7.13 : コンクリートの耐摩耗性

Concrete abrasion can occur from vehicular wear on surfaces or abrasive solids in water, which erodes canal linings.

The shot-blast test evaluates concrete erosion from waterborne solids by blasting 2000 steel shots, each equal to ASTM No. 20 size, from a 0.25-inch nozzle at 90 psi, 4 inches from the concrete sample.

In the revolving disc test, three flat plates rotate in a circular motion at a frequency of 0.2 cycles per second, with each plate also turning on its axis at 4.7 cycles per second. Silicon carbide serves as the abrasive substance between plates and concrete.

The steel ball abrasion test exerts a force on a head that rotates, separated from the concrete by steel balls; the test involves using circulating water to clear away material worn down.

The dressing wheel test involves a modified drill press that applies force to three sets of seven rotating wheels in contact with the sample, with the driving head spinning at a frequency of 0.93 cycles per second for 30 minutes.

The amount of concrete surface abrasion is quantified by the depth of wear observed in these tests.