Before knowing the term workability let us look at some of the definitions given by scientists and researchers.
Definitions of Workability of Concrete
According to Granville “it is that property of the concrete which determines the amount of useful internal work necessary to produce full compaction.”
Powers defined it as “that property of plastic concrete mixture which determines the ease with which it can be placed and the degree to which it resists segregation”
ACI (American Concrete Institute) defines it as ‘that property of freshly mixed concrete or mortar which determines the ease and homogeneity with which it can be mixed, placed, consolidated and finished’.
ASTM (American Society for Testing and Materials) defines it as “that property determining the effort required to manipulate a freshly mixed quantity of concrete with minimum loss of homogeneity”.
Importance and Significance of Workability
From these above definition it is very clear that there exist no straightforward definition for the term “Workability”. In very simple words we can say that workability of concrete means the ability to work with concrete. A concrete is said to be workable if
It can be handled without segregation
It can be placed without loss of homogeneity
It can be compacted with specified effort
It can be finished easily
In every construction work we use different quantitative or qualitative terms to express workability. Before specifying workability for any work a concrete technologist must keep the following things in mind.
Type of construction work
Method of mixing
Thickness of section
Extent of reinforcement
Mode of compaction
Distance of transporting
Method of placing
Concrete that can be placed readily without segregation or separation in a mass dam could be entirely unworkable in a thin structural member.
Workable concrete compacted by means of high frequency vibrators would be unworkable if vibrators could not be used and hand tamping and spading were required.
Concrete having suitable workability for a pavement might be unsuitable for use in a heavily reinforced section.