New Zealand pumice as a lightweight concrete aggregate

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Degree name
Bachelor of Engineering
Publisher
University of Canterbury. Engineering
Journal Title
Journal ISSN
Volume Title
Language
Date
1949
Authors
Wilson, D. M.
Abstract

With the present day advance of building science, concrete engineers are beginning to look into the possibilities of making lightweight concrete particularly from lightweight aggregate. There are many reasons for this, the most obvious being of course the reduced dead weight for structural work, which means lower dead load moments in beams and columns. The reduction in dead loads is also accompanied by lower earthquake forces on a building, and lower foundation loads which means lighter and cheaper foundations. In connection with earthquake resistance, a lightweight structural concrete with a low modulus of elasticity is a more flexible and shock resistant building material than normal gravel concrete. It is also desirable to have a material out of which light partition walls can be constructed. Normally, lightweight aggregates owe their lower unit weight to enclosed air. This means that with these aggregates there also comes several other inherent advantages in better thermal and sound insulation. Also several lightweight aggregates, pumice amongst them, provide a concrete which can be nailed and sawn without damage. Pumice has these advantages and one other important one, that of being almost totally fireproof. This is due to two factors, one being the inert nature of the material, and the other and most important, the thermal insulation properties. But before proceeding further it becomes necessary to define what pumice is. One definition states:- “Pumice is a porous glass froth. It was formed from rock fragments thrown into the air from active volcanoes. The sudden expansion of gasses within the rock structure and rapid cooling trapped tiny bubbles of gas that caused it to remain as a spongelike but tough and durable material.”

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Citation
Keywords
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Fields of Research::40 - Engineering::4005 - Civil engineering::400505 - Construction materials
Rights
Copyright D. M. Wilson