Effect of the synergy of two shrinkage reducing admixtures

Title: Effect of the synergy of two shrinkage reducing admixtures
Author(s): António B. Ribeiro, Ana Carrajola, Arlindo Gonçalves, Fernando Branco
Paper category : conference
Book title: International RILEM Conference on Volume Changes of Hardening Concrete: Testing and Mitigation
Editor(s): O. M. Jensen, P. Lura, K. Kovler
Print-ISBN: 2-35158-004-4
e-ISBN: 2351580052
Publisher: RILEM Publications SARL
Publication year: 2006
Pages: 223 - 230
Total Pages: 8
Nb references: 5
Language: English

Abstract: Concrete shrinkage develops deformations and stresses in structure elements which should be considered in structural design. The values given in codes are estimated average values, for traditional materials. However, concrete may exhibit much lower values, namely when using shrinkage reducing admixtures (SRA). In the last decade, SRA have been developed, which main mechanism of action is the reduction of surface tension of the interstitial concrete pore liquid. This reduction leads to a decrease of the hydrostatic tension, which is the main phenomenon in concrete shrinkage for high relative humidity. Since the concrete humidity is usually high in the first months, a significant decrease of concrete shrinkage is expected when using this type of admixtures. With the objective of a higher shrinkage reduction, mortars with a synergy of two different SRA, based in distinct molecules, were tested in comparison with mortar with only one SRA. Results indicate a cumulative effect in shrinkage reduction which allows a deeper reduction of shrinkage, when compared with mortars with only one admixture.

Online publication: 2006-07-30
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2351580052.024