Title: Orifice Rheometer as a Test for Flowing Concrete

Author(s): Peter Bartos

Publication: Symposium Paper

Volume: 68

Issue:

Appears on pages(s): 467-484

Keywords: aggregate size; bleeding ( flow table tests; fresh concretes; mi (tubes); placing; plasticizers; rheol tion; workability. concrete); consistency tests; xing; orifice meters; pipes ogical properties; segrega-

DOI: 10.14359/6487

Date: 1/1/1981

Abstract:
The principle of a free orifice rheometer is used in a development of a device for site-tests of consistency of fresh superplasticized concretes. The new test is designed to complement the '2-point' test and to provide an alternative or even to replace the DIN Flow Table (1) test. Full scale prototype of the Orifice Rheometer was constructed and tests confirmed the capacity of the rheometer to detect differences between fresh flowing mixtures. Using an appropriate orifice the sensitivity of the device was sufficient to indicate excessive bleeding or segregation caused by an overdose of an admixture. Influence of factors such as the composition of a mixture, type and dosage of a superplasticizer on the consistency of a fresh flowing concrete and on its retention were also investigated. In its present form the Orifice Rheometer is a simple, rugged and easily portable apparatus which has provided encouraging results from its first site trials.