A laboratory study evaluating strength and permeability characteristics of a porous concrete mix is presented. The experiments included compressive strength tests and falling head permeability tests on clean specimens. Falling head permeability tests were repeated after introducing some sand-salt mixture on the top surface of the specimens as a simulation of winter surface applications. The experiments were performed on specimens of three sizes: 7.62 cm (3”), 10.16 cm (4”), and 15.24 cm (6”) in diameter to examine if the test results were influenced by the size of the specimens. Multiple specimens were tested for a particular size. For the particular mix examined, the compressive strength ranged between about 4.5 MPa (650 psi) and 7.6 MPa (1,100 psi) with an average of about 6.2 MPa (900 psi). Permeability test results yielded hydraulic conductivity ranging between 0.68 cm/s and 0.98 cm/s (971 in/hr and 1,387 in/hr) with an average of about 0.87 cm/s (1,233 in/hr). All of the above values were within the expected range found in the literature. The reduction in the hydraulic conductivity was about 15% with the surface application of the sand-salt mixture. The observed variations in the properties were also similar to those reported in the literature. Therefore, any effects arising from the size of the specimen on the test results could not be distinguished from those arising from normal variations among specimens.
Abstract