ISO 10844:2014 音響学—道路車両とそのタイヤから放出されるノイズを測定するためのテストトラックの仕様 | ページ 6

3.1

sound absorption coefficient

α

fraction of the sound power incident on the test object that is absorbed within the test object for a plane wave at normal incidence

Note 1 to entry: Expressed as a percentage, it is called sound absorption.

3.2

surface profile

3.2.1

texture profile

two-dimensional sample of pavement texture generated if a sensor, such as the tip of a needle or a laser spot, continuously touches or shines on the pavement surface while it is moved along a line on the surface

Note 1 to entry: It is described by two coordinates: one along the surface plane, called “distance” (the abscissa), and the other in a direction normal to the surface plane, called “amplitude” (the ordinate).

3.2.2

irregularity

maximum distance of a surface from the measurement edge of the straightedge between two contact points of the straightedge when placed perpendicular to the surface

Note 1 to entry: Pavement characteristics at longer wavelengths than 0,5 m are considered to be above that of texture and are referred to here as irregularity.

Note 2 to entry: See Figure C.1.

3.2.2.1

longitudinal irregularity

irregularity in the longitudinal axis of the track

3.2.2.2

transversal irregularity

irregularity in the direction perpendicular to the axis of the track

3.2.3

straightedge

device used for measuring the deviation from a plane

3.2.4

megatexture

deviation of a pavement surface from a true planar surface with the characteristic dimensions along the surface of 50 mm to 500 mm, corresponding to texture wavelengths with one-third-octave bands including the range of 63 mm to 500 mm of centre wavelengths

Note 1 to entry: Peak-to-peak amplitudes normally vary in the range of 0,1 mm to 50 mm. This type of texture is the texture which has wavelengths in the same order of size as a tyre or road interface and is often created by potholes or “waviness”. It is usually an unwanted characteristic resulting from defects in the surface. Surface roughness with longer wavelengths than megatexture is referred to as irregularity.

3.2.5

macrotexture

deviation of a pavement surface from a true planar surface with the characteristic dimensions along the surface of 0,5 mm to 50 mm, corresponding to texture wavelengths with one-third-octave bands including the range of 0,63 mm to 50 mm of centre wavelengths

Note 1 to entry: Peak-to-peak amplitudes can normally vary in the range of 0,1 mm to 20 mm. This type of texture is the texture which has wavelengths of the same order of size as tyre tread elements in the tyre or road interface. Surfaces are normally designed with a sufficient macrotexture to obtain suitable water drainage in the tyre or road interface. The macrotexture is obtained by suitable proportioning of the aggregate and mortar of the mix or by surface finishing techniques.

3.2.6

microtexture

deviation of a pavement surface from a true planar surface with the characteristic dimension along the surface below 0,5 mm, corresponding to texture wavelengths with one-third-octave bands with centre wavelengths less than or equal to 0,50 mm

3.3

gradient and cross fall

3.3.1

gradient

ratio of the height difference and the length measured along the longitudinal axis of the drive lane, expressed as a percentage

3.3.2

cross fall

height difference expressed as a percentage of the length measured along the transversal axis of the drive lane

3.4

propagation area

part of the test track on each side of the drive lane

Note 1 to entry: See Figure 1.

3.5

drive lane

part of the test track where the vehicle runs

3.6

stiffness

ratio of a normal force and resulting displacement

3.7

dense asphalt concrete

asphalt in which the aggregate particles are essentially continuously graded to form an interlocking structure

Note 1 to entry: [SOURCE: EN 13108–1]

3.8

mean profile depth

average value of the height difference between the profile and a horizontal line through the highest peak (the peak level) over a 100-mm long baseline

Note 1 to entry: [SOURCE: ISO 13473-1:1997, 3.5.4]