| Title |
Rheological behaviour modelling of cement paste with nanotubes and plasticizer / |
| Authors |
Skripkiūnas, Gintautas ; Karpova, Ekaterina ; Dauksys, Mindaugas |
| DOI |
10.14382/epitoanyag-jsbcm.2019.32 |
| Full Text |
|
| Is Part of |
Epitoanyag - journal of silicate based and composite materials.. Budapest : Scientific Society of the Silicate Industry. 2019, vol. 71, iss. 6, p. 184-189.. ISSN 0013-970X |
| Keywords [eng] |
cement paste ; plasticizer ; nanotubes ; yield stress ; viscosity ; rheological model |
| Abstract [eng] |
Rheological properties of cement pastes determine the technological properties of concrete mixtures and have a significant influence on the concrete placement, including pumping, selfcompacting, 3D printing and others. The different types of additives and admixtures allow managing by the technological and rheological properties of cement systems. The lignosulphonate (LS), sulfonated naphthalene and melamine formaldehyde (NF), polycarboxylate ether (PCE) and acrylic polymer plasticizers, which change the consistency of concrete mixtures, are more widely used like plasticizing admixtures in construction practice nowadays. The carbon nanotubes are a perspective tool in managing by the rheological and technological properties of concrete in view of their outstanding mechanical, thermal, optical, electrical and some other properties. The rheological behaviour of cement pastes with nanotubes and different types of polymer plasticizing admixtures was analyzed in the course of the current research using rotating rheometer with coaxial cylinders. The cement pastes and concrete mixtures have the non-linear shear rate and shear stress dependence and require the application of non-linear rheological models such as Herschel-Bulkley or modified Bingham model. The approximation of experimental flow curves and evaluation of the rheological parameters such as yield stress, plastic viscosity and pseudoplastic indexes were performed based on the Herschel-Bulkley model in the course of the present research. The testing of cement pastes in the presence of different plasticizing admixtures with and without MWCNT revealed the differences in rheological parameters depended on applied plasticizer. The molecular structure of plasticizing admixtures, small size, high aspect ratio and surface area of MWCNT, physical and chemical interactions between plasticizers and MWCNT can be a reason of observed changes in the rheological properties of cement pastes. The addition of MWCNT contributes to the obtaining of the cement paste of low dilatancy with definite flowability, yield stress and viscosity. |
| Published |
Budapest : Scientific Society of the Silicate Industry |
| Type |
Journal article |
| Language |
English |
| Publication date |
2019 |
| CC license |
|
