TITLE:
Characterisation of Early Age Deformations in Cement Paste: Case of Chemical and Autogenous Shrinkage
AUTHORS:
Nkwenti Flavious Tanue, Tubuo Fabian, Fokwa Didier, Tchemou Gilbert
KEYWORDS:
Autogenous Shrinkage, Chemical Shrinkage, Volumetric Deformation, Water-Cement Ratio
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.8 No.4,
July
21,
2020
ABSTRACT: Concrete is commonly seen as a durable and long-lasting construction
material. However, the long-term performance of a concrete structure can be
greatly compromised by early-age cracking. This work is an experimental
contribution to study early age deformations of cement paste. Its aim is,
firstly, to develop an experimental dispositive for assessing chemical and
autogenous shrinkage, and secondly, to measure these volumetric deformations in
cement paste. The setup was done following the gravimetric method of
measurement, which exploits the Archimedes’ principle. It is made up of an
electronic balance, a data accusation unit, a temperature control unit and a
buoyancy bath. Investigations were done on Portland cement (CPA-CEM II) at the
following W/C ratios: 0.25, 0.3, 0.35, 0.4 and 0.5. It was noticed that the
water-cement ratio does not influence the magnitude of the chemical shrinkage
in a significant manner but had a kinetic effect; a lower W/C induces a faster
rate of chemical shrinkage. Autogenous shrinkage was discovered to be highly
inversely proportional to the W/C and was also noticed to be in a function of
chemical shrinkage within the first 2 to 4 hours when the paste was still
liquid.