WORKABILITY OF FLOWING CONCRETE. ASSESSMENT BY A FREE ORIFICE RHEOMETER

Increased use of fresh very high workability concrete mixes in general construction practice has led to investigations into better 'on-site' methods of assessing its workability. The author describes a method using a free orifice rheometer to measure the rate of flow of the fresh mix. The design of the rheometer and its method of use are discussed in detail. A vertical casing pipe of constant diameter could not be used because a layer of cement paste or mortar would form along the inner surface of the pipe acting as a lubricant. The influence of the content of cement paste and the proportion of fine aggregate on the flow times was investigated experimentally. The results showed an optimum 50 per cent fine aggregate content of the total aggregate used. The influence of a plasticiser on flow times is also investigated. No correlation was found between rheometer flow times and initial spreads measured on the German flow table. The effect on rheometer sensitivity of orifice diameter and the influence of the time interval between the addition of water and the test results are also described. /TRRL/

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00105317
• Corporate Authors:

  Cement and Concrete Association

  Wexham Spring
  Slough SL3 6PL, Buckinghamshire,   England 
• Authors:
  • BARTOS, P
• Publication Date: 1978-10

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: p. 28-30
• Serial:
  • CONCRETE
  • Volume: 12
  • Issue Number: 10
  • Publisher: THE CONCRETE SOCIETY
  • ISSN: 0010-5317

Subject/Index Terms

• TRT Terms: Aggregates; Cement paste; Concrete; Design; Field tests; Flow; Fresh concrete; Measuring instruments; Mix design; Plasticizers; Rheology; Rheometers; Tests; Workability
• Uncontrolled Terms: Flow rate; Particle size distribution
• ITRD Terms: 4577: Aggregate; 6155: Apparatus (measuring); 4767: Cement paste; 9011: Design (overall design); 4750: Fresh concrete; 6226: In situ; 4714: Mix design; 6200: Particle size distribution; 5442: Rheology; 6255: Test; 5941: Workability
• Subject Areas: Design; Geotechnology; Highways; Materials; Planning and Forecasting; I32: Concrete; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00194413
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Jul 11 1979 12:00AM