Abstract:
There has been an increasing number of problems in concrete
pavements, such as cracks and delamination, in which surface hardeners have been
used, especially in car parks, industrial areas, warehouses etc. Factors that can
potentiate the occurrence of these problems are the increasing use of more
effective water reducers in concrete and also the use of binders with higher
fineness and higher tricalcium silicate content than the former ones. Concrete and
surface hardeners are both cementitious materials, which however are applied at
different instants. Distinct stages of hydration may lead to lack of homogeneity
and, eventually, to cracking and delamination. This study evaluates early hydration
and bleeding behaviour of concrete, which are relevant factors for finishing with
surface hardeners. The influence of chemical admixtures and environmental
conditions were tested by penetration resistance and bleed water, which highlights
the shortening of the period in which surface hardener application is possible.
