A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Shrinkage-reducing admixtures and early-age desiccation in cement pastes and mortars
Fundamental studies of the early-age desiccation of cement-based materials with and without a shrinkage-reducing admixture (SRA) have been performed. Studies have been conducted under both sealed and drying conditions. Physical measurements include mass loss, surface tension, X-ray absorption to map the drying profile, internal relative humidity (RH), and autogenous deformation. Interestingly, although the SRA accelerates the drying of bulk solutions, in cement paste with a water-to-cement (w/c) ratio of 0.35, it actually reduces the measured drying rate. Based on the accompanying X-ray absorption measurements and a simple three-dimensional microstructure model, an explanation for this observation is proposed. In sealed systems, at equivalent hydration times, the SRA maintains a greater internal RH and reduces the induced autogenous deformation. Thus, these admixtures should be beneficial to low w/c ratio concretes undergoing self-desiccation, in addition to their normal usage to reduce drying shrinkage.
Shrinkage-reducing admixtures and early-age desiccation in cement pastes and mortars
Fundamental studies of the early-age desiccation of cement-based materials with and without a shrinkage-reducing admixture (SRA) have been performed. Studies have been conducted under both sealed and drying conditions. Physical measurements include mass loss, surface tension, X-ray absorption to map the drying profile, internal relative humidity (RH), and autogenous deformation. Interestingly, although the SRA accelerates the drying of bulk solutions, in cement paste with a water-to-cement (w/c) ratio of 0.35, it actually reduces the measured drying rate. Based on the accompanying X-ray absorption measurements and a simple three-dimensional microstructure model, an explanation for this observation is proposed. In sealed systems, at equivalent hydration times, the SRA maintains a greater internal RH and reduces the induced autogenous deformation. Thus, these admixtures should be beneficial to low w/c ratio concretes undergoing self-desiccation, in addition to their normal usage to reduce drying shrinkage.
Shrinkage-reducing admixtures and early-age desiccation in cement pastes and mortars
Bentz, D.P. (author) / Geiker, M.R. (author) / Hansen, K.K. (author)
Cement and Concrete Research ; 31 ; 1075-1085
2001
11 Seiten, 15 Quellen
Article (Journal)
English
Shrinkage-reducing admixtures and early-age desiccation in cement pastes and mortars
| British Library Online Contents | 2001
Shrinkage-reducing admixtures and early-age desiccation in cement pastes and mortars
| Online Contents | 2001
Early shrinkage of cement pastes, mortars, and concretes
| Springer Verlag | 1980
Chemical Shrinkage of Pastes Made with Shrinkage Reducing Admixtures
| Trans Tech Publications | 2011
Chemical Shrinkage of Pastes Made with Shrinkage Reducing Admixtures
| British Library Online Contents | 2011