The origin of early age expansions induced in cementitious materials containing shrinkage reducing admixtures |
| |
| Authors: | Gaurav Sant Barbara Lothenbach Patrick Juilland Gwenn Le Saout Jason Weiss Karen Scrivener |
| |
| Affiliation: | aDepartment of Civil and Environmental Engineering, 420 Westwood Plaza, 5731 Boelter Hall, University of California, Los Angeles, CA 90095-1593, United States;bEMPA, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Concrete and Construction Chemistry, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland;cEcole Polytechnique Fédérale de Lausanne, Laboratory of Construction Materials, Ecublens, CH-1015, Lausanne, Switzerland;dPurdue University, School of Civil Engineering, 550 Stadium Mall Drive, West Lafayette, IN, USA;eEcole Polytechnique Fédérale de Lausanne, Station 12, MXG-211, Ecublens, CH-1015, Switzerland |
| |
| Abstract: | Studies on the early-age shrinkage behavior of cement pastes, mortars, and concretes containing shrinkage reducing admixtures (SRAs) have indicated these mixtures frequently exhibit an expansion shortly after setting. While the magnitude of the expansion has been noted to be a function of the chemistry of the cement and the admixture dosage; the cause of the expansion is not clearly understood. This investigation uses measurements of autogenous deformation, X-ray diffraction, pore solution analysis, thermogravimetry, and scanning electron microscopy to study the early-age properties and describe the mechanism of the expansion in OPC pastes made with and without SRA. The composition of the pore solution indicates that the presence of the SRA increases the portlandite oversaturation level in solution which can result in higher crystallization stresses which could lead to an expansion. This observation is supported by deformation calculations for the systems examined. |
| |
| Keywords: | Expansion [C] Pore solution [B] Shrinkage [C] Shrinkage reducing admixture X-ray diffraction [B] |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
