The permeability of concrete is one of the most important factors influencing the durability of a concrete structure, and is a property of great interest to designers of concrete structures. However, very little data on this property of concrete exist, and there is not any widely used standard procedure for determining the permeability of concrete. The major problems generally encountered in performing a water-permeability test on concrete include (a) the great amount of time required for each test; (b) the possible leakage of water through the sides of the test specimens; and (c) the extremely low water flow rate, which makes an accurate measurement difficult to obtain. This paper presents a test set-up and procedure that have been developed through experimentation and that have proven effective in dealing with the above-listed problems. The developed test set-up can test 20 concrete specimens simultaneously by using 20 permeability apparatuses, which are connected to the same regulated compressed air source. The concrete specimens can be placed into and removed from the permeability apparatuses with a minimal loss of time and with no disturbance to the other test specimens. The problem of the effects of water evaporation on the measured flow rate has also been effectively dealt with. Another major advantage of this test set-up is that it can be duplicated easily and economically. This paper also presents the results of permeability tests on three different Florida concretes subjected to four different curing conditions. The test set-up has been demonstrated to be both reliable and efficient for determining permeability on a large number of concrete specimens.
Samenvatting