SVIBOR - Project code: 2-11-410

MINISTRY OF SCIENCE AND TECHNOLOGY

Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69
E-mail: ured@znanost.hr

SVIBOR - Collecting Data on Projects in Croatia

Project code: 2-11-410

RHEOLOGICAL MODEL AND TESTING OF FRESH CONCRETE UNDER VIBRATION

Main researcher: KRSTULOVIĆ, PETAR (70770)

Assistants

RUŽIĆ, SANDRA (900048)

Type of research: basic
Duration from: 06/01/92. to 06/01/96.

Papers on project (total): 6
Papers on project quoted in Current Contents: 2

Institution name: Građevinski fakultet, Split (83)
Department/Institute: DEPARTMENT FOR STRUCTURAL MATERIALS
Address: Matice hrvatske 15
City: 21000 - Split, Croatia

Communication: Phone: 385 (0)21 523 333, 551 475; Fax: 385 (0)21 524 162; E-mail: krstulov@cigla.gradst.hr

Summary: The research includes a further development of theoretical basis for definition of behaviour of fresh concrete under vibration and experimental examination. The research methodology starts from state of the art and the existing apparatus,i.e., vibration rheometer. Further research anticipates a further development of the apparatus and preparation of reference material whose properties could be precisely measurable, according to a generally accepted method, and which could be unambiguously reproducible. Using that material, the constants of the vibration rheometer shall be determined. In the final part of the research, the applicability of method for determination of parameters of rheological model of the specimen shall be verified on all types of fresh concrete, from neat paste to neat aggregate.

Keywords: Specimen, bulk model, volumetric concentration (of ingredient), rheological model, oscillatory system, rheometer-viscometer, reference material.

Research goals: "Knowledge of the theory and mechanism of concrete vibration is surprisingly limited" (ACI Committee 309). Contribution to the theory has been given in Ph. D. thesis of the author of this research (1991). The main objective of this research is a further development of the theory and experimental proof. The composition of concrete shall be presented with bulk model of the specimen.The following results are expected: - Definition of the range of normal specimens, from neat paste to neat aggregate. The specimens in the range are stable and are characterized with flow parameters. Unstability as a main rheological parameter characterizes the specimens outside the range. - Contribution to the knowledge of paste effect, particularly the effect of very fine particles. - Mathematical solution of forced harmonic oscillations of Bingham model, taking approximately into account the inertial forces in the specimen. This is the theoretical basis of the research. - Development of vibration rheometer (viscometer) for determination of the parameters of rheological model of the specimen. The rheometer will consist of cylindrical vessel and the piston with particularly shaped bottom. The apparatus, fresh concrete specimen and the source of vibration should form an unique oscillatory system whose behavior can be presented with Bingham model. - Testing of typical stable specimens in the middle of the range of normal specimens and determination of viscosity parameters and yield parameters under vibration. Approximate or exact determination of plastic viscosity coefficients and yield values. - Application of the vibration rheometer for simple determination of concrete workability.

COOPERATION - INSTITUTIONS

Name of institution: INSTITUT GRAĐEVINARSTVA HRVATSKE
Type of institution: State institute
Type of cooperation: Joint publishing of scientific papers
City: 10000 - Zagreb, Croatia
Name of institution: INSTITUT GRAĐEVINARSTVA HRVATSKE,Poslovni centar Split
Type of institution: State institute
Type of cooperation: Occasional exchange of information
City: 21000 - Split, Croatia

Other information about the project.


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Last update: 09/13/95
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