Title : LIGHTWEIGHT CONCRETE AND SUSTAINABILITY ISSUES
Authors : Theodore W. Bremner
Publication : 2013
Volume :
Pages : 5-Jan
Price : 250
Abstract : History and Future Prospects for Lightweight Aggregates and Lightweight Concrete By Theodore W Bremner, PhD., P.Eng, Professor Emeritus and Honorary Research Professor, Natural vesicular lightweight aggregates have been used since antiquity and their history and uses will be reviewed briefly as well the century old manufactured lightweight aggregates (LWA) made from shale, clay and slate. Also the more recently produced sintered fly ash and pelletized slag will be discussed. The way an essentially weak vesicular aggregate can produce a strong concrete will be explained in terms of the vesicular aggregate being more elastically compatible with the cement matrix as compared to ordinary aggregates. Examples of how LWA and lightweight concrete (LWC) has been used in various types of construction including ships, bridges and buildings will be discussed including the changes needed in the design process to take full advantage of the various forms of its excellent intrinsic properties. Non-structural applications are legion including horticulture where LWA can provide slow release of water and fertilizer when mixed in the soil. For highway construction over soft soil or for fill behind retaining walls the lower density aggregate finds a ready market. Recent developments in making a highly vesicular particle that has a density of even less than water (Ultra lightweight aggregate (ULWA) has an obvious advantage in various applications. The non combustible nature of ULWA as an insulating fill in residential construction has yet to be fully appreciated. Such novel applications as a floating mattress of ULWA and organic soil mixtures that will support a vegetative layer for covering and dewatering mining tailings ponds are showing promise. In a future energy-expensive and perhaps energy-scarce world concerned with global warming, reasons why LWA and ULWA can make a positive contribution will be offered.