The Micro-Deval test measures abrasion resistance and durability of mineral aggregates. An aggregate sample is placed in a sealed stainless steel jar with an abrasive charge of up to 5,000g of 9.5mm diameter stainless steel balls and water, then rotated at 100rpm for two hours. Aggregate quality is determined by percentage loss in gradation results at completion. Smaller equipment size, lower sample quantities and a simpler procedure make the method easier and less costly to perform than traditional methods. The H-3875 Micro-Deval meets current ASTM, AASHTO, and Canadian test methods, as well as more stringent Texas DOTrequirements.
The micro-deval test measures abrasion resistance and durability of mineral aggregates. An aggregate sample is placed in a sealed stainless steel jar with an abrasive charge of up to 5,000g of 9.5mm diameter stainless steel balls and water, then rotated at 100rpm for two hours. Aggregate quality is determined by percentage loss in gradation results at completion. The micro-devals smaller size, smaller sample quantities and simpler procedure make this test method easier and less costly to perform than traditionalmethods.
The micro-deval meets current ASTM, AASHTO, and Canadian test methods, as well as more stringent Texas DOT requirements. This contemporary version of the micro-deval test should not be confused with older versions originating in Europe which use different equipment and test protocol. A sophisticated electronic controller with optical sensing system accurately tracks test time, total revolutions and rpm of jars. Test duration may be controlled by either elapsed time or total revolutions. Jars stop within a fraction of one revolution at test termination. Jar revolution and speed data may also be used as a verification of machineperformance.
Sample jars revolve behind polycarbonate doors equipped with safety interlocks, so no moving parts are exposed during operation as opposed to older designs, which used unguarded open rollers. The micro-deval machine is a two-tier unit with sturdy steel frame. Each tier carries one stainless steel 5 liter sample jar, which has a 194mm ID and a 170mm internal height with locking cover. Power to the rubber-covered rollers is supplied by a 3/4hp, electric motor through a gear transmission and chain drive. The unit is supplied with two jars and two 5,500g abrasive charges. A magnet is included to assist in removing the abrasive charge after the test is complete. For additional sample preparation capacity and greatly reduced testing times, it is recommended that additional sample jars and abrasive charges beused.
Overall dimensions are: 20.5" x 13.5" x 38" (521 x 343 x965mm).
