Measuring shrinkage of hardening paste with a mini-TSTM

Title: Measuring shrinkage of hardening paste with a mini-TSTM
Author(s): E.A.B. Koenders, G. Leegwater, E. Schlangen
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: 6
Language: English

Abstract: The start of the chemical reaction between cement and water is the moment that concrete starts to develop its properties. More precisely, it is the paste that starts to generate a load-bearing microstructure that exhibits a certain number of mechanical properties. One of the properties generated during hardening is the so-called hardening shrinkage. Quite often, this property is measured from hardening concrete by linear measurements and related to the paste deformation by using mathematical models. The opposite way, by measuring the paste deformation and relate it to the deformation of concrete is another possibility that can be applied. In this paper, a new apparatus called “mini-TSTM” (Thermal Stress Testing Machine) for measuring the hardening shrinkage of paste will be presented and discussed [1]. The device has been developed to measure the hardening deformations directly from the paste. It provides more insight in the contracting forces that act on the paste located in between the aggregates. The mini-TSTM is scaled down from the “full-scale” TSTM machine which is commonly used for measuring the thermal stresses of hardening concrete elements. With the mini-TSTM, the contraction forces can be measured (load controlled) as well as the deformations (deformation controlled) which are mobilized by a paste during hardening. The mini-TSTM is a tool that fits into the moisture controlled specimen chamber of the ESEM with enables the opportunity to sample the paste deformations during hardening as well.
The paper provides the results of the shrinkage deformations and forces for four different cements, measured from a hardening paste with the mini-TSTM. Three similar Blast furnace slag cements are tested which were produced by different mills, and one Portland cement is used as reference cement. Results are compared with measurements from the full-scale TSTM. The results show significant differences between shrinkage measurements from both instruments. The results provide a clear picture of the main effects that play a role when relating shrinkage deformations from paste to concrete or visa versa.

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: 10.1617/2351580028.068