WATER ABSORPTION INTO WHITE CEMENT MORTARS BY CAPILLARITY

Author(s): Chunsheng Zhou, Fangzhou Ren, Wei Wang
Paper category: Proceedings
Book title: Proceedings of the International RILEM Conference
Materials, Systems and Structures in Civil Engineering 2016
Segment on
Moisture in Materials and Structures
Editor(s): Kurt Kielsgaard Hansen, Carsten Rode and Lars-Olof Nilsson
Print-ISBN: 978-2-35158-230-5
ISBN: 978-2-35158-178-0
e-ISBN : 978-2-35158-179-7
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 14-23
Total Pages: 10
Language : English

Abstract: Water transport property for cement-based materials is very critical and should be paid great
attention in the quantitative analysis of durability and service life prediction. In this paper, the
pore size distribution (PSD) of two white-cement mortars is quantified by Mercury Intrusion
Porosimetry (MIP) and Nuclear Magnetic Resonance (NMR) techniques. Before and after
capillary absorption, the storage characteristics and distribution profile of absorbed water are
observed by NMR technique. Furthermore, the hydraulic diffusivity is derived from the
measured water content profile and capillary sorptivity. It is found that the PSD determined
from MIP and NMR show similar bi-model trends with some observable differences, which
may be caused by the obvious difference of sample sizes. The capillary sorptivity can only
capture the absorption ability of small capillary pores of radius about 5nm-300nm. In another
aspect, it is difficult to accurately calculate the hydraulic diffusivity through the Bruce and
Klute equation. While the Zhou model can be used instead to determine hydraulic diffusivity
of exponential law with good accuracy for cement-based materials.