APPLYING COVERCRETE ABSORPTION TEST TO IN-SITU TESTS ON STRUCTURES

Many permeation methods for characterizing the near-surface quality of concrete claim to have the added advantage of being applicable in sit u. This paper attempts to highlight some of the aspects associated wit h using such tests in situ, and deals specifically with experience in using the covercrete absorption test (CAT) for insitu tests on concret e structures. Some of the better known permeation test methods are lis ted, and reasons are-given for selecting the CAT for this investigatio n, in preference to other methods. Results of CAT tests performed in t he laboratory on laboratory cast samples showed the CAT can be sensiti ve to variations in water/cement ratio and curing time, moisture conte nt at the time of test, and surface orientation. Good correlations bet ween covercrete absorption and other durability index parameters were obtained for the laboratory-cast samples, but these correlations were poor or even absent when applied to in-situ tests on mature concrete s tructures. From these tests it appears that permeation methods have li ttle value for assessing the quality and state of durability of concre te structures.