ASTM E2101-15(R2020) pdf free download

ASTM E2101-15(R2020) pdf free download.Standard Test Method for Measuring the Frictional Properties of Winter-Contaminated Pavement Surfaces Using an Averaging-Type Spot Measuring Decelerometer
5. Significance and Use
5.1 Knowledge of the frictional properties of a winter- contaminated pavement surface is essential to evaluate the braking effort of ground vehicles or aircraft operating on a pavement surface. The presence of contaminants on a pave- ment surface will affect the frictional properties of the surface in a manner which is difficult to evaluate by visual observation alone. The frictional properties of a winter-contaminated pave- ment surface can be characterized using a spot measuring decelerometer which provides a measurement of the surface friction and assists with the evaluation of pavement winter maintenance requirements. 5.2 The measurements produced by this test method should not be used as the sole criteria to determine pavement winter maintenance requirements. The measurements would normally be combined with visual and other observations to provide a more complete analysis of the pavement surface conditions. A certain amount of discretion is required on the part of the operator, as this test method provides only a “spot” measure- ment of the surface condition. The objective of the operator is to identify areas of the winter-contaminated pavement surface which may have lower friction and then obtain friction measurements in those areas. This makes the test method somewhat conservative by nature in comparison to the actual friction potential. 5.3 The measurements produced by this test method are dependent on the test vehicle parameters and on the braking technique of the vehicle operator.
6. Apparatus
6.1 Any Spot Measuring Decelerometer, electronic or mechanical, having the following features: 6.1.1 Capable of measuring the deceleration of a vehicle to an accuracy of within 60.02 g, including linearity and hyster- esis; 6.1.2 Capable of indicating the average deceleration rate of a vehicle during braking; 6.1.3 Capable oflow-pass filtering ofthe deceleration signal to attenuate disturbances emanating from a vehicle engine, vehicle driveline, tire vibrations, and noise or other spurious signals that may interfere with obtaining the deceleration ofthe vehicle with respect to ground; and 6.1.4 Capable of operating inside a vehicle. 6.2 Any Vehicle, having the following features: 6.2.1 Vehicle Type—An intermediate or full-size automobile ofthe sedan or station wagon body type, or a truck intended for utility or passenger/cargo use, with a vehicle mass between 1000 and 2000 kg (2200 and 4400 lb). The vehicle can be either front-wheel, rear-wheel, or four-wheel drive. 6.2.2 Brake System—Preferably, the brake system shall be capable of locking all of the vehicle wheels upon a gradual but firm application of force on the brake pedal. Alternatively, the brake system shall be capable of locking the two front vehicle wheels upon a gradual but firm application of force on the brake pedal (as in the case of a vehicle featuring a rear-wheel anti-lock brake system (ABS)). Vehicles equipped with a four-wheel ABS are not acceptable unless there is a method of disabling the four-wheel ABS when taking friction measure- ments. 6.2.3 Shock Absorbers—Shock absorbers shall be of the “heavy-duty” type. 6.2.4 Tires—All tires on the vehicle shall be of the same type construction, be of a size and type approved by the manufacturer of the vehicle for use on that vehicle, and shall show similar tread wear not exceeding 75 % of the original tread depth. Tires mounted to the same axle shall be of the same tread configuration.
7. Hazards
7.1 The hazards encountered when carrying out this test method are mainly the hazards normally associated with the operation ofa vehicle on winter-contaminated surfaces. It is the vehicle operator’s responsibility to evaluate the quality of the surface and operate the test vehicle in a suitable manner so as to prevent injury or damage to personnel and equipment. 7.2 Loss of Directional Control—A loss of vehicle direc- tional control will result when the front wheels are locked during the braking portion of the test. It is the vehicle operator’s responsibility to ensure the vehicle is headed in the correct direction prior to applying the brakes. Under most circumstances, releasing the force applied to the brake pedal will return directional control of the vehicle to the operator. If this method is used on a highway, even more caution is needed because of the narrow pavement.