Examining time-zero and early age expansion in pastes containing shrinkage reducing admixtures (SRA’s)

Title: Examining time-zero and early age expansion in pastes containing shrinkage reducing admixtures (SRA’s)
Author(s): Gaurav Sant, Farshad Rajabipour, Pietro Lura, Jason Weiss
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: 20
Language: English

Abstract: New classes of chemical admixtures have been developed over the past two decades that are aimed at reducing the potential for early age cracking in concrete facilities. These admixtures, commonly referred to as shrinkage reducing admixtures or SRA’s, are generally thought to reduce hygral shrinkage by reducing the surface tension of the pore fluid. The reduction in surface tension results in a reduction in the capillary stresses that develop as water is removed from the system during cement hydration or drying. This paper examines early age volume changes that occur in a low w/c paste with and without the addition of SRA. The paste containing SRA shows a slight delay in hydration at early ages, resulting in a delay in initial and final set. After setting, the pastes containing SRA generally show an expansion. This expansion complicates the interpretation of free shrinkage measurements in mixtures containing SRA, leading to confusion in the shrinkage behavior reported in the literature.

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: 10.1617/2351580028.076