New approach to identify compatibility of materials for concrete related to early stiffening

Title: New approach to identify compatibility of materials for concrete related to early stiffening
Author(s): Chiara F. Ferraris, Peter C. Taylor
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: 7
Language: English

Abstract: The measurement of the evolution of mechanical characteristics during the setting period of concrete is needed to control the schedule of construction (pumping, placement, finishing and saw-cutting). This evolution is affected by the compatibility (or incompatibility) of the materials used, such as chemical admixtures and cementitious materials. The Vicat test is the standard test for setting. The information obtained by this test (initial and final set) is largely insufficient, for example, to determine the time during which the material can be pumped or extruded. Our study monitored the cement paste setting period through the variation of an intrinsic material parameter, yield stress. The rheological measurements used were stress growth and the mini-slump. A large set of cements, three supplementary cementitious materials, and two Type A water reducers were used as part of a larger project sponsored by Federal Highway Administration (FHWA) aimed at developing a methodology to select materials for pavement applications. This study’s goal was to determine the feasibility of using either stress growth with a rheometer or mini-slump test to determine incompatibility between materials. The setting times of the cement pastes were monitored for early stiffening (less than 60 minutes) as well as delayed stiffening (several hours). The results of these experiments are discussed and compared. We show that the proposed tests are more sensitive to the setting evolution of cement paste than the Vicat test and provide useful early age information.

Online publication: 2006-08-02
Classification: 3.2 Theme 2: From Fresh to Hardened Concrete
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2351580028.059