Stow manual Stopping the RCC130H Series Gasoline Powered Crack Saws, Basic definitions

ASSEMBLY INSTRUCTIONS/OPERATIONS

STOPPING THE RCC130H SERIES GASOLINE POWERED CRACK SAWS.

1)Position the quick change height lever over center to its rear most (up) position.

2)Stop the Crack Saw by moving the engine throttle control lever to the idle speed position. Turn the ignition switch located on the engine to the OFF position. Consult the material supplied by the engine manufacturer for specific information.

OPERATIONAL PARAMETERS AND TECHNIQUES FOR THE RCC130H SERIES CRACK SAW.

Basic definitions.

There are very few aspects of the pavement maintenance industry that all members, including contractors, engineers, researchers and government agencies can agree on except the inevitability of cracks forming in all types of pavements. To properly address the crack repair procedures, contractors must have a basic understanding of why crack repair is beneficial, crack types to address and the repair materials and methods available.

A basic understanding of the difference between crack filling and crack sealing and the working knowledge to understand which one is appropriate for a specific job application is essential for any pavement maintenance contractor.

An industry accepted definition of crack filling is the placement of materials into cracks to reduce water intrusion and reinforce the adjacent pavement. Crack sealing is the placement of specialized materials either above or into working cracks to prevent the intrusion of water and incompressibles such as sand, aggregate and dirt.

Why Do It at All?

Crack sealing is used as a first line of defense against the deterioration of pavement because of its inherent benefits:

a)It protects the base and sub-base. A good pavement requires a base and sub-base of high structural integrity. Effective crack sealing procedures eliminate water from entering and weakening these areas. The resulting weakness can result in the loss of structural support, which can then further result in the formation of additional cracks and settling around the crack area.

b)It preserves the pavement adjacent to the cracking. Cracks that are properly cleaned and sealed contain filler materials that firmly adhere to the crack sides during times of both expansion and contraction. Without the addition of these filler materials, the adjacent pavement would have increased exposure to the elements, resulting in increased oxidation of the binder, hardening and secondary cracking along the main crack.

c)It eliminates the damaging effects of incompressibles such as sand, aggregate and dirt. When these materials get into a crack they can restrict crack closure during periods of warm weather. The resulting compressive stresses at the faces can create spalling and loosening. In some highly oxidized pavements these stresses can even create pavement lipping, which is the upheaval of pavements at their transverse cracks.

d)It extends pavement life. Sealing procedures allow the contractor to effectively exert control over the base and sub-base conditions, pavement interference and crack growth, thereby extending the pavement's service life.

Types of Cracks.

There are several basic types of cracks:

a)Reflective. This type of crack appears primarily in resurfacing projects, although it can also occur in a new pavement surface. Reflective cracks occur when an existing crack or joint in the underlying pavement structure reflects upward through the surface.

b)Joint. A joint is the edge of the individual paving pass made during construction. Such construction joints usually have a lower density than the remaining material. When the placed mats do not bond properly (for any number of reasons), joint cracks can appear.

c)Slippage. Slippage cracks are usually crescent shaped and are created by heavy traffic that is either stopping, turning or climbing a hill. Resultant stresses can cause a bond failure between upper and lower pavement layers. The open end of the U shaped crack always points in the direction of the applied force.

d)Thermal. All pavements expand and contract due to temperature variations. This movement can create cracks. To better allow for movement, pavements need to be constructed with the correct percentage of air voids, which provide for internal stress relief. When the air void percentage is not correct, thermal cracks appear.

RCC130H-CRACK SAW OPERATION AND PARTS MANUAL REV #1 (11/18/04) PAGE 29