- Title
- Masonry bond strength and the effects of supplementary cementitious materials
- Creator
- Lawrence, S. J.; Sugo, H. O.; Page, A. W.
- Relation
- ASEC 2005: Australian Structural Engineering Conference. Australian Stuctural Engineering Conference 2005: Structural Engineering: Preserving and Building Into the Future (Newcastle, NSW 11-14 September, 2005)
- Relation
- http://www.tourhosts.com.au/ceoconferences_past.asp?Year=2005
- Publisher
- Tour Hosts Pty Ltd
- Resource Type
- conference paper
- Date
- 2005
- Description
- Masonry is inherently strong under compressive stresses and relatively weak under tensile stresses. Compressive strengths of the composite range up to 15 MPa or more, while tensile strengths are typically an order of magnitude less. The tensile strength is also highly dependent on many factors, including the type of masonry unit, composition of the mortar, any admixtures that might be included in the mortar, and workmanship. It is a common misconception that tensile strength is a property of the mortar; it is rather a property of the mortar and masonry unit in combination, expressing how well they are bonded together, and is usually referred to as bond strength for this reason. In practice it is usually measured as a flexural tensile strength of the composite, using a test known as the bond wrench. Bond strength is the primary material property involved in resisting forces produced by wind and earthquake actions on structures. The Australian Masonry Structures standard AS 3700 (Standards Australia, 2001) permits designers to assume a characteristic bond strength of 0.2 MPa without testing on site, and values up to 1.0 MPa if site testing is carried out during construction. A range of deemed-to-satisfy mortar mixes is given in the standard. In Australia and other parts of the world there is an increasing trend to use industry by-products such as ground granulated blast furnace slag and fly ash as supplementary cementitious materials. This use of by-products is beneficial to the environment by reducing the need for landfill, avoiding the need to source new raw materials and reducing greenhouse gas production associated with the manufacturing of Portland cement. Much of the development work for the use of these materials has been carried out in relation to reinforced concrete construction, where the primary action is compression. Relatively little work has been done until now on their effects in masonry mortars, particularly in relation to tensile bond strength. Prior to the publication of Amendment 1 to AS 3700 in May 2002, the standard distinguished between GP Portland cement and GB blended cement and required different proportions of each to be used in the deemed-to-satisfy mixes (see Tables 10.1 and 12.1 of AS 3700). Part of the work described in this paper was used as the basis for amendment to this area of AS 3700.
- Subject
- masonry; mortar; compressive strength; tensile strength; bond strength; supplementary cementitious materials
- Identifier
- http://hdl.handle.net/1959.13/32353
- Identifier
- uon:3003
- Identifier
- ISBN:1877040371
- Language
- eng
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