Methods for Increasing the Harshness of Texture on Old Concrete Pavements: Mechanical Alteration with the Klarcrete Machine

About the report:

Experiments were performed with the British Klarcrete machine-on the Emporia bypass (I-95) in Greensville County to determine if it was capable of removing the top layer of roadway to a depth of between 1/8 to 1/4 inch, and in so doing expose a fresh surface of highly fractured coarse aggregate to give a better skid resistance. In addition, experimentation was performed to determine if the machine could be used as an efficient means of completely cleaning bridge decks of coal tar epoxy prior to resealing. The machine employs 11 percussive hammers mounted side by side and each separated by 2 1/4 inches that strike the pavement approximately 1,500 times per minute and cut a four-foot swath. Each impact removes only a small amount of pavement and in so doing does not injure the surrounding pavement. The sole power requirement is a 600 cubic foot per minute compressor producing 100 pounds per square inch. The machine is self-propelled, and its forward speed determines the depth of surface that is removed. The maximum width of surface removal per pass of the machine is approximately 4 feet. In the experiments the machine removed the surface layer of pavement and exposed a new surface of coarse aggregate with fractured jagged edges slightly raised above the surrounding mortar with no irregularities for water to pond and in so doing did not impair the riding quality of the road. Extensive skid testing proved that the skid resistance was raised significantly under specified conditions. The bridge cleaning experiment was successful with the bridge being cleaned more efficiently, faster, and with less expense than by sandblasting.

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