Application Of Positron Annihilation Lifetime
Spectroscopy To Nano-characterisation Of
Polymer-modified Mortars
Author(s)
P. Guagliardo, A. J. Klemm, S. N. Samarin & J. F. Williams
Abstract
Positron annihilation lifetime spectroscopy (PALS) has been applied to study the
microstructural features of immature cement mortars. Two types of cement
mortars containing superabsorbent polymers (SAPs) were studied, in addition to
Ordinary Portland Cement (OPC). The ortho-positronium lifetimes for all
samples were in the range of 1.70-1.73 ns, values that are close to that of free
water (1.7 ns) and hence suggest the presence of water-filled pores. Periodic
lifetime measurements showed that the intensity of this component decreased
slightly over a period of four weeks, indicating water loss associated with the
curing process, evaporation or a combination of the two.
Keywords: cement mortar, superabsorbent polymer, positron annihilation
lifetime spectroscopy, positronium, porosity, hydration, curing.
1 Introduction
Cement is a material of immense practical importance, but in spite of its almost
ubiquitous use, its microstructural characterisation still proves to be problematic.
The complexity of the problem is enhanced when the composition of cement is
modified through the use of auxiliary agents. Ordinary Portland cement is a
combination of gypsum (CS*H2) and clinker. Gypsum acts to prevent rapid
setting of the cement paste while clinker is the hydraulic binder. The major
constituents of clinker are tricalcium silicate (C3S), dicalcium silicate (C2S),
Keywords
cement mortar, superabsorbent polymer, positron annihilation
lifetime spectroscopy, positronium, porosity, hydration, curing
Related Book
Other papers in this volume
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