actual pressures the water hammer phenomenon is outlined and the graphical analysis is explained in some detail using the actual values. With the air-vessel isolated, separation of the water column hampers the comparison but illustrates the result of this phenomenon and the efficacy of the air-vessel in preventing it.