Title: Drying Shrinkage Updated Model for Hardened Chilean Concretes

Author(s): C. Videla

Publication: Symposium Paper

Volume: 246

Issue:

Appears on pages(s): 245-260

Keywords: admixtures; drying shrinkage; portland cement; portland pozzolan cement; prediction models; statistical indicators; strain

DOI: 10.14359/18990

Date: 9/1/2007

Abstract:
This document presents research carried out in Chile for the study of the shrinkage behavior of Chilean concretes. The effect of the volume surface ratio, concrete slump, aggregate and cement type, nominal aggregate maximum size and admixture type were analyzed. A total of 82 different concrete mixtures with a mean cylinder compressive strength between 25 and 40 MPa at 28 days were studied, involving 492 test specimens. The evolution of the drying shrinkage strains was measured up to 1350 days of drying. The applicability of six different prediction models is discussed in the light of the measured shrinkage strains. The prediction of drying shrinkage with ACI-209, B3, CEB-MC90, GL2000 and Sakata 1993 and 2001 models were compared with measured results of Chilean concretes. The results showed that current shrinkage models were not adequate to predict the drying shrinkage of the tested Chilean concretes. However, it was found that for Chilean conditions the best result was obtained with the Sakata models having a coefficient of variation less than 30% when the testing data of all concretes was considered in the analysis. An appropriate methodology to carry out the updating of models was developed, based on the comparison of measured and predicted shrinkage values and the calibration of current proposed models. As a result an updated model to local conditions for use in design phase is proposed.