STIFFNESS OF CONCRETE MADE WITH GRANITE AND ANDESITE AGGREGATES

Concretes containing two types of aggregate, crushed granite and crushed andesite from the witwatersrand area, were studied in order to quantify the influence of aggregate stiffness and volume concentration on elastic properties. Representative paste and mortar mixes were extracted from the basic concrete mixes, and elastic properties of these materials, as well as of rock core specimens from the two aggregate types, were determined. The study involved correlations of concrete properties with predictions using various two-phase models based on micro-rheological principles. It was found that granite concretes conformed best with a model assuming no bond between paste and aggregate (the series model), while andesite concretes were best modelled by the hobbs model, which assumes full bonding between the phases. Regarding practical design, the tests have partially validated the recently introduced empirical expression in BS 8110, with k-o values (an aggregate stiffness factor related to the elastic modulus of the aggregate and to its volume concentration) of 19 gpa and 27 gpa being recommended for the particular granite and andesite aggregates respectively. (TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00097845
• Corporate Authors:

  South African Institution of Civil Engineers

  Gillstraat 18A, Observatory 2198
  Yeoville,   South Africa 
• Authors:
  • Grills, F
  • Alexander, M G
• Publication Date: 1989-9

Language

• Afrikaans

Media Info

• Pagination: v.p.
• Serial:
  • CIVIL ENGINEER IN SOUTH AFRICA
  • Volume: 31
  • Issue Number: 9
  • Publisher: South African Institution of Civil Engineers
  • ISSN: 0009-7845

Subject/Index Terms

• TRT Terms: Aggregates; Concrete; Feldspar; Granite; Mix design; Modulus of elasticity; Stiffness; Stress (Psychology); Stresses
• ITRD Terms: 4577: Aggregate; 4755: Concrete; 4122: Felspar; 4101: Granite; 4714: Mix design; 5919: Modulus of elasticity; 5931: Stiffness; 5544: Strength (mater); 5575: Stress (in material)
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00497678
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS, ATRI
• Created Date: Sep 30 1990 12:00AM