Clay mineralogy of modified marginal aggregates

This study, undertaken in 2003-2004, aimed to: study changes produced when additives are mixed with roading aggregates containing swelling clay minerals; and identify the most suitable chemical to use for a particular rock type and the quantity required to achieve particular effects, namely conversion of the clay to a better form, establishment of bonds between particles, strength that is insensitive to water content, minimal drying shrinkage, and permanence. Samples of fresh, partly weathered and weathered rocks of three rock types were taken from four quarries. Cement, lime or Durabind (trade mark) was added to the partly weathered samples at two levels. The untreated and treated samples were analysed. Proctor Needle and CBR testing was performed on the partly weathered samples. Volcanic rocks contained a higher proportion of more readily weathered minerals than greywacke. Drury greywacke was more intensively sheared than Otaika greywacke. All partly weathered materials treated with 3 per cent of additive had satisfactory CBR values. Methylene Blue tests and X-ray diffraction analysis confirmed that 3 per cent additive almost eliminated swelling tendencies. Geochemical studies identified that additives reversed the trends of changing fluid composition caused by weathering. Cement stability was investigated by suspending crushed treated samples in water. Swelling tendency increased over time, but in alkaline conditions, the aggregates returned to 30–70 per cent of their original values after four days. (a)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0478287305
• Authors:
  • BARTLEY, F G
  • HARVEY, C C
  • BIGNALL, G
  • CHRISTIE, A B
  • REYES, A
  • SOONG, R
  • FAURE, K
• Publication Date: 2007

Language

• English

Media Info

• Pagination: 108P
• Serial:
  • Land Transport New Zealand Research Report
  • Issue Number: 318
  • Publisher: Land Transport New Zealand
  • ISSN: 1177-0600

Subject/Index Terms

• TRT Terms: Admixtures; Aggregates; Binders; Building materials; Calcium oxide; California bearing ratio; Cement; Clay; Pavement design; Pavements; Sampling; Sandstones; Swelling soils; Tests
• Uncontrolled Terms: Methylene blue test
• ITRD Terms: 4736: Admixture; 4577: Aggregate; 4948: Binder; 3087: California bearing ratio; 4758: Cement; 4177: Clay; 4574: Lime; 4555: Material (constr); 6250: Methylene blue test; 2955: Pavement; 3055: Pavement design; 6253: Sampling; 4104: Sandstone; 5203: Swelling (soil); 6255: Test
• Subject Areas: Design; Geotechnology; Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways; I31: Bituminous Binders and Materials;

Filing Info

• Accession Number: 01081600
• Record Type: Publication
• Source Agency: ARRB
• ISBN: 0478287305
• Files: ITRD, ATRI
• Created Date: Nov 29 2007 12:46PM