Prof. Hanaa Ibrahim Abdel Hamid El Sayad :: Publications:

Four tests for measuring the surface properties of concrete have been studied: (1) The initial surface absorption test; (2) Figg's air permeation index (Figg) test; (3) the covercrete absorption test (CAT); and (4) the air permeability of the near surface test. Analytical models are presented for each of the tests to relate the results to fundamental properties of the concrete. Experimental results are presented for the application of a vacuum technique for preconditioning concrete in situ prior to the Figg test and CAT. The application of vacuum using the initial surface absorption test cap did not lead to satisfactory results with these tests. However, direct application of vacuum to the Figg and CAT heads prior to testing resulted in improvement of the reproducibility of the permeation indices obtained from these tests. The analytical models were then used in combination with the experimental results to draw conclusions about the choice of test method for practical applications.