A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Ultrasonic measurement of viscoelastic shear modulus development in hydrating cement paste
A test procedure for measuring changes in amplitude and phase of SH ultrasonic waves from the interface between fused-quartz and cement paste samples is presented. The phase change is determined from the temporal shift in the reflected signal relative to the incident signal. The sensitivity of the measured parameters to changes in acoustic impedance of the materials in contact with fused-quartz is evaluated for different angles of incidence. It is shown that a reflection measurement at normal incidence at nano-second temporal resolution does not provide sufficient sensitivity to measure the viscous component of shear modulus of low viscosity fluids and cannot be applied to cement paste while it is in a fluid state. Monitoring the measured amplitude and phase at oblique angle of incidence allows for measuring fluids with acoustic impedance comparable to cement paste. The reflection measurements are used to determine the evolution of elastic and viscous components of shear modulus cement paste with time. Influence of sampling rate and temperature effects on the phase measurements are evaluated and shown to be significant. It is shown that the initial loss of workability of cement paste through setting process is associated with a larger relative increase in the viscous component of shear modulus. Following the initial rapid rise of the viscous component of shear modulus, there is a larger relative increase in the elastic component, which can be related to the emergence of a solid structure capable of retaining an imprint.
Ultrasonic measurement of viscoelastic shear modulus development in hydrating cement paste
A test procedure for measuring changes in amplitude and phase of SH ultrasonic waves from the interface between fused-quartz and cement paste samples is presented. The phase change is determined from the temporal shift in the reflected signal relative to the incident signal. The sensitivity of the measured parameters to changes in acoustic impedance of the materials in contact with fused-quartz is evaluated for different angles of incidence. It is shown that a reflection measurement at normal incidence at nano-second temporal resolution does not provide sufficient sensitivity to measure the viscous component of shear modulus of low viscosity fluids and cannot be applied to cement paste while it is in a fluid state. Monitoring the measured amplitude and phase at oblique angle of incidence allows for measuring fluids with acoustic impedance comparable to cement paste. The reflection measurements are used to determine the evolution of elastic and viscous components of shear modulus cement paste with time. Influence of sampling rate and temperature effects on the phase measurements are evaluated and shown to be significant. It is shown that the initial loss of workability of cement paste through setting process is associated with a larger relative increase in the viscous component of shear modulus. Following the initial rapid rise of the viscous component of shear modulus, there is a larger relative increase in the elastic component, which can be related to the emergence of a solid structure capable of retaining an imprint.
Ultrasonic measurement of viscoelastic shear modulus development in hydrating cement paste
Ultraschallmessung der Entwicklung des viskoelastischen Schubmoduls beim Wasserabbinden von Zementpaste
Wang, Xiaojun (author) / Subramaniam, Kolluru V. (author) / Lin, FengBao (author)
Ultrasonics ; 50 ; 726-738
2010
13 Seiten, 18 Bilder, 3 Tabellen, 26 Quellen
Article (Journal)
English
Modeling the apparent and intrinsic viscoelastic relaxation of hydrating cement paste
| Online Contents | 2015
Fractal microstructures in hydrating cement paste
| British Library Online Contents | 1999
Fractal microstructures in hydrating cement paste
| Tema Archive | 1999
Modelling elasticity of a hydrating cement paste
| Online Contents | 2007
Modelling elasticity of a hydrating cement paste
| British Library Conference Proceedings | 2008