Scope:- Specifies the method for determining the
initial surface absorption of oven-dried specimens
and of concrete that cannot be oven dried.
Test for determining the initial
surface absorption of concrete
initial surface absorption
The rate of flow of water into concrete per unit area
after a stated interval from the start of the test and
at a constant applied head and temperature
after a stated interval from the start of the test and
at a constant applied head and temperature
Capillary scale :-
From the dimensions of the
cap, the area of contact of the water with the
specimen shall be calculated and recorded in square
millimetres,
cap, the area of contact of the water with the
specimen shall be calculated and recorded in square
millimetres,
A1
. The area of the bore of the capillary
in square millimetres,
. The area of the bore of the capillary
in square millimetres,
A2
, shall be calculated from
the equation
, shall be calculated from
the equation
A2
= pr
2
, using the value of r
from.
= pr
2
, using the value of r
from.
A scale shall now be prepared to mount behind the
capillary tube and shall be marked off in units
of 0·01, spaced apart.
capillary tube and shall be marked off in units
of 0·01, spaced apart.
NOTE The scale and capillary are now prepared so that the
movement of the water along the capillary over a one-minute
period is the initial surface absorption in millilitres per square
metre per second at the time of the test.
movement of the water along the capillary over a one-minute
period is the initial surface absorption in millilitres per square
metre per second at the time of the test.