Thixotropic Properties of Self-consolidating Concrete

Self-consolidating concrete (SCC) has gained
increased acceptance in the construction industry
due to its high fluidity. It has thus become
essential to better understand the lateral pressure
that can be developed on vertical formworks. The
approach based on assuming that the plastic concrete
exerts full hydrostatic pressure until setting time
results in increased construction costs and limits
the rate of rise of the concrete in the formwork.
This book presents the various parameters affecting
SCC lateral pressure. Variations in pressure are
found to be highly affected by the development of
shear strength properties, namely the internal
friction and cohesion. Higher degree of internal
friction limits the maximum initial pressure
measured right after casting. On the other hand, the
development of cohesion with time was found to
directly affect the rate of pressure drop following
casting. The SCC formwork pressure can well be
estimated by
the magnitude of thixotropy. The higher the degree
of thixotropy, the less the concrete develops
pressure right after casting and the faster is the
rate of pressure drop over time.

Autorentext

Dr. J. Assaad is Professor of Civil Engineering at Notre Dame University and R&D Manager at Holderchem Building Chemicals S.A.L., Lebanon. His research interests include technology of chemical and mineral admixtures, grinding aids for Portland cement, rheology, concrete repair and injection, formwork pressure, and durability.

Klappentext

Self-consolidating concrete (SCC) has gained increased acceptance in the construction industry due to its high fluidity. It has thus become essential to better understand the lateral pressure that can be developed on vertical formworks. The approach based on assuming that the plastic concrete exerts full hydrostatic pressure until setting time results in increased construction costs and limits the rate of rise of the concrete in the formwork.This book presents the various parameters affecting SCC lateral pressure. Variations in pressure are found to be highly affected by the development of shear strength properties, namely the internal friction and cohesion. Higher degree of internal friction limits the maximum initial pressure measured right after casting. On the other hand, the development of cohesion with time was found to directly affect the rate of pressure drop following casting. The SCC formwork pressure can well be estimated by the magnitude of thixotropy. The higher the degree of thixotropy, the less the concrete develops pressure right after casting and the faster is the rate of pressure drop over time.