Severity levels Possible causes Description

22 the dimensions of concrete slab on the bottom, it helps to know this defect ASTM D6433, 1999 David, 2006. Figure 2.7 Reflection Cracking GTC, 1998

b. Severity levels

Low level of intensity L: There can be such a level in the following cases: - Is full of cracks introduced less than 10 mm. - Isolated cracks with insulation in good condition can be determined display. Medium level of intensity M: There is one of the following cases: - Non-filled cracks with a width of between 10 - 70 mm. 23 - Cracks filled with non-display greater than 75 mm surrounded by a badly broken secondary. - Cracks filled with any offer and is surrounded by secondary badly broken Higher level of intensity H: There is in any of the following cases - Cracks filled or not filled surrounded by strongly medium or high of secondary cracks. - Cracks filled with non-display greater than 75 mm. - Cracks introduced about 100 mm and surrounded by volatile badly broken or broken.

c. How to Measure

Measured cracks reflective linear meter intervals, and must record length and level of intensity for each slot. In some cases several different levels of intensity in one sector, in this case must be recorded along the cracks and the level of intensity and intensity of each separately. Measured by the area affected by the defect length of the affected area multiplied by one meter, and the defect density is calculated by dividing the area affected by the total area of the section scanned.

d. Possible causes

Movement is the concrete slab of concrete resulting from the heat and humidity, which in turn reflected on the surface of asphalt pavement is the main cause of reflective cracking joints.

2.3.1.6 Slippage Cracks Sliding Cracks:

a. Description

Slippage cracks are crescent- or half-moon shaped cracks having two ends pointed away from the direction of traffic. see figure 2.8They are produced when braking or turning wheels cause the pavement surface to slide and deform. This usually