Abstract: One or more infrared heat lamps provide radiant heat at the top of a laboratory oven structure having a permanently open front and ventilation openings rearwardly thereof, so air will be drawn across a mass of discrete matter constituting a test sample being exposed to radiant heat within the oven. The interior of the oven structure is lined with a heat-resistant material, such as sheet asbestos, and a height-adjustable shelf arrangement within the oven provides for placing the test sample to be dried either closer or farther away from the infrared lamp or lamps. The oven is especially useful for drying samples of asphaltic road-building materials for highway construction or maintenance.