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This Regulation was approved by the Ministry of Communications of the People's Republic of China on April 3, 2007, and implemented from August 1, 2007.
The Transportation Industry Measurement Technical Committee is responsible for the explanation of this Regulation.
Contents
1 Scope 1
2 Normative References 1
3 General 1
4 Measuring performance requirement 2
5 General Technical Requirements 2
6 Control over Measuring Instruments 2
Annex A Format of Verification Record 7
Annex B Back Format of Verification Certificate 8
Annex C Content of Verification Certificate 9
Annex D Setting Block 10
Vehicle Bearing Road Laser Video Distress Detecting System
1 Scope
This Regulation is applicable to the first verification, subsequent verification and in-use inspection of vehicle bearing pavement laser video distress detecting system (hereinafter referred to as "distress detecting system").
2 Normative References
JTJ 059 Field Test Methods of Subgrade and Pavement for Highway Engineering
JT/T 678-2007 Vehicle Bearing Road Laser Video Distress Detecting System
For purpose of this Regulation, the current and effective editions of the documents above shall apply.
3 General
Laser video distress detecting system is a device to detect and analyze road pavement deformation and crack through high speed digital camera technique and light source like three-dimensional imaging laser bean, strong light and sun light, and it consists of three-dimensional imaging laser source, strong light source or sun light source, high speed digital high-resolution imaging device, longitudinal distance sensor, road distress computer digital image processing system (as shown in Figure 1).
Figure 1 Diagram of laser video distress detecting system
a) Road deformation detecting system; b) Road crack detecting system
4 Measuring Performance Requirement
4.1 Road crack width discrimination: where road crack width is not less than 2mm, the discrimination rate is 100% and the indication error of crack width value identification shall not be greater than 1mm.
4.2 Indication error of road distress area shall not be greater than 10%.
4.3 Error of longitudinal distance sensor shall not be greater than 0.1%.
4.4 Repeatability test: road distress statistics output disturbance system CV shall not be greater than 5%.
5 General Technical Requirements
5.1 Appearance of all parts of laser video distress detecting system shall be bright and clean, and free of damage and rust; surface paint layer shall be smooth and uniform.
5.2 Nameplate and mark of laser video distress detecting system shall be distinct. The content on label plate shall include product model, product name, manufacturer's name, product technical parameters, production number and manufacturing date; the content on mark shall include use number and latest verification date.
6 Control over Measuring Instruments
6.1 Verification conditions
6.1.1 Environment conditions for verification
The environmental conditions for verification are as follows:
a) Ambient temperature: 0℃ ~ 50℃;
b) Ambient humidity: ≤85%;
c) Requirements of test road section: straight road section free of water accumulation, snow/ice, pollution, and intersection;
d) Running speed of bearing vehicle: ≥100km/h.
6.1.2 Verification tools
6.1.2.1 Steel tape: 0m ~ 50m, with division value 1mm.
6.1.2.2 Temperature & relative humidity indicator: temperature span -30℃ ~ +60℃, with division value 0.2℃;
Humidity range 0 ~ 100%, with division value 1%.
6.1.2.3 Setting block for road crack width video detecting (hereinafter referred to as "setting block"): aluminum alloy made, with the dimensions as specified in Annex D hereto.
6.1.2.4 Road distress area testing panel
Material: made of aluminum alloy, ABS plastic or other suitable material; dimensional requirement: testing panels with a thickness of not less than 5mm and an area of 100cm2 ~ 1600cm2 (square, rectangle, regular triangle, rhomboid and round, 2 pieces respectively).
6.1.2.5 Vernier calipers: 0mm ~ 150mm; with scale division: 0.02mm.
6.2 Verification items
Verification items of laser video distress detecting system are as shown in Table 1 and verification record format is detailed in Annex A.
1 Scope
2 Normative References
3 General
4 Measuring performance requirement
5 General Technical Requirements
6 Control over Measuring Instruments
Annex A Format of Verification Record
Annex B Back Format of Verification Certificate
Annex C Content of Verification Certificate
Annex D Setting Block
