Edge effect – Essential parameter for the evaluation of volume characteristics of concrete using the wave reflection technique

Title: Edge effect – Essential parameter for the evaluation of volume characteristics of concrete using the wave reflection technique
Author(s): T. Öztürk, O. Kroggel, P. Grübl
Paper category : conference
Book title: 2nd International RILEM Symposium on Advances in Concrete through Science and Engineering
Editor(s): J. Marchand, B. Bissonnette, R. Gagné, M. Jolin and F. Paradis
Print-ISBN: 2-35158-003-6
e-ISBN: 2351580028
Publisher: RILEM Publications SARL
Publication year: 2006
Nb references: 10
Language: English

Abstract: An ultrasonic wave reflection test method was developed to characterize the state of early-age cement-based materials. It analyses the wave reflection from the interface between a well known material and the material to be investigated during the construction and delivers real time data. A large number of investigations have been carried out by the authors concerning the setting and hardening of cement-based materials. A distinct correlation between the development of the wave reflection and the development of mechanical properties of concrete could be drawn. The use in the pre-cast segment production has proven the on-site applicability of this measuring system.
The investigation presented deals with the influence of the edge effect on the evaluation of concrete volume characteristics using the wave reflection technique and how this has to be considered.

For the investigations in the laboratory mortar and concrete specimen were produced and stored under controlled curing conditions. Beneath the wave reflection method the ultrasonic wave velocity method measured in through transmission were performed. The obtained results were correlated with relevant properties of the specimen.

It is obvious that a common direct correlation between the wave reflection data and volume characteristics of concrete is fault-prone. For an appropriate correlation it is necessary to consider the edge effect, which is a measure for the discrepancy between the characteristics of the volume and that of the area near the surface of the specimen, that is investigated by the wave reflection measurements. An improved correlation covering the edge effect was established to monitor the strength gain in concrete.

Keywords: ultrasound; wave reflection; edge effect; concrete; strength gain

Online publication: 2006-08-02
Classification: 3.3 Theme 3: Monitoring, Repair and Maintenance of Concrete Structures
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2351580028.106